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The Oort cloud: Astronomy’s Most Captivating Supposition

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The Oort cloud: Astronomy’s Most Captivating Supposition

By: Elisabeth Bauman, Dawn Deguire, Taralyn Donohue, Gurleen Lehal, Jacey Nyberg, Brianna Stene, and Phillip Zinck

 

Humans have always been fascinated with outer space. One fascination has been the topic of the Oort cloud. The Oort cloud is theorized to be a large region of icy debris, thought to be thousands of astronomical units (AU) across, that surrounds our solar system.1 While numerous objects in our solar system have been known for many millennia, the theories of the Oort cloud and discoveries of Dwarf Planets are relatively recent and still shrouded in mystery. The Oort cloud has been one of the most interesting theories in astronomical science. Since the first discovery by a Dutch astronomer by the name of Dr. Jan Oort in the 1950s, the properties of the Oort cloud have been a topic of intriguing discussion.2 This makes it particularly interesting to answer the questions of what exactly is the Oort cloud, what lies within it, and how can we verify its existence?

The answer(s) to this question is particularly important in modern astronomy because it involves actual evidence of discoveries such as dwarf planets and comets. So far, the most accepted way to support the theory of the Oort cloud is by using advanced and modern technology to first find objects within the Oort cloud, rather than defining the cloud itself. Furthermore, concrete evidence of the Oort cloud can help astronomers in determining the origin of planet formation from protoplanetary disk processes as they have been theorized to be connected.1 Therefore, the Oort cloud is a theoretical body of matter that is believed to hold within it a historical record of the origins of our solar system. While the Oort cloud is still largely hypothetical, the science and origin of dwarf planets and long-range comets supports the theory of the Oort cloud.

 

 

Overview of Research 

  • The Oort cloud
    • What is it?
    • How was it formed?
  • The First Theorist: Jan Oort
  • The evidence that may suggest the theory of the Oort Cloud 
    • Long-period comets
    • planet formation and protoplanetary disks
    • Dwarf planets
  • Recent Developments
  • Conclusion

 

 

The Oort Cloud 

What is it?

 

 

Figure 1: Diagram of the Oort cloud. https://space-facts.com/oort-cloud/

The Oort cloud is theorized to be a collection of icy objects, also known as planetesimals, that are within a region far beyond our planetary solar system. The icy objects of the Oort cloud surrounding our solar system lie beyond the Kuiper belt.3 Thus, the Oort cloud is theorized to “extend outward almost halfway to the nearest stars.”4 That is around 50,000 AU from the Sun. 

 The Oort cloud  is theorized to have up to 10 trillion (1012) objects residing in it, and has been referred to as “the frontier of the solar system.”5, 6 Additionally, it fits with observations of comets in our solar system.1 Astronomers believe many long-period comets, objects that originate from distances greater than 50,000 AU from the sun,  and dwarf planets, also known as trans-neptunian objects, could also originate in the Oort cloud. However, to date, there has not been enough correlation between a proposed theory and observational data to prove the existence of the Oort cloud.1

 

 

How was it formed?

Figure 2: The Oort cloud relative to the Kuiper Belt. https://solarsystem.nasa.gov/resources/491/oort-cloud/?category=solar-system_oort-cloud

Currently, there is a single most promising idea for the formation of the Oort cloud. It states that after the planets formed 4.6 billion years ago, there were many planetesimals left over, near these newly formed planets. A planetesimal is the leftover chunks, composed of the same material the planets were made of. These chunks then became scattered throughout the solar system; some left the solar system completely, due to the gravity of the larger planets, such as Jupiter. The chunks that remained in the solar system were held in an eccentric orbit around the sun. A combination of the sun’s gravitational pull and the galaxy caused these chunks to collect on the edge of our solar system, where other planets could no longer perturb them, thus explaining the formation of the Oort cloud.7

Another theory suggests that, early in the life of our solar system, a large planet was thrown from its orbit around the Sun. In its journey to the edges of our solar system, it brought objects from the Kuiper Belt into orbit around itself into the inner Oort cloud.4 It is not known if this large planet is still present deep within the Oort cloud (though this would support the theories of Dr. Scott Sheppard from the Carnegie Institution for Science in Washington, D. C. who says a large planet in the Oort cloud would explain the orbitals of dwarf planets), or if this hypothetical planet has left our solar system altogether.

 

 

The First Theorist: Jan Oort

Figure 3: Dr. Jan Oort. https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4806

Dr. Jan Hendrik Oort was a Dutch astronomer born in Franeker, Netherlands, on April 29, 1900, and lived till the age of 92. When Dr. Oort was 17, he was admitted to the University of Groningen to study physics. After Oort’s time at the University of Groningen, Dr. Oort accepted a position at the Leiden University Observatory, where he was eventually offered a position as a Professor. However, he ended up leaving his teaching position during the German occupation of the Netherlands in 1942. After the war in 1945, he returned to the university, where he became the director of the observatory until 1970.7 During this time, Dr. Oort observed the night sky and was particularly interested in comets. In 1950 he developed a theory about the origins of comets from the Oort cloud. Some of Oort’s other notable works include Galactic Halo discovery, calculating the distance between the earth and the center of the milky way, the first evidence of Dark Matter, and the polarization of light from the Crab Nebula.8 Because of these great discoveries, Dr. Jan Oort is considered to be one of the most important and influential astronomers of the 20th century.

Dr. Jan Oort studied comets and wondered about their origins; he theorized that the solar system was surrounded by a vast, spherical cloud consisting of comets and other stellar debris. However, this cloud was not visible due to the immense distances involved, and its location at the edge of the solar system. The cloud was thought to have a radius up to 100,000 AU or 1.5 light-years.9 This spherical cloud of icy objects including comets that revolve around the sun at extremely long distances is known as the Oort cloud. The Oort cloud is an astronomical region in space that is often referred to as a shell surrounding our solar system.1 Dr. Oort hypothesized that new comets are objects orbiting the sun near the edge of its gravitational zone whose orbits have been disturbed by nearby stars. Eventually, these comets travel close enough to the sun that they can be viewed. An example of this occurrence is Halley’s Comet, which almost certainly originated from the Oort cloud, but now resides as a member of the Kuiper Belt. Dr. Jan Oort’s theories about the Oort cloud have been widely accepted by the scientific community. Without his theory, scientists may not have had any idea of where comets and other celestial objects come from, as it is impossible to observe the Oort cloud physically.

 

 

Evidence that may suggest the theory of the Oort cloud

By definition, the Oort cloud is a theoretical, spherical cloud of predominantly icy planetesimals that is believed to surround the sun at a distance of up to around 100,000 AU (2 ly). This places it in interstellar space, beyond the Sun's Heliosphere where it defines the cosmological boundary between the solar system and the region of the sun's gravitational dominance.10  Since the definition of phenomenon is an observable fact or event, the Oort cloud is not an astronomical phenomenon as it has never been observed. Astronomers can only study what they believe are the results of the Oort cloud, or objects that originate within the Oort cloud. 

These discoveries include evidence of long-period comets, the existence of dwarf planets, and theories of planet formation from protoplanetary disks of the Oort cloud. However, exploring the Oort cloud presents numerous difficulties, most of which arise from the fact that it is incredibly distant from Earth. By the time a robotic probe could actually reach it and begin exploring the area in earnest, centuries will have passed here on Earth. Not only would those who had sent the probe out in the first place be long dead, but humanity will have most likely invented far more sophisticated probes or even manned craft in the meantime.10

 

Long-period comets

Figure 4: Example of a long period comet. http://astronomy.swin.edu.au/cosmos/L/Long-period+Comets

Kuiper belt objects (KPOs) are similar to comets and are rich in water ice. Unlike the Oort cloud, whose objects are at too great a distance to be observed, thousands of KPOs have been observed in the last 25 years. Therefore, the study of long-period comets is crucial to understanding what the Oort cloud contains.

For example, a 2019 study of all known long-period comets (647) has provided evidence that the gravitational pull of stars can influence a comet’s motion when coming within 1000 AU from it. This phenomenon, known as a stellar perturbation, is found to be a rare phenomenon. In addition to closeness in proximity, other specific conditions must be met including the star having a small velocity (the speed at which an object moves).11

The study only found two instances where perturbations had occurred, concluding that it is rare for a star approaching our solar system to meet all the conditions necessary to significantly perturb the observable long-period comets. Unfortunately, due to having access to inconsistent data on the motion of stars and comets, testing the reliability of the research approach is not possible. However, the study is the first ever confirmation of the Oort cloud hypothesis that uses real stars rather than a simulation.

 

Figure 5: Protoplanetary disk enclosing the star, HD 163296. https://astrobiology.nasa.gov/news/planets-still-forming-detected-in-a-protoplanetary-disk/

Planet formation and protoplanetary disks

The connection between Exo-Oort clouds and planet formation has been a theory suggested by many. It is well known and supported by the findings of the Hubble Space Telescope that planets formed from the same collision of the nebula that formed the Sun. When this nebula collided it turned into a protoplanetary disk containing dust, ice and gas. These particles then formed to create planetesimals, which further led to the formation of planets.12 

Figure 6: Possible planet formation from a protoplanetary disk. https://astrobites.org/2018/08/23/filling-dust-gaps-in-our-knowledge-of-planet-formation/

The Oort cloud is largely made up of similar planetesimals that created our universe. Thus, the suggestion that planets can be formed within the protoplanetary disks within the Oort cloud could be a topic greatly supported. However, this still requires significant evidence of planet formation within the range of the Oort cloud. Such evidence can include the possible existence of dwarf planets like Sedna.

 

Dwarf Planets 

While the Oort cloud has remained largely hypothetical due to the challenge of actually observing objects within its borders, within the past twenty years the discovery of dwarf planets beyond the Kuiper Belt have reinforced the belief of its existence. The definition of a dwarf planet differentiates it from a planet on two criteria: unlike the dwarf planet, a planet has cleared the neighborhood around its orbit, and the definition of a planet does not include the satellite distinction.13

Figure 7: Sedna, the dwarf planet. https://phys.org/news/2015-09-dwarf-planet-or10.html

In 2004 the first object beyond the Kuiper Belt was identified as a small, planet-like object. The object was believed to be a small dwarf planet, named Sedna.4  Sedna’s orbit brings it 76 AU away from our Sun.4 In order to qualify as a dwarf planet, a body must have enough mass to assume a rounded shape and may not be a satellite of another body. While the plotted orbit of Sedna indicates it is not a moon, the planet's shape is unclear. Nonetheless, numerical simulations modelling the formation of an Oort cloud suggest that Sedna’s orbit may belong within the Oort cloud’s parameters.14 Sedna is extremely far from the sun, almost twice as far as Pluto. Due to its remoteness, it is believed that Sedna was not an object of much geological activity and has very few craters. As a result, Sedna’s surface

Figure 8: The Orbit of Sedna. Image from book: T. Dickinson, The Universe and Beyond, 4th ed. (Firefly Books, New York, 2004), p. 70.

may be smooth and uniform—possibly untouched since its formation. Sedna takes 10,500 years to orbit around the Sun, and its elliptical orbit is currently bringing it closer towards the Sun. In 2075, it will begin its journey away once again. This orbit corresponds to the predicted orbit of objects within the Oort cloud, providing exciting evidence for the Oort cloud.4 Additionally, Sedna remains an important discovery in astronomy because Sedna and objects like it are believed to be “pristine samples of the solar systems earliest days,” thus, bringing us closer to understanding the nature of the Oort cloud.15

 

 

Ten years after the discovery of Sedna, another dwarf planet was discovered in 2014. This discovery was the result of the work of two scientists, Dr. Scott Sheppard from the Carnegie Institution for Science in Washington, D. C., and his partner, Dr. Chadwick Trujillo from the Gemini Observatory in Mauna Kea, Hawaii. They used the Dark Energy Camera, which has one of the largest fields of view of any telescope, to identify this dim object, as well as the Magellan Telescope (6.5 meter) at Carnegie’s Las Campanas Observatory in Chile to observe and calculate further information (like its orbital). The dwarf planet remains nameless, but is referred to as 2012VP113.16 Despite how far away this planet is from

Figure 9: Pictures taken by Dr. Sheppard on November 5, 2012, depicting the 2012 VP113. Credit: Scott S. Sheppard / Carnegie Institution for Science. https://astronomy.com/news/2014/03/major-new-dwarf-planet-discovered

our solar system, it is still regarded as being located in the “inner” part of the Oort cloud. The Kuiper Belt is 30-50 AU away from the Sun, and 2012VP113 is far further out than the objects in the Kuiper Belt. In fact, when 2012VP113’s orbit brings it nearest the Sun, it is still 80 AU away, and its orbit takes it hundreds of AU away from the Sun. 2012VP113 is the farthest known object in our solar system, though Dr. Sheppard and Dr. Chadwick Trujillo hypothesize that there may be a much bigger planet in the Oort cloud that influences the orbit of 2012VP113.16

 

 

Dwarf planets are believed to hold samples of the earliest days of the solar system, yet, only recently have been recognized as a new class of astronomical objects in 2006. Dwarf planets often exhibit peculiarities that make them apparent outliers in their neighborhood within the solar system. Efforts to place in context new discoveries of dwarf planets such as Sedna and 2012VP113 are probing scientists to think farther involving the solar system, quite literally. As Dr. Sheppard eloquently put “the search for these distant inner Oort Cloud objects beyond Sedna and 2012 VP113 should continue, as they could tell us a lot about how our solar system formed and evolved.”16 Studying these objects and understanding their unique properties have led to leaps in understanding our solar system and its history. As new theories develop, and existing theories evolve, the present information is essential to realizing the actuality of the Oort cloud.

 

 

Recent Developments

As of today, no missions have been sent to explore the Oort Cloud, but five spacecrafts will eventually get there, according to NASA.3 These spacecrafts include Voyager 1 and 2, New Horizons, and Pioneer 10 and 11. A major obstacle, as discussed in this paper, is that the Oort Cloud is so distant. Consequently, the power source for all five spacecrafts will be dead centuries before they reach the inner edge of the Oort Cloud. To put things into perspective, Voyager 1 is the fastest and farthest of the interplanetary space probes currently leaving the solar system. Even though Voyager 1 travels at approximately a million miles per day, it will take the spacecraft about 300 years to reach the inner boundary of the Oort Cloud and an estimated 30,000 years to exit the far side.3 This lengthy expedition is something Astronomers are currently devising. 

Figure 10: Voyager 1 Courtesy NASA/JPL-Caltech https://voyager.jpl.nasa.gov/galleries/images-of-voyager/

The exploration and study of the Oort Cloud and the materials that have originated from the Oort Cloud continues to be pursued by the astronomical community around the world. For instance, the European Space Agency has proposed a Comet Interceptor mission for launch in 2028 which aims to become the first spacecraft to get a close-up of a “dynamically new” comet or interstellar object that has not passed near the sun before.17 So far, spacecrafts have only visited comets that have made repeated passages close to the sun, where solar radiation breaks down ice and other material that are evidence from the birth of the solar system. The type of comets sought by this mission have originated in the Oort Cloud. Professor Colin Snodgrass, an astronomer at the University of Edinburgh and deputy lead of the Comet Interceptor science team, believes that the Large Synoptic Survey Telescope (LSST), currently under construction in Chile, will be critical in finding a comet destination.17 The new telescope is set to be operative by the end of 2022, and will be able to detect smaller asteroids and comets farther from the sun than ever before. With this development, “scientists expect to find comets with up to five or six years of warning before they reach perihelion, the closest point to the sun in their trajectories."3 This forewarning will allow enough time to study the object, plot the trajectory, and reach it.

 

 

Conclusion 

Further discoveries and concrete evidence to prove the existence of the Oort cloud would be revolutionary for the world of astronomical science. The theoretical nature that surrounds this mysterious region of our solar system, first identified by Dr. Jan Oort and defined as a collection of icy objects known as planetesimals, makes it a particularly attractive area of study.3 Using modern technology to identify objects that lie within the Oort cloud and gathering concrete evidence is the most promising method used by astronomers to finally prove the existence of the Oort cloud. The identification of long-period comets, protoplanetary discs, and dwarf planets are the main discoveries that the world of astronomy could use to prove this theory. The Oort cloud is a historical record of the beginning of our solar system and is a representation of how vast and wide our solar system is. The theoretical existence of the Oort cloud has the potential to unlock the mysteries not only of our own solar system but of the entire Galaxy.2 

 

 

References

1Phys Org. Oort clouds around other stars should be visible in the cosmic microwave background. https://phys.org/news/2018-08-oort-clouds-stars-visible-cosmic.html (Accessed March 20, 2020).
2P.R. Weissman, Nature 344, 825 (1990).
3NASA. Oort Cloud. https://solarsystem.nasa.gov/solar-system/oort-cloud/overview/ (Accessed March 5, 2020).
4T. Dickinson, The Universe and Beyond, 4th ed. (Firefly Books, New York, 2004).
5A. Fraknoi, D. Morrison, and S.C. Wolf, Astronomy. Chap 13., Sec 4
6L.A. McFadden, P.R. Weissman, and T. V. Johnson, Encycl. Sol. Syst. 1707338 (2007).
7NASA. Oort Cloud. https://solarsystem.nasa.gov/solar-system/oort-cloud/in-depth/ (Accessed March 21, 2020).
8TIMELINE INDEX. Jan Oort, explorer Milky Way and Dark Matter. https://www.timelineindex.com/content/view/3901 (Accessed March 29, 2020). 
9The Editors of Encyclopaedia Britannica. Jan Oort. https://www.britannica.com/biography/Jan-Oort (Accessed March 21, 2020).
10M.Williams, Universe Today. What is the Oort Cloud? https://phys.org/news/2015-08-oort-cloud.html (Accessed March 21, 2020).
11Rita Wysoczańska, Piotr A Dybczyński, Małgorzata Królikowska, First stars that could significantly perturb comet motion are finally found, Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 2, January 2020, Pages 2119–2128, https://doi-org.cyber.usask.ca/10.1093/mnras/stz3127 (accessed March 20, 2020).
12T. èrése Encrenaz, Eur. Rev. 10, 171 (2002).
13THE PLANETS. Dwarf Planets: Interesting Facts about the Five Dwarf Planets.  https://theplanets.org/dwarf-planets/ (Accessed March 21, 2020). 
14N.A. Kaib, R. Roskar, and T. Quinn, Icarus. 215, 491 (2011).
15NEW TELESCOPIC WATCH. Top 6 Facts About Sedna, the Dwarf Planet. https://telescopicwatch.com/sedna-facts/  (Accessed March 29, 2020). 
16Carnegie Institution for Science. Major new dwarf planet discovered. https://astronomy.com/news/2014/03/major-new-dwarf-planet-discovered (Accessed March 1, 2020).
17SPACEFLIGHT NOW. European space mission to get close-up view of new comet. https://spaceflightnow.com/2019/06/21/european-space-mission-to-get-close-up-view-of-new-comet/ (Accessed March 29, 2020). 

 

The Technology Behind the Discovery of Saturn’s 20 New Moons

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 Adam Hall, Luke Jansen, Ethan Paslowski, Paige Ross, & Christopher Utigard

File:Saturn's Rings PIA03550.jpg

Figure: Saturn's Rings (Artist's Concept) Source: http://photojournal.jpl.nasa.gov/catalog/PIA03550 Permission: Public Domain (Courtesy of Wikimedia Commons)

Figure: Jupiter Smyrna Louvre Source: https://commons.wikimedia.org/wiki/File:Jupiter_Smyrna_Louvre_Ma13.jpg Permission: Public Domain (Courtesy Wikimedia Commons)

Introduction

In Roman mythology, there is a tale in which Jupiter, the king of gods, overthrows his tyrannical father, Saturn. In doing so, Jupiter causes Saturn to release all the sons he had eaten in his paranoia that his children would eventually depose him.1 Today, this folklore is more accurate than Roman mythologists could have ever realized. Following the discovery of the telescope and the age of space flight, Saturn has revealed more “sons” to astronomers in the form of moons. On Monday, October 7, 2019, the International Astronomical Union’s Minor Planer Centre announced that Saturn had deposed Jupiter as the reigning moon-count champion of the solar system.2 Saturn, also known as the ringed planet, achieved this title through the discovery of 20 moons by astronomers working with the Subaru Telescope in Hawaii.

The newly discovered moons are quite small and distant from Saturn; however, these “estranged children” are if profound importance to the study of astronomy. There is much yet to be understood about the nature of reality and the study of cosmology. Even today, scientists continue to puzzle over the rate of expansion of the universe and its enormous size, the existence of dark matter and dark energy, the composition of quantum foam, and much more. Although these small moons may appear irrelevant to such existential questions, it is important to note that the history of the solar system is a crucial testing ground for any theory of how this or other solar systems may have formed. The amalgam of this knowledge is essential to our understanding of the universe and plays a critical role in determining the fundamental laws of reality. The story of these moons spans roughly 400 years, from the earliest known iteration of the telescope to such technological marvels as the Subaru Telescope, and some crucial spacecraft in between. Advancements in technology have played a crucial role in this narrative.

This paper will investigate how advances in ground-based and space probe technology led to the recent discovery of Saturn’s additional 20 moons. To accomplish this, there will be a brief look at the history of Saturnian observation before delving into two branches of principle technological developments: the first being the Subaru Telescope in Hawaii; and the second being the Cassini Spacecraft which plunged into Saturn, to its demise on September 15, 2017.3 Finally, there is consideration dedicated to how these technologies resulted in the discovery of the newfound Saturnian moons.

File:Galileo telescope replica.jpg

Figure: Galileo Telescope Replica Source: https://commons.wikimedia.org/wiki/File:Galileo_telescope_replica.jpg?fbclid=IwAR38qITRmdqckhTnthjsJhve_d90Tu8hDo4O83c7u0WeGF-XxiL4ijDm1E8 Permission: Creative Commons (Courtesy of Wikimedia Commons)

Background

The first telescope and the numerous updated versions since, played a massive role in the discovery of the new moons. The 17th century invention created a parade of early astronomers – Galileo Galilei, Giovanni Cassini, William Herschel, and many others – that trained their telescopes on the ringed-planet, observing, recording, and sharing their findings with the astronomical community.4 Over the next three hundred years, their collective reports unmasked a variety of Saturnian features ranging from ring characteristics to the identification of various individual moons and their orbits, and in the case of Titan, Saturn’s largest moon, even a confirmation of its atmosphere.5

Nevertheless, these telescopic discoveries only accounted for eight of the 82 currently known moons. At the time, the principle obstruction was in the size and sophistication of the telescopes. Consider, for instance, that Galileo, using a telescope with an eight-times magnification, was unable to observe the rings of Saturn with his telescope, and thus, mistook the planet’s oblong shape for a deformity.6 Saturn’s rings require roughly 20-times magnification for observation. As such, they remained invisible until Christiaan Huygens trained a telescope of sufficient magnification upon the planet.7

Accordingly, the next crucial advance was telescopic photography. In the 19th century, astronomers began the practice of stellar photography, and in 1899, were able to identify a ninth moon: Phoebe.8 It would not be until 1966, about 67 years later, that another moon, Janus, would be discovered. Confirmation of this tenth moon was not realized until 1978.9 By this time, means of discovery had drifted into space travel. In the late 1970s, the Voyager 1 spacecraft was already on its way across the solar system.10 Through observations and photography of its own, Voyager 1 was able to initially raise the total moon count to 17.11 Careful reviews of the Voyager 1’s archival images revealed an additional moon, Pan, which was discovered in 1990.11

Technological Advancement #1: The Subaru Telescope

Figure: Mauna Kea Subaru Source: https://commons.wikimedia.org/wiki/File:MaunaKea_Subaru.jpg Permission: Creative Commons (Courtesy of Wikimedia Commons)

The first of two crucial innovations in technology that allowed for the discovery of Saturn’s newfound 20 moons was the creation of the Subaru Telescope. The telescope was built by astronomers seeking to explore the unknowns of outer space and increase the base of knowledge of the universe.12  The Subaru Telescope has enabled the expansion of the observation of the galaxy, allowing astronomers to investigate planetary systems further.12 Through observation and data collection provided by the Subaru Telescope, scientists aim to determine the origins of life and provide a view of the universe far wider than ever before seen.12

Location, Location, Location

Image result for mauna kea map

Figure: Map of Mauna Kea Source: https://commons.wikimedia.org/wiki/File:Location_Mauna_Kea.svg Permission: Public Domain (Courtesy of Wiki Commons)

The location of the Subaru Telescope plays a major role in its advanced imaging capabilities which allowed for the discovery of Saturn’s new moons. It is located on the summit of Mauna Kea, a dormant volcano on the Big Island of Hawaii.12 The top of Mauna Kea is an isolated peak that protrudes above most of the Earth’s weather systems, which means the air pressure is only two-thirds of that of the sea level.12 Clouds typically form below the summit where an inversion layer, which is a sudden increase in temperature, keeps the clouds from rising to the summit.12 Because Hawaii is isolated from any other landmass, trade winds blow smoothly over the islands, and there are few cities to pollute its dark skies.12 The location has been recognized as one of the best astronomical observing sites because of these distinct features; it has also been defined as an irreplaceable natural and cultural resource for scientific discovery.12

The Features

The technology of the Subaru Telescope is as revolutionary as it was pivotal in the discovery of the new moons. The discovery of Saturn’s 20 minuscule moons was enabled by the Subaru Telescope’s advanced imaging technology.13 The Subaru Telescope is an optical, infrared telescope. Infrared ins one of many types of radiation present on the electromagnetic spectrum; it has a longer wavelength than visible light and cannot be seen with the human eye.14 The telescope has a wide field imaging capability which is 200-times greater than that of the Hubble Space Telescope.12 Wide-field imaging is different from regular field imaging because it uses a wide-aperture lens to capture the image rather than a standard width lens.15 The aperture of a telescope determines how much light will be collected by the device; as such, the higher the aperture, the greater the amount of light collected, and the better the image is produced.16 This feature, coupled with the telescope’s large mirror, sensitive charged-coupled device detectors, and its optimal location, gives the Subaru Telescope the ability to capture unique imaging.12

The Subaru Telescope also has other distinct features, including the fact that the primary mirror is equipped with an 8.2-meter aperture which is combined with an active support system that can preserve an unprecedented high mirror surface accuracy.12 The amount of light that is collected by a telescope is proportional to the square of its diameter; therefore, the Subaru Telescope’s large diameter is especially impressive. It allows for greater light gathering ability and enhances the resolution of images which results in brighter, more resolved pictures. These features were crucial in the discovery of Saturn’s new moons because it made the appearance of the objects clear enough to decipher. The active support system was also contributory to the telescope’s ability to spot the moons. It is equipped with many notable features. The enclosed design suppresses local atmospheric turbulence which allows for smoother travel and clearer images. The system’s tracking mechanism is exceptionally precise which results in sharper pictures. This success is due to the prevention of drifting, which causes “smearing” of objects across the image frame.17

File:Subaru Telescope under daylight.jpg

Figure: Subaru Telescope Under Daylight Source: https://en.wikipedia.org/wiki/File:Subaru_Telescope_under_daylight.jpg Permission: Creative Commons (Courtesy of Wikimedia Commons)

The Subaru Telescope also undergoes constant fine-tuning to ensure it has the highest resolving power possible, thus, producing sharper views of the features being observed.12 The telescope also comes equipped with a computer-controlled support system that keeps the smooth, single-piece primary mirror in shape.12 The mirror’s cylindrical shape enclosure minimizes air turbulence.12 Finally, the Subaru Telescope’s linear motors ensure that it is driven smoothly and accurately.12 The combination of the telescope’s unique features and impressive design allowed the device to capture high-quality images of Saturn’s new moons.

The Future of the Device

Despite the Subaru Telescope’s innovative technology and first-class image gathering ability, there are still improvements to be made. Astronomers intend to upgrade the adaptive optic system by adding actuators; this alteration will increase the telescope’s efficiency under poor visibility conditions and improve it for use at shorter wavelengths.18 They also plan to introduce a laser guide star system, which will hopefully allow the telescope to view a greater number of observable objects.18  The new adaptive optics system will demand a bright guide star near the observation target to allow the measurement of disturbances in wavelength.18 The concept behind the laser guide system is to provide astronomers with an artificial guide star when a natural guide star is missing.18  The objective of implementing these improvements is to allow the bulk of the sky to be observed and accessible from Mauna Kea.18  As discussed, the Subaru Telescope and its many features were vital in the discovery of the new moons. The telescope’s advanced technology allowed astronomers the first look at faint spots of light which were hypothesized to be additional moons.19 These intriguing points of light and computer techniques allowed multiple years of telescope imagining data to be analyzed. In turn, this examining enabled astronomers to confirm that the 20 dots of light were orbiting Saturn.19

Technological Advancement #2: The Cassini Spacecraft

The second of the two critical innovations in technology that enabled the discovery of Saturn’s additional moons was the Cassini spacecraft. The most recent discoveries mark a momentous leap forward in space exploration. Improvements in technology have allowed scientists to record multiple years of telescope images which in combination present a clear enough image to confirm the new moons.19 Accompanying the innovation of the telescope, was the Cassini-Huygens Mission. Previous missions, such as the Voyager flyby in the 1970s and the Pioneer flyby in the 1980s, introduced rough drafts of Saturn’s moons.20  However, neither of these flybys was as focused and extensive as the Cassini spacecraft, as they did not have the capability on board to latch onto Saturn’s orbit.21 During its many years in Saturn’s orbit, the Cassini spacecraft viewed previously undetermined moons and aided knowledge relating to the known objects.22

File:Voyager spacecraft.jpg

Figure: Voyager Spacecraft Source: https://en.wikipedia.org/wiki/File:Voyager_spacecraft.jpg Permission: Public Domain (Courtesty of Wikipedia)

The History of the Mission

On October 15, 1997, the Cassini spacecraft was launched as part of the Cassini-Huygens mission.23 The spacecraft was the first of its kind dedicated to observing Saturn and its surrounding system.24 Its namesake is Giovanni Cassini, the astronomer responsible for discovering four of Saturn’s moons, including Lapethus, in 1671; Rhea in 1672; Tethys, in 1686, and Dione, in 1684.24 The Cassini-Huygens mission combined three major space agencies: the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Italian Space Agency (ASI).25 Designed to explore Saturn’s rings and moons, with a special focus on Titan, the mission came at the cost of 3.3 billion US dollars.24  The spacecraft was launched on October 15, 1996, however, the mission did not commence until July 1, 2004.24 Prior to the Cassini launch, there were 18 confirmed moons orbiting Saturn.26 During the spacecraft's travel, 13 more moons were confirmed via Earth-based telescopes.27

The Cassini Spacecraft’s Visit

Image result for cassini spacecraft

Figure: Cassini Spacecraft Source: https://commons.wikimedia.org/wiki/File:Cassini_spacecraft_raw_uncompressed.png Permission: Public Domain (Courtesy of Wiki Commons)

Upon its arrival, the Cassini spacecraft used its new-age technology to discover two new moons: Methone and Pallene.28 Before the mission’s first year ended, it uncovered a third new moon, Polydeuces.24 November 2016 through April 2017, the Cassini spacecraft encountered and confirmed four smaller moons: Atlas, Daphnis, Pan, and Pandora.24 These seven moons are included in the twenty newly confirmed moons. The spacecraft was left to orbit Saturn for over a decade, during which it was able to observe the planet’s moons.29 The records of observation were used to improve the accuracy of information about the understanding of the moons’ relationship with Saturn’s rings.30

The Technology Behind the Success of the Mission

The Cassini spacecraft was equipped with advanced technology, including several instruments with the ability to view wavelengths of light and energy.31 The spacecraft used optical remote sensing for a variety of tasks, such as calculating measurements from far away, determining the quantity and composition of dust particles, as well as assessing the strength of plasma and radio waves.32 Simply phrased, remote sensing is measuring a characteristic from a distance, like radar reading the speed of a passing vehicle.33 The sensing component of the spacecraft is composed of a composite infrared spectrometer, an imaging science subsystem, an ultraviolet imaging spectrograph, and a visible and infrared mapping spectrometer.34 The instruments used to study Saturn’s environment, including dust, plasma, and magnetic fields, were the Cassini plasma spectrometer, a cosmic dust analyzer, an ion and neutral mass spectrometer, a magnetometer, a magnetospheric imaging instrument, and radio and plasma wave science.35 Additionally, the Cassini spacecraft used radio waves to map the atmosphere and determine the mass of the moons. Its radar, and radio science subsystem were used to unveil the surface of Titan.20 Essentially, the use and combination of these advanced scientific features on the space vessel were able to confirm the accuracy of images provided by other means, such as ground-based telescopes.

The findings made possible by this technology have an important context in modern astronomy. For example, the data collected provides evidence that some of the moons’ characteristics make them potentially habitable. The information harnessed from the Cassini-Huygens mission has also encouraged future endeavors in search of other solar systems.24 In conclusion, the Cassini-Huygens mission is linked to the discovery of Saturn’s 20 newly discovered moons as it was responsible for confirming the existence of seven of them.36 The cutting-edge technology onboard the spacecraft was able to provide scientists with enough accurate information and imaging to justify the confirmation of nearly half of the new moons.

Artist's concept of Cassini and Saturn

Figure: Artist's concept of Cassini and Saturn Source: https://www.nasa.gov/mission_pages/cassini/media/cassini-071204.html?fbclid=IwAR11ok0uMRIAebH3DpUlSQyxwN8021D1hQ-mtOqOQ-uaoSG4JmFGN4uLbBo Permission: Public Domain (Courtesy of NASA)

The Moons of Saturn

As explained, the combination of two technologies, the Subaru Telescope and the Cassini spacecraft, has contributed to a deeper understanding of Saturn’s moons. This insight of the moons sheds light on many questions surrounding their existence: where did they come from, why did scientists not see them before, and are there more moons out there? The following content will address these concerns and provide an explanation for the importance of their discovery.

How Are Moons Created?

In general, moons are created through the compaction of debris, such as comets or asteroids, captured by a planet’s gravity.37 Astronomers, such as Scott Shepard of the Carnegie Institute for Science, propose that these moons were created from impacts with Saturn. Sheppard and his colleagues theorize that the moon clusters formed from larger satellites captured by Saturn shortly after its formation.38 The parent bodies were then broken up over time by collisions which created the moon fragments now seen by astronomists.39  Scientists also note that due to their proximity from Saturn, it is likely that these moons were formed more recently, even in the past 100 million years, than the rest of the solar system.40

Why Did Scientists Not See Them Before?

These newly discovered moons were previously undetected due to their size. Measuring around three miles wide, these satellites were too small to be seen with past telescopes. As mentioned, the Subaru Telescope was only able to discover them because of its excellent light-gathering and resolving power and the Cassini spacecraft because of its ability to travel to proximity. It is also important to note that these moons barely fell into the realm of the Subaru telescope’s detection limit.38 As such, recent research suggests that there may be as many as 100 moons orbiting Saturn, but many are even smaller, under one kilometer wide, and unable to be detected by current telescope technology.39

This image from NASA's Cassini spacecraft captured five of Saturn's moons. Moons visible in this view: Janus; Pandora; Enceladus, Mimas & Saturn's second largest moon, Rhea.

Figure: Group Portrait Source: https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12797 Permission: Public Domain (Courtesy of NASA)

All About the Moons

The batch of 20 new moons falls into two categories of orbit: retrograde and prograde. Seventeen of the moons orbit Saturn in retrograde, while the other three circle the planet in prograde.38 Retrograde means that the moon’s orbit follows the opposite direction of Saturn’s rotation, whereas prograde means that they travel in the same direction as the planet’s rotation.41 The moons are also divided further into satellite groups. Saturn’s moons are organized into three satellite groups based on the direction and inclination of their orbit: the Norse Group, which orbit in retrograde; the Inuit Group, which orbit in prograde at inclinations between 40 and 50 degrees; and the Gallic Group, which also orbit in prograde but at inclinations between 35 and 40 degrees.42 The group of seventeen fit into the Norse Group. Then two of the remaining three are part of the Inuit Group with the last belonging to the Gallic Group.38 To date, the twenty new moons remain unnamed but will be labeled with a culturally appropriate name according to which group they fall under.

Are There More Moons Out There?

Considering how Shepard and his team were able to make a similar moon discovery related to Jupiter last year, using the same technology, it is likely that astronomers will continue to uncover more objects orbiting the solar system.43  These types of discoveries have a tremendous impact on the scientific community, as they can answer questions about how planets were formed and how they have evolved. For example, moons can indicate what collisions took place in the formation of the solar system.38  More specifically, Saturn’s moons are of interest to astronomers because they can collect material from Saturn’s rings and magnetosphere, which is a region of the planet that is magnetically charged.30 The composition of a moon can also tell astronomers more about the materials present in our solar system.

As a result of this discovery and others, there are currently three missions in progress: NASA’s Europa Clipper, NASA’s Dragonfly mission, and the ESA’s JUICE mission.38 The Europa Clipper is due to launch in 2025 and will arrive at Jupiter’s moon, Europa, by 2030.44 These missions, like the Cassini-Huygens mission, will be used to collect information on the compositions of moons surrounding the giant planets: Titan, the largest moon orbiting Saturn; and Europa, and the icy moons, circling Jupiter.45

Space, Future World, Planet, Fantasy, Universe, Science

Figure: Space Future Source: https://pixabay.com/photos/space-future-world-planet-fantasy-3953457/ Permission: Creative Commons (Courtesy of Pixabay)

Conclusion

The past half-century has seen an unprecedented explosion of Saturnian knowledge due to rapid innovation in telescope and spaceflight technologies.  As discussed, the Subaru Telescope contributed to spotting the new moons, as its excellent light-gathering ability and high resolving power enabled it to see further and clearer than previous telescopes. The Cassini spacecraft’s proximity and specialized stellar photography instruments provided the partial confirmation of the new moons. Accordingly, the discovery of these 20 new moons is vital to astronomy because it can provide astronomers information as to how the solar system formed, what types of materials are present surrounding Saturn, and insight as to how to improve the technologies to see even further. This information illuminates the history of the solar system like never before, yet new questions continue to arise and multiply. Still, the great success of these technologies will serve to guide the three missions in progress and many subsequent endeavors. Hopefully, in another half-century, astronomers will be publishing new discoveries being made with technologies created in the future based on the telescopes and spacecraft used today which will make questions like those discussed in this paper seem as outdated as Galileo’s observations.

 

References

1 New World Encyclopedia, Jupiter (Mythology), https://www.newworldencyclopedia.org/entry/Jupiter_(mythology) (Accessed 5 November 2019)

2 W. Dunham, Saturn is the solar system's 'moon king,' with 20 more spotted, https://www.reuters.com/article/us-space-saturn/saturn-is-the-solar-systems-moon-king-with-20-more-spotted-idUSKBN1WO2VD  (Accessed 5 November 2019)

3 EarthSky, Goodbye, Cassini!, https://earthsky.org/space/cassini-finale-sept-15-2017-how-to-follow-online (Accessed 21 November 2019)

4 N. English, Chronicling the Golden Age of Astronomy, (Springer International Publishing, 2018), p. 35

5 N. Redd, Titan: Facts About Saturn's Largest Moon, https://www.space.com/15257-titan-saturn-largest-moon-facts-discovery-sdcmp.html (Accessed 21 November 2019)

6 NASA, Galileo's Observations of the Moon, Jupiter, Venus and the Sun, https://solarsystem.nasa.gov/news/307/galileos-observations-of-the-moon-jupiter-venus-and-the-sun/ (Accessed 5 November 2019)

7 P. Louwman, Christiaan Huygens and his telescopes, (Springer Netherlands, 2004), p. 103-114

8 M. Williams, The moons of Saturn, https://phys.org/news/2015-09-moons-saturn.html (Accessed 6 November 2019)

9 NASA, Janus, https://solarsystem.nasa.gov/moons/saturn-moons/janus/in-depth/ (Accessed 5 November 2019)

10 NASA, Planetary Voyage, https://voyager.jpl.nasa.gov/mission/science/planetary-voyage/ (Accessed 21 November 2019)

11 NASA, Fact Sheet: The Voyager Planetary Mission, https://voyager.jpl.nasa.gov/frequently-asked-questions/fact-sheet/ (Accessed 6 November 2019)

12 Subaru Telescope, Subaru Telescope: The Challenge, https://subarutelescope.org/Introduction/overview.html (Accessed 6 November 2019)

13 Subaru Telescope, Subaru Telescope: Basic Design, https://subarutelescope.org/Introduction/outline.html (Accessed 6 November 2019)

14 NASA, Tour of the Electromagnetic Spectrum, https://science.nasa.gov/ems/07_infraredwaves (Accessed 10 November 2019)

15 A. Pavuluri, Astrophotography 101: Getting Started With Wide Field Astrophotography, https://www.firstpost.com/tech/news-analysis/astrophotography-101-getting-started-with-wide-field-astrophotography-4052261.html (Accessed 21 November 2019)

16 T. Vorenkamp, Understanding Exposure, Part 2: Aperture, https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-exposure-part-2-aperture (Accessed 10 November 2019)

17 Telescopes Plus, Computerized Go To and GPS Telescopes, https://www.telescopesplus.com/blogs/helpful-information/18961988-computerized-goto-and-gps-telescopes (Accessed 19 November 2019)

18 Subaru Telescope, AO System, https://www.subarutelescope.org/Introduction/instrument/AO.html (Accessed 5 November 2019)

19 M. Greshko, Discovery of 20 new moons gives Saturn a solar system record, https://www.nationalgeographic.com/science/2019/10/discovery-20-new-moons-gives-saturn-solar-system-record/ (Accessed 4 November 2019)

20 NASA, Cassini, https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/ (Accessed 7 November 2019)

21 W. Harwood, Saturn Orbit Insertion is a time of nervous anticipation, https://www.spaceflightnow.com/cassini/040612soi.html (Accessed 21 November 2019)

22 S. Bates, With 20 new moons, Saturn now has the most of any solar system planet, https://www.sciencenews.org/article/20-new-moons-saturn-now-most-any-solar-system-planet (Accessed 5 November 2019)

23 NASA, Mission to Saturn: Cassini-Huygens, https://www.jpl.nasa.gov/missions/cassini-huygens/ (Accessed 20 November 2019)

24 E. Howell, Cassini-Huygens: Exploring Saturn's System, https://www.space.com/17754-cassini-huygens.html (Accessed 7 November 2019)

25 I. Muiller-Wodarg, C. Griffith, E. Lellouch, and T. Cravens, Titan: Interior, Surface, Atmosphere, and Space Environment, (Cambridge University Press, 2014) p. 1

26 NASA, Cassini Mission Press Kit, https://www.jpl.nasa.gov/news/press_kits/cassini.pdf (Accessed 21 November 2019)

27 N. Redd, Saturn's Moons: Facts About the Ringed Planet's Satellites, https://www.space.com/20812-saturn-moons.html (Accessed 20 November 2019)

28 J. Rogerson, Understanding Saturn, its rings, and its moons: The Cassini-Huygens Mission, https://ingeniumcanada.org/channel/articles/understanding-saturn-its-rings-and-its-moons-the-cassini-huygens-mission (Accessed 19 November 2019)

29 B. Resnick, NASA crashed the $4 billion Cassini spacecraft into Saturn. It was awesome., https://www.vox.com/science-and-health/2017/9/13/16294502/cassini-finale-2017-saturn-rings-crash-nasa (Accessed 19 November 2019)

30 NASA, Saturn Moons, https://solarsystem.nasa.gov/moons/saturn-moons/overview/?page=0&per_page=40&order=name+asc&search=&placeholder=Enter+moon+name&condition_1=38%3Aparent_id&condition_2=moon%3Abody_type%3Ailike (Accessed 7 November 2019)

31 ESA, Cassini-Huygens, https://sci.esa.int/web/cassini-huygens/-/34954-instruments (Accessed 20 November 2019)

32 L. Spilker, Passage to a Ringed World, (NASA, 1997) p. 101

33 Natural Resources Canada, Fundamentals of Remote Sensing, https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/earthsciences/pdf/resource/tutor/fundam/pdf/fundamentals_e.pdf (Accessed 10 November 2019)

34 NASA, Visible and Infrared Mapping Spectrometer (VIMS), https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/visible-and-infrared-mapping-spectrometer/ (Accessed 20 November 2019)

35 NASA, Ion and Neutral Mass Spectrometer (INMS), https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/ion-and-neutral-mass-spectrometer/ (Accessed 19 November 2019)

36 E. Howell, Cassini's 13 Greatest Discoveries During Its 13 Years at Saturn, https://www.space.com/38142-cassini-greatest-saturn-discoveries.html (Accessed 20 November 2019)

37 ESA, ESA – Space for Kids – Moons, https://www.esa.int/kids/en/learn/Our_Universe/Planets_and_moons/Moons (Accessed 7 November 2019)

38 M. Greshko, Discovery of 20 new moons gives Saturn a solar system record, https://www.nationalgeographic.com/science/2019/10/discovery-20-new-moons-gives-saturn-solar-system-record/ (Accessed 7 November 2019)

39 M. Dunn, Discovery of 20 new moons puts Saturn ahead of Jupiter, https://www.kcbd.com/2019/10/07/discovery-new-moons-puts-saturn-ahead-jupiter/ (Accessed 7 November 2019)

40 L. Shekhtman, 10 Things: Unsolved Mysteries of Saturn's Moons – NASA Solar System Exploration, https://solarsystem.nasa.gov/news/911/10-things-unsolved-mysteries-of-saturns-moons/ (Accessed 7 November 2019)

41 Merriam-Webster, Definition of RETROGRADE, https://www.merriam-webster.com/dictionary/retrograde (Accessed 7 November 2019)

42 M. Wall, 20 New Moons Found Around Saturn, Snagging Satellite Record from Jupiter, https://www.space.com/saturn-20-newfound-moons-naming-contest.html (Accessed 7 November 2019)

43 Carnegie Institute for Science, A dozen new moons of Jupiter discovered, including one “oddball”, https://carnegiescience.edu/news/dozen-new-moons-jupiter-discovered-including-one-%E2%80%9Coddball%E2%80%9D (Accessed 7 November 2019)

44 B. Dunbar, Europa Clipper’s Mission to Jupiter’s Icy Moon Confirmed, https://www.nasa.gov/feature/europa-clippers-mission-to-jupiter-s-icy-moon-confirmed/ (Accessed 7 November 2019)

45 C. Choi, Jupiter: Our Solar System's Largest Planet, https://www.space.com/7-jupiter-largest-planet-solar-system.html (Accessed 20 November 2019)

copy The Technology Behind the Discovery of Saturn’s 20 New Moons

Posted on by

 Adam Hall, Luke Jansen, Ethan Paslowski, Paige Ross, & Christopher Utigard

File:Saturn's Rings PIA03550.jpg

Figure: Saturn’s Rings (Artist’s Concept) Source: http://photojournal.jpl.nasa.gov/catalog/PIA03550 Permission: Public Domain (Courtesy of Wikimedia Commons)

Figure: Jupiter Smyrna Louvre Source: https://commons.wikimedia.org/wiki/File:Jupiter_Smyrna_Louvre_Ma13.jpg Permission: Public Domain (Courtesy Wikimedia Commons)

Introduction

In Roman mythology, there is a tale in which Jupiter, the king of gods, overthrows his tyrannical father, Saturn. In doing so, Jupiter causes Saturn to release all the sons he had eaten in his paranoia that his children would eventually depose him.1 Today, this folklore is more accurate than Roman mythologists could have ever realized. Following the discovery of the telescope and the age of space flight, Saturn has revealed more “sons” to astronomers in the form of moons. On Monday, October 7, 2019, the International Astronomical Union’s Minor Planer Centre announced that Saturn had deposed Jupiter as the reigning moon-count champion of the solar system.2 Saturn, also known as the ringed planet, achieved this title through the discovery of 20 moons by astronomers working with the Subaru Telescope in Hawaii.

The newly discovered moons are quite small and distant from Saturn; however, these “estranged children” are if profound importance to the study of astronomy. There is much yet to be understood about the nature of reality and the study of cosmology. Even today, scientists continue to puzzle over the rate of expansion of the universe and its enormous size, the existence of dark matter and dark energy, the composition of quantum foam, and much more. Although these small moons may appear irrelevant to such existential questions, it is important to note that the history of the solar system is a crucial testing ground for any theory of how this or other solar systems may have formed. The amalgam of this knowledge is essential to our understanding of the universe and plays a critical role in determining the fundamental laws of reality. The story of these moons spans roughly 400 years, from the earliest known iteration of the telescope to such technological marvels as the Subaru Telescope, and some crucial spacecraft in between. Advancements in technology have played a crucial role in this narrative.

This paper will investigate how advances in ground-based and space probe technology led to the recent discovery of Saturn’s additional 20 moons. To accomplish this, there will be a brief look at the history of Saturnian observation before delving into two branches of principle technological developments: the first being the Subaru Telescope in Hawaii; and the second being the Cassini Spacecraft which plunged into Saturn, to its demise on September 15, 2017.3 Finally, there is consideration dedicated to how these technologies resulted in the discovery of the newfound Saturnian moons.

File:Galileo telescope replica.jpg

Figure: Galileo Telescope Replica Source: https://commons.wikimedia.org/wiki/File:Galileo_telescope_replica.jpg?fbclid=IwAR38qITRmdqckhTnthjsJhve_d90Tu8hDo4O83c7u0WeGF-XxiL4ijDm1E8 Permission: Creative Commons (Courtesy of Wikimedia Commons)

Background

The first telescope and the numerous updated versions since, played a massive role in the discovery of the new moons. The 17th century invention created a parade of early astronomers – Galileo Galilei, Giovanni Cassini, William Herschel, and many others – that trained their telescopes on the ringed-planet, observing, recording, and sharing their findings with the astronomical community.4 Over the next three hundred years, their collective reports unmasked a variety of Saturnian features ranging from ring characteristics to the identification of various individual moons and their orbits, and in the case of Titan, Saturn’s largest moon, even a confirmation of its atmosphere.5

Nevertheless, these telescopic discoveries only accounted for eight of the 82 currently known moons. At the time, the principle obstruction was in the size and sophistication of the telescopes. Consider, for instance, that Galileo, using a telescope with an eight-times magnification, was unable to observe the rings of Saturn with his telescope, and thus, mistook the planet’s oblong shape for a deformity.6 Saturn’s rings require roughly 20-times magnification for observation. As such, they remained invisible until Christiaan Huygens trained a telescope of sufficient magnification upon the planet.7

Accordingly, the next crucial advance was telescopic photography. In the 19th century, astronomers began the practice of stellar photography, and in 1899, were able to identify a ninth moon: Phoebe.8 It would not be until 1966, about 67 years later, that another moon, Janus, would be discovered. Confirmation of this tenth moon was not realized until 1978.9 By this time, means of discovery had drifted into space travel. In the late 1970s, the Voyager 1 spacecraft was already on its way across the solar system.10 Through observations and photography of its own, Voyager 1 was able to initially raise the total moon count to 17.11 Careful reviews of the Voyager 1’s archival images revealed an additional moon, Pan, which was discovered in 1990.11

Technological Advancement #1: The Subaru Telescope

Figure: Mauna Kea Subaru Source: https://commons.wikimedia.org/wiki/File:MaunaKea_Subaru.jpg Permission: Creative Commons (Courtesy of Wikimedia Commons)

The first of two crucial innovations in technology that allowed for the discovery of Saturn’s newfound 20 moons was the creation of the Subaru Telescope. The telescope was built by astronomers seeking to explore the unknowns of outer space and increase the base of knowledge of the universe.12  The Subaru Telescope has enabled the expansion of the observation of the galaxy, allowing astronomers to investigate planetary systems further.12 Through observation and data collection provided by the Subaru Telescope, scientists aim to determine the origins of life and provide a view of the universe far wider than ever before seen.12

Location, Location, Location

Image result for mauna kea map

Figure: Map of Mauna Kea Source: https://commons.wikimedia.org/wiki/File:Location_Mauna_Kea.svg Permission: Public Domain (Courtesy of Wiki Commons)

The location of the Subaru Telescope plays a major role in its advanced imaging capabilities which allowed for the discovery of Saturn’s new moons. It is located on the summit of Mauna Kea, a dormant volcano on the Big Island of Hawaii.12 The top of Mauna Kea is an isolated peak that protrudes above most of the Earth’s weather systems, which means the air pressure is only two-thirds of that of the sea level.12 Clouds typically form below the summit where an inversion layer, which is a sudden increase in temperature, keeps the clouds from rising to the summit.12 Because Hawaii is isolated from any other landmass, trade winds blow smoothly over the islands, and there are few cities to pollute its dark skies.12 The location has been recognized as one of the best astronomical observing sites because of these distinct features; it has also been defined as an irreplaceable natural and cultural resource for scientific discovery.12

The Features

The technology of the Subaru Telescope is as revolutionary as it was pivotal in the discovery of the new moons. The discovery of Saturn’s 20 minuscule moons was enabled by the Subaru Telescope’s advanced imaging technology.13 The Subaru Telescope is an optical, infrared telescope. Infrared ins one of many types of radiation present on the electromagnetic spectrum; it has a longer wavelength than visible light and cannot be seen with the human eye.14 The telescope has a wide field imaging capability which is 200-times greater than that of the Hubble Space Telescope.12 Wide-field imaging is different from regular field imaging because it uses a wide-aperture lens to capture the image rather than a standard width lens.15 The aperture of a telescope determines how much light will be collected by the device; as such, the higher the aperture, the greater the amount of light collected, and the better the image is produced.16 This feature, coupled with the telescope’s large mirror, sensitive charged-coupled device detectors, and its optimal location, gives the Subaru Telescope the ability to capture unique imaging.12

The Subaru Telescope also has other distinct features, including the fact that the primary mirror is equipped with an 8.2-meter aperture which is combined with an active support system that can preserve an unprecedented high mirror surface accuracy.12 The amount of light that is collected by a telescope is proportional to the square of its diameter; therefore, the Subaru Telescope’s large diameter is especially impressive. It allows for greater light gathering ability and enhances the resolution of images which results in brighter, more resolved pictures. These features were crucial in the discovery of Saturn’s new moons because it made the appearance of the objects clear enough to decipher. The active support system was also contributory to the telescope’s ability to spot the moons. It is equipped with many notable features. The enclosed design suppresses local atmospheric turbulence which allows for smoother travel and clearer images. The system’s tracking mechanism is exceptionally precise which results in sharper pictures. This success is due to the prevention of drifting, which causes “smearing” of objects across the image frame.17

File:Subaru Telescope under daylight.jpg

Figure: Subaru Telescope Under Daylight Source: https://en.wikipedia.org/wiki/File:Subaru_Telescope_under_daylight.jpg Permission: Creative Commons (Courtesy of Wikimedia Commons)

The Subaru Telescope also undergoes constant fine-tuning to ensure it has the highest resolving power possible, thus, producing sharper views of the features being observed.12 The telescope also comes equipped with a computer-controlled support system that keeps the smooth, single-piece primary mirror in shape.12 The mirror’s cylindrical shape enclosure minimizes air turbulence.12 Finally, the Subaru Telescope’s linear motors ensure that it is driven smoothly and accurately.12 The combination of the telescope’s unique features and impressive design allowed the device to capture high-quality images of Saturn’s new moons.

The Future of the Device

Despite the Subaru Telescope’s innovative technology and first-class image gathering ability, there are still improvements to be made. Astronomers intend to upgrade the adaptive optic system by adding actuators; this alteration will increase the telescope’s efficiency under poor visibility conditions and improve it for use at shorter wavelengths.18 They also plan to introduce a laser guide star system, which will hopefully allow the telescope to view a greater number of observable objects.18  The new adaptive optics system will demand a bright guide star near the observation target to allow the measurement of disturbances in wavelength.18 The concept behind the laser guide system is to provide astronomers with an artificial guide star when a natural guide star is missing.18  The objective of implementing these improvements is to allow the bulk of the sky to be observed and accessible from Mauna Kea.18  As discussed, the Subaru Telescope and its many features were vital in the discovery of the new moons. The telescope’s advanced technology allowed astronomers the first look at faint spots of light which were hypothesized to be additional moons.19 These intriguing points of light and computer techniques allowed multiple years of telescope imagining data to be analyzed. In turn, this examining enabled astronomers to confirm that the 20 dots of light were orbiting Saturn.19

Technological Advancement #2: The Cassini Spacecraft

The second of the two critical innovations in technology that enabled the discovery of Saturn’s additional moons was the Cassini spacecraft. The most recent discoveries mark a momentous leap forward in space exploration. Improvements in technology have allowed scientists to record multiple years of telescope images which in combination present a clear enough image to confirm the new moons.19 Accompanying the innovation of the telescope, was the Cassini-Huygens Mission. Previous missions, such as the Voyager flyby in the 1970s and the Pioneer flyby in the 1980s, introduced rough drafts of Saturn’s moons.20  However, neither of these flybys was as focused and extensive as the Cassini spacecraft, as they did not have the capability on board to latch onto Saturn’s orbit.21 During its many years in Saturn’s orbit, the Cassini spacecraft viewed previously undetermined moons and aided knowledge relating to the known objects.22

File:Voyager spacecraft.jpg

Figure: Voyager Spacecraft Source: https://en.wikipedia.org/wiki/File:Voyager_spacecraft.jpg Permission: Public Domain (Courtesty of Wikipedia)

The History of the Mission

On October 15, 1997, the Cassini spacecraft was launched as part of the Cassini-Huygens mission.23 The spacecraft was the first of its kind dedicated to observing Saturn and its surrounding system.24 Its namesake is Giovanni Cassini, the astronomer responsible for discovering four of Saturn’s moons, including Lapethus, in 1671; Rhea in 1672; Tethys, in 1686, and Dione, in 1684.24 The Cassini-Huygens mission combined three major space agencies: the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Italian Space Agency (ASI).25 Designed to explore Saturn’s rings and moons, with a special focus on Titan, the mission came at the cost of 3.3 billion US dollars.24  The spacecraft was launched on October 15, 1996, however, the mission did not commence until July 1, 2004.24 Prior to the Cassini launch, there were 18 confirmed moons orbiting Saturn.26 During the spacecraft’s travel, 13 more moons were confirmed via Earth-based telescopes.27

The Cassini Spacecraft’s Visit

Image result for cassini spacecraft

Figure: Cassini Spacecraft Source: https://commons.wikimedia.org/wiki/File:Cassini_spacecraft_raw_uncompressed.png Permission: Public Domain (Courtesy of Wiki Commons)

Upon its arrival, the Cassini spacecraft used its new-age technology to discover two new moons: Methone and Pallene.28 Before the mission’s first year ended, it uncovered a third new moon, Polydeuces.24 November 2016 through April 2017, the Cassini spacecraft encountered and confirmed four smaller moons: Atlas, Daphnis, Pan, and Pandora.24 These seven moons are included in the twenty newly confirmed moons. The spacecraft was left to orbit Saturn for over a decade, during which it was able to observe the planet’s moons.29 The records of observation were used to improve the accuracy of information about the understanding of the moons’ relationship with Saturn’s rings.30

The Technology Behind the Success of the Mission

The Cassini spacecraft was equipped with advanced technology, including several instruments with the ability to view wavelengths of light and energy.31 The spacecraft used optical remote sensing for a variety of tasks, such as calculating measurements from far away, determining the quantity and composition of dust particles, as well as assessing the strength of plasma and radio waves.32 Simply phrased, remote sensing is measuring a characteristic from a distance, like radar reading the speed of a passing vehicle.33 The sensing component of the spacecraft is composed of a composite infrared spectrometer, an imaging science subsystem, an ultraviolet imaging spectrograph, and a visible and infrared mapping spectrometer.34 The instruments used to study Saturn’s environment, including dust, plasma, and magnetic fields, were the Cassini plasma spectrometer, a cosmic dust analyzer, an ion and neutral mass spectrometer, a magnetometer, a magnetospheric imaging instrument, and radio and plasma wave science.35 Additionally, the Cassini spacecraft used radio waves to map the atmosphere and determine the mass of the moons. Its radar, and radio science subsystem were used to unveil the surface of Titan.20 Essentially, the use and combination of these advanced scientific features on the space vessel were able to confirm the accuracy of images provided by other means, such as ground-based telescopes.

The findings made possible by this technology have an important context in modern astronomy. For example, the data collected provides evidence that some of the moons’ characteristics make them potentially habitable. The information harnessed from the Cassini-Huygens mission has also encouraged future endeavors in search of other solar systems.24 In conclusion, the Cassini-Huygens mission is linked to the discovery of Saturn’s 20 newly discovered moons as it was responsible for confirming the existence of seven of them.36 The cutting-edge technology onboard the spacecraft was able to provide scientists with enough accurate information and imaging to justify the confirmation of nearly half of the new moons.

Artist's concept of Cassini and Saturn

Figure: Artist’s concept of Cassini and Saturn Source: https://www.nasa.gov/mission_pages/cassini/media/cassini-071204.html?fbclid=IwAR11ok0uMRIAebH3DpUlSQyxwN8021D1hQ-mtOqOQ-uaoSG4JmFGN4uLbBo Permission: Public Domain (Courtesy of NASA)

The Moons of Saturn

As explained, the combination of two technologies, the Subaru Telescope and the Cassini spacecraft, has contributed to a deeper understanding of Saturn’s moons. This insight of the moons sheds light on many questions surrounding their existence: where did they come from, why did scientists not see them before, and are there more moons out there? The following content will address these concerns and provide an explanation for the importance of their discovery.

How Are Moons Created?

In general, moons are created through the compaction of debris, such as comets or asteroids, captured by a planet’s gravity.37 Astronomers, such as Scott Shepard of the Carnegie Institute for Science, propose that these moons were created from impacts with Saturn. Sheppard and his colleagues theorize that the moon clusters formed from larger satellites captured by Saturn shortly after its formation.38 The parent bodies were then broken up over time by collisions which created the moon fragments now seen by astronomists.39  Scientists also note that due to their proximity from Saturn, it is likely that these moons were formed more recently, even in the past 100 million years, than the rest of the solar system.40

Why Did Scientists Not See Them Before?

These newly discovered moons were previously undetected due to their size. Measuring around three miles wide, these satellites were too small to be seen with past telescopes. As mentioned, the Subaru Telescope was only able to discover them because of its excellent light-gathering and resolving power and the Cassini spacecraft because of its ability to travel to proximity. It is also important to note that these moons barely fell into the realm of the Subaru telescope’s detection limit.38 As such, recent research suggests that there may be as many as 100 moons orbiting Saturn, but many are even smaller, under one kilometer wide, and unable to be detected by current telescope technology.39

This image from NASA's Cassini spacecraft captured five of Saturn's moons. Moons visible in this view: Janus; Pandora; Enceladus, Mimas & Saturn's second largest moon, Rhea.

Figure: Group Portrait Source: https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12797 Permission: Public Domain (Courtesy of NASA)

All About the Moons

The batch of 20 new moons falls into two categories of orbit: retrograde and prograde. Seventeen of the moons orbit Saturn in retrograde, while the other three circle the planet in prograde.38 Retrograde means that the moon’s orbit follows the opposite direction of Saturn’s rotation, whereas prograde means that they travel in the same direction as the planet’s rotation.41 The moons are also divided further into satellite groups. Saturn’s moons are organized into three satellite groups based on the direction and inclination of their orbit: the Norse Group, which orbit in retrograde; the Inuit Group, which orbit in prograde at inclinations between 40 and 50 degrees; and the Gallic Group, which also orbit in prograde but at inclinations between 35 and 40 degrees.42 The group of seventeen fit into the Norse Group. Then two of the remaining three are part of the Inuit Group with the last belonging to the Gallic Group.38 To date, the twenty new moons remain unnamed but will be labeled with a culturally appropriate name according to which group they fall under.

Are There More Moons Out There?

Considering how Shepard and his team were able to make a similar moon discovery related to Jupiter last year, using the same technology, it is likely that astronomers will continue to uncover more objects orbiting the solar system.43  These types of discoveries have a tremendous impact on the scientific community, as they can answer questions about how planets were formed and how they have evolved. For example, moons can indicate what collisions took place in the formation of the solar system.38  More specifically, Saturn’s moons are of interest to astronomers because they can collect material from Saturn’s rings and magnetosphere, which is a region of the planet that is magnetically charged.30 The composition of a moon can also tell astronomers more about the materials present in our solar system.

As a result of this discovery and others, there are currently three missions in progress: NASA’s Europa Clipper, NASA’s Dragonfly mission, and the ESA’s JUICE mission.38 The Europa Clipper is due to launch in 2025 and will arrive at Jupiter’s moon, Europa, by 2030.44 These missions, like the Cassini-Huygens mission, will be used to collect information on the compositions of moons surrounding the giant planets: Titan, the largest moon orbiting Saturn; and Europa, and the icy moons, circling Jupiter.45

Space, Future World, Planet, Fantasy, Universe, Science

Figure: Space Future Source: https://pixabay.com/photos/space-future-world-planet-fantasy-3953457/ Permission: Creative Commons (Courtesy of Pixabay)

Conclusion

The past half-century has seen an unprecedented explosion of Saturnian knowledge due to rapid innovation in telescope and spaceflight technologies.  As discussed, the Subaru Telescope contributed to spotting the new moons, as its excellent light-gathering ability and high resolving power enabled it to see further and clearer than previous telescopes. The Cassini spacecraft’s proximity and specialized stellar photography instruments provided the partial confirmation of the new moons. Accordingly, the discovery of these 20 new moons is vital to astronomy because it can provide astronomers information as to how the solar system formed, what types of materials are present surrounding Saturn, and insight as to how to improve the technologies to see even further. This information illuminates the history of the solar system like never before, yet new questions continue to arise and multiply. Still, the great success of these technologies will serve to guide the three missions in progress and many subsequent endeavors. Hopefully, in another half-century, astronomers will be publishing new discoveries being made with technologies created in the future based on the telescopes and spacecraft used today which will make questions like those discussed in this paper seem as outdated as Galileo’s observations.

 

References

1 New World Encyclopedia, Jupiter (Mythology), https://www.newworldencyclopedia.org/entry/Jupiter_(mythology) (Accessed 5 November 2019)

2 W. Dunham, Saturn is the solar system’s ‘moon king,’ with 20 more spotted, https://www.reuters.com/article/us-space-saturn/saturn-is-the-solar-systems-moon-king-with-20-more-spotted-idUSKBN1WO2VD  (Accessed 5 November 2019)

3 EarthSky, Goodbye, Cassini!, https://earthsky.org/space/cassini-finale-sept-15-2017-how-to-follow-online (Accessed 21 November 2019)

4 N. English, Chronicling the Golden Age of Astronomy, (Springer International Publishing, 2018), p. 35

5 N. Redd, Titan: Facts About Saturn’s Largest Moon, https://www.space.com/15257-titan-saturn-largest-moon-facts-discovery-sdcmp.html (Accessed 21 November 2019)

6 NASA, Galileo’s Observations of the Moon, Jupiter, Venus and the Sun, https://solarsystem.nasa.gov/news/307/galileos-observations-of-the-moon-jupiter-venus-and-the-sun/ (Accessed 5 November 2019)

7 P. Louwman, Christiaan Huygens and his telescopes, (Springer Netherlands, 2004), p. 103-114

8 M. Williams, The moons of Saturn, https://phys.org/news/2015-09-moons-saturn.html (Accessed 6 November 2019)

9 NASA, Janus, https://solarsystem.nasa.gov/moons/saturn-moons/janus/in-depth/ (Accessed 5 November 2019)

10 NASA, Planetary Voyage, https://voyager.jpl.nasa.gov/mission/science/planetary-voyage/ (Accessed 21 November 2019)

11 NASA, Fact Sheet: The Voyager Planetary Mission, https://voyager.jpl.nasa.gov/frequently-asked-questions/fact-sheet/ (Accessed 6 November 2019)

12 Subaru Telescope, Subaru Telescope: The Challenge, https://subarutelescope.org/Introduction/overview.html (Accessed 6 November 2019)

13 Subaru Telescope, Subaru Telescope: Basic Design, https://subarutelescope.org/Introduction/outline.html (Accessed 6 November 2019)

14 NASA, Tour of the Electromagnetic Spectrum, https://science.nasa.gov/ems/07_infraredwaves (Accessed 10 November 2019)

15 A. Pavuluri, Astrophotography 101: Getting Started With Wide Field Astrophotography, https://www.firstpost.com/tech/news-analysis/astrophotography-101-getting-started-with-wide-field-astrophotography-4052261.html (Accessed 21 November 2019)

16 T. Vorenkamp, Understanding Exposure, Part 2: Aperture, https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-exposure-part-2-aperture (Accessed 10 November 2019)

17 Telescopes Plus, Computerized Go To and GPS Telescopes, https://www.telescopesplus.com/blogs/helpful-information/18961988-computerized-goto-and-gps-telescopes (Accessed 19 November 2019)

18 Subaru Telescope, AO System, https://www.subarutelescope.org/Introduction/instrument/AO.html (Accessed 5 November 2019)

19 M. Greshko, Discovery of 20 new moons gives Saturn a solar system record, https://www.nationalgeographic.com/science/2019/10/discovery-20-new-moons-gives-saturn-solar-system-record/ (Accessed 4 November 2019)

20 NASA, Cassini, https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/ (Accessed 7 November 2019)

21 W. Harwood, Saturn Orbit Insertion is a time of nervous anticipation, https://www.spaceflightnow.com/cassini/040612soi.html (Accessed 21 November 2019)

22 S. Bates, With 20 new moons, Saturn now has the most of any solar system planet, https://www.sciencenews.org/article/20-new-moons-saturn-now-most-any-solar-system-planet (Accessed 5 November 2019)

23 NASA, Mission to Saturn: Cassini-Huygens, https://www.jpl.nasa.gov/missions/cassini-huygens/ (Accessed 20 November 2019)

24 E. Howell, Cassini-Huygens: Exploring Saturn’s System, https://www.space.com/17754-cassini-huygens.html (Accessed 7 November 2019)

25 I. Muiller-Wodarg, C. Griffith, E. Lellouch, and T. Cravens, Titan: Interior, Surface, Atmosphere, and Space Environment, (Cambridge University Press, 2014) p. 1

26 NASA, Cassini Mission Press Kit, https://www.jpl.nasa.gov/news/press_kits/cassini.pdf (Accessed 21 November 2019)

27 N. Redd, Saturn’s Moons: Facts About the Ringed Planet’s Satellites, https://www.space.com/20812-saturn-moons.html (Accessed 20 November 2019)

28 J. Rogerson, Understanding Saturn, its rings, and its moons: The Cassini-Huygens Mission, https://ingeniumcanada.org/channel/articles/understanding-saturn-its-rings-and-its-moons-the-cassini-huygens-mission (Accessed 19 November 2019)

29 B. Resnick, NASA crashed the $4 billion Cassini spacecraft into Saturn. It was awesome., https://www.vox.com/science-and-health/2017/9/13/16294502/cassini-finale-2017-saturn-rings-crash-nasa (Accessed 19 November 2019)

30 NASA, Saturn Moons, https://solarsystem.nasa.gov/moons/saturn-moons/overview/?page=0&per_page=40&order=name+asc&search=&placeholder=Enter+moon+name&condition_1=38%3Aparent_id&condition_2=moon%3Abody_type%3Ailike (Accessed 7 November 2019)

31 ESA, Cassini-Huygens, https://sci.esa.int/web/cassini-huygens/-/34954-instruments (Accessed 20 November 2019)

32 L. Spilker, Passage to a Ringed World, (NASA, 1997) p. 101

33 Natural Resources Canada, Fundamentals of Remote Sensing, https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/earthsciences/pdf/resource/tutor/fundam/pdf/fundamentals_e.pdf (Accessed 10 November 2019)

34 NASA, Visible and Infrared Mapping Spectrometer (VIMS), https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/visible-and-infrared-mapping-spectrometer/ (Accessed 20 November 2019)

35 NASA, Ion and Neutral Mass Spectrometer (INMS), https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/ion-and-neutral-mass-spectrometer/ (Accessed 19 November 2019)

36 E. Howell, Cassini’s 13 Greatest Discoveries During Its 13 Years at Saturn, https://www.space.com/38142-cassini-greatest-saturn-discoveries.html (Accessed 20 November 2019)

37 ESA, ESA – Space for Kids – Moons, https://www.esa.int/kids/en/learn/Our_Universe/Planets_and_moons/Moons (Accessed 7 November 2019)

38 M. Greshko, Discovery of 20 new moons gives Saturn a solar system record, https://www.nationalgeographic.com/science/2019/10/discovery-20-new-moons-gives-saturn-solar-system-record/ (Accessed 7 November 2019)

39 M. Dunn, Discovery of 20 new moons puts Saturn ahead of Jupiter, https://www.kcbd.com/2019/10/07/discovery-new-moons-puts-saturn-ahead-jupiter/ (Accessed 7 November 2019)

40 L. Shekhtman, 10 Things: Unsolved Mysteries of Saturn’s Moons – NASA Solar System Exploration, https://solarsystem.nasa.gov/news/911/10-things-unsolved-mysteries-of-saturns-moons/ (Accessed 7 November 2019)

41 Merriam-Webster, Definition of RETROGRADE, https://www.merriam-webster.com/dictionary/retrograde (Accessed 7 November 2019)

42 M. Wall, 20 New Moons Found Around Saturn, Snagging Satellite Record from Jupiter, https://www.space.com/saturn-20-newfound-moons-naming-contest.html (Accessed 7 November 2019)

43 Carnegie Institute for Science, A dozen new moons of Jupiter discovered, including one “oddball”, https://carnegiescience.edu/news/dozen-new-moons-jupiter-discovered-including-one-%E2%80%9Coddball%E2%80%9D (Accessed 7 November 2019)

44 B. Dunbar, Europa Clipper’s Mission to Jupiter’s Icy Moon Confirmed, https://www.nasa.gov/feature/europa-clippers-mission-to-jupiter-s-icy-moon-confirmed/ (Accessed 7 November 2019)

45 C. Choi, Jupiter: Our Solar System’s Largest Planet, https://www.space.com/7-jupiter-largest-planet-solar-system.html (Accessed 20 November 2019)

A Ninth Planet In Our Solar System: Why Is Modern Astronomy Advocating For A Giant Body In The Kuiper Belt? (Giuseppe Liuzzi)

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“I thought they were eight!” – A recent discovery in astronomy may rewrite history books. Our solar system could, in fact, host a super-Earth hidden in the Kuiper Belt, a vast area past Neptune. This is leaving everyone baffled, including the faceless guy in this image. Retrieved from https://pixabay.com/illustrations/question-quiz-think-thinking-2004314/. Copyright 2019 by Tumisu

This website post is characterized by a scientific nature, and will scrutinize one of astronomy’s latest, most challenging research enterprises that has spawned an enormous amount of peer-reviewed papers and news article in the past three years, that is the probable existence of a giant, icy, remote planet located in the outer region of the solar system, named Planet 9.

Readers will be presented with a comprehensive, detailed, and up-to-date analysis of the data that has been accumulated to validate the hypothesis of a ninth planet, ever since the latter was announced in 2016. Furthermore, it will also lay out the methodologies that have been utilized to capture data, and how the latter has been evaluated and interpreted by astronomers who are actively engaged in finding direct evidence. The essence of the analysis will revolve around the following research question:

 

What is the role of Planet 9 within our solar system, what has scientific inquiry discovered about the ways in which it exerts an influences on it, and what could it mean for the past, present, and future of our solar neighborhood?

 

After an introduction providing a general overview of the history of the solar system, attention will be redirected to a specific outer region where Planet 9 is thought to be located in, called Kuiper Belt. A thorough review of the astronomical past of this outer zone will be offered, whereby a number of discoveries will be linked together until they ideologically formed a theoretical framework upon which considerations of a giant planet in that area began to be justified. The subsequent section will present a vast series of data available advocating for the existence of Planet 9, including its influences on the region hosting it and on the whole solar system. Successively, contrasting opinions about the research procedures utilized to gather evidence about it will be scrutinized, and alternative interpretations advocating for the non-existence of the newly-proposed celestial body will be discussed. Finally, a conceptualized analysis of the ways in which the presence of a ninth planet would hold beneficial connotations will conclude the essay.

INTRODUCTION: Space activist and entrepreneur Rick Tumlinson is a prominent figure in the cosmological community, on top of being a well-known advocate for the exploration and colonization of our solar system. One of his most notorious aphorisms states that “discovering new things that will tell us about the history of our solar system, help reveal the secrets of life, and continue blazing the trail that may someday be traveled by the rest of us”.1

Jamaican journalist and political activist Marcus Garvey, the founder of garveyism, an ideological movement which advocated for the empowerment and consolidation of African-American individuals in the early 20th century, declared on several occasions that “a people without the knowledge of their past history, origin and culture is like a tree without roots”.2 Civil rights movement leader and Christian minister Martin Luther King Jr. has often quoted the past and its pertinence in the moulding of the human condition, with apothegms such as “we are not makers of history. We are made by history”.3

It is not relevant whether or not one’s background is comprised of astronomical interests, aspirations for equal rights regardless of skin colour, or proneness toward a societal standardization whereby constitutional and legal rights are justly enforced for everybody. The common denominator uniting the vast majority of the influential characters which have galvanized millions of individuals around the globe, regardless of their ideological drives, is represented by the awareness that the more efficient, virtuous way to understand ourselves is to inquire about our history. When projecting this mindset onto the bigger, cosmogenetic picture, it is then imperative to scrutinize our solar system’s past in order to discern and eventually decipher the dilemmas comprising our existence.

The eight planets composing our solar system. The possibility of a ninth, remote, massive body lying past Neptune may change astronomical history as we know it. Retrieved from https://en.wikipedia.org/wiki/Solar_System#/media/File:Planets2013.svg. Copyright 2013 by WP

 

OUR STELLAR HOME: A BRIEF OVERLOOK ON THE HISTORY OF THE SOLAR SYSTEM: Scientific inquiry on the topic of how the solar system was formed has been going on for centuries, and specifically saw its intellectual boost as the result of the Copernican Hypothesis, which challenged the centennial Ptolemaic, geocentric model by describing Earth as a wandering planet orbiting the Sun. 4

Geocentrism speculated that Earth was at the center of the universe, and stellar objects would revolve about it. The copernican revolution saw instead heliocentrism as its pivotal mechanism, whereby the Sun’s gravitational force attracts celestial bodies in orbits which are proportional to the distance between the star and the body itself. Retrieved from https://commons.wikimedia.org/wiki/File:Geoz_wb_en.svg. Copyright 2008 by Niko Lang & Booyabazooka

The most widely accepted theory is the Nebular Hypothesis. 5 The theorem revolutionized cosmogony and was initially proposed in the 1700s as the result of the conjunct works of Kant, Swedenborg, and Laplace. This perspective advocates for the birth of planets in relation to the evolution of nebulous material. 6

According to the nebular hypothesis, our solar system originated from a Nebula, that is an interstellar cloud mainly comprised of gas and stellar dust, roughly 4.5 billion years ago. As millions of years went by, gravity eventually stimulated such nebula which began to condensate whilst forming different sections, or regions, presenting dissimilar degrees of density. The portions of the nebula characterized by denser material subsequently started amassing into more solid matter. This phase represents the birth of our solar system, which later led to the spawning of what we now experience as our Sun, planets, and moons.

A visual representation of how a nebula looks like. The one pictured here is the carina nebula. Retrieved from https://en.wikipedia.org/wiki/Nebula#/media/File:Hs-2009-25-e-full.jpg. Copyright 2009 by NASA, ESA, and the Hubble SM4 ERO Team

As gravity gradually applied its force to make the gas in those regions denser, the rotation of the gas itself started to increase. The positive correlation between these two factors provoked a phenomenon called Accretion, whereby the diffusion of the gas cloud moulded the aforementioned zones into a rotating disk which in turn started to gravitationally attract even more nearby matter of gaseous nature. Conservation of momentum, meanwhile, made the disk rotate at increasingly higher rates, a process which resulted in both increased internal pressure and heat. Accretion caused our solar system to be shaped like a plane, but most importantly is the first pivotal seed upon which our Sun was cosmologically conceived.

An artist’s representation of the accretion process as it is forming a baby star at its center. Retrieved from https://it.m.wikipedia.org/wiki/File:Artist%E2%80%99s_Impression_of_a_Baby_Star_Still_Surrounded_by_a_Protoplanetary_Disc.jpg. Copyright 2009 by ESO/L. Calçada

In fact, the Sun was formed in the most active phase of accretion where the majority of the condensed material was redirected toward the highly-spinning center of its disk, until a ball in its center began to take form. While this celestial object was accumulating most of the stellar material in its vicinity, and kept on heating up, the rest of the objects were still affected by the gravitational pull of the latter, hence they remained orbiting about it, though were able to escape its grip and avoided being absorbed. These stellar bodies flattened out into the vast zone surrounding the accretion disk, and originated the second pivotal seed of our solar system, that is a Protoplanetary Disk.

The protoplanetary disk is a vast formation of gas, surrounded by sparse and tiny amounts of dust, which orbits a newly-born star. Within the disk, matter is slowly directed inwards, and dust particles are progressively enlarged and solidified until they grow into small rocks. Protoplanetary disks are thought to be the precursors of what will later become larger and more massive planetesimals, a primitive versions of planets which diameters can reach hundreds of kilometers.

A computer-generated image of a protoplanetary disk. Within it, planets are slowly starting to form. Retrieved from https://en.m.wikipedia.org/wiki/File:Protoplanetary-disk.jpg. Copyright 2006 by NASA & Pat Rowlings

The Planetesimal Hypothesis, 7 therefore, explains how the material of the protoplanetary disk is gradually pulled together by the gravitational pull exerted by the main object at its center, in such a way that the gas and dust composing the disk is eventually stiffen into small chunks of pebbles which get larger and larger, until they transform into planets and moons. The newly-formed larger objects closer to the main star presented silicates and metals which originally came from the nebula itself, and were characterized by high boiling points that can solidify, making up the telluric composition of what we today know are the Sun’s closest sisters, that is Mercury, Venus, Earth, and Mars. Conversely, planetesimals that formed in the outer region of the accretion disk, which have been named Jupiter, Saturn, Uranus, and Neptune, were not as exposed to the solar radiation emanating from the center of the disk itself, hence presented more icy compounds than silicates and metal. As a consequence, they grew way larger than the inner planets because they also developed atmospheres capable of capturing and storing vast amounts of helium and hydrogen.

However, not all the gaseous and dusty material comprising the accretion disk eventually turned into planetesimals. Especially in the outer region farther away from the star, plenty of fragments and detritus accumulated in a number of zones. One of them is called Kuiper Belt, and represents the area which is supposedly hosting the object upon which the focal analysis of this paper will revolve around, that is Planet 9.

The final piece of the puzzle in the nebular hypothesis is how the Sun became the potent energy source with which planets have evolved, ending up in the differentiated terrestrial and atmospheric conformations they are characterized by. As accretion took place along millions of years, the levels of pressure and density of hydrogen at the center of its disk, where the Sun was formed, eventually became so enormous that the process of thermonuclear fusion was achieved. The Sun, which was called a protostar back then, saw a constant and gradual increase in pressure, density, and temperature, until an equilibrium between the outward thermal pressure and the weight of the material located above it and pressing downward, hence inward the object, had been reached. At that point, the star was balanced and thermonuclear reaction fully active. This process is called the Hydrostatic Balancing Of Stars. 8 This mechanisms represents the final phase in the formation of a solar system. Now that the Sun is stabilized and planets and moons have established their elliptical behaviours within the system, nature does its course; these celestial bodies evolve and mutate along billion of years, in reference to their proximity to the main star, to the configurations of the gaseous envelope surrounding their outer structure, and to the terrestrial composition of the principal materials they are comprised of.

This video, narrated by renowned professor Stephen Hawking, features a spectacular 3d reconstruction of the formation of the solar system through the utilization of CGI techniques (WordPress refused to embed it, so a direct link has been provided for the readers).

FAR AWAY, MYSTERIOUS, AND FASCINATING: THE KUIPER BELT MAY HOST ONE OF 21th CENTURY’S BIGGEST MYSTERIES: As discussed above, not all of the gas and dust within an accretion disk is pressurized enough to be remodeled into planetesimals, and if all goes well, into moons or planets afterwards. A portion of it is likely to be pushed farther from the center of the disk, and may later on assemble into outer, colder regions. In these areas, it is common to find asteroids and massive, icy bodies which still do not escape the Sun’s bending of the spacetime, slowly revolving about it.

An example of such space territories is the Kuiper Belt, a vast ring of frozen celestial bodies located outside our solar system’s farthest planet’s orbit, that is Neptune. 9 Relatively close to it we find Pluto, reclassified in 2006 to a Dwarf Planet, 10 a new typology of stellar objects which do not fully fit within the physical characteristics of a regular planet, especially in terms of dimensions and gravitational dominance. 11 Pluto was once called the ninth planet of our solar system, until it lost that prestigious title. The Kuiper Belt is comprised of a number of different objects, including dwarf planets Pluto, Eris, and Haumea, on top of several comets, ice, and floating rocks. As mentioned above, these objects are so far away from their maternal star that it may take them a very long time to complete a full orbit about the latter. For instance, Eris completes its orbit in 557 years. 12

Planetologist Alan Stern declared that “going to the Kuiper Belt is like an archaeological dig into the history of the solar system”. 13 Scrutinizing such a mysterious place, in fact, may lead cosmology to a more comprehensive understanding of the history of the solar system, and such enterprise is the main focal objective of the New Horizons spacecraft, which in 2015 reached past Pluto’s orbit, in an attempt to further investigate the Kuiper Belt area.

The largest objects comprising the Kuiper Belt. Retrieved from https://commons.wikimedia.org/wiki/File:TheKuiperBelt_75AU_Large.svg. Copyright 2006 by Eurocommuter

This video discusses 10 things to know about the Kuiper Belt area (WordPress refused to embed it, so a direct link has been provided for the readers).

PLANET 9 MAY BE OUT THERE: HISTORICAL LINKAGES ABOUT HOW IT WAS “DISCOVERED”: One year after New Horizons was launched, an astounding announcement was made by a group of astronomers: a giant, undiscovered planet may be orbiting in the Kuiper Belt zone, in the vicinity of Neptune. If we took a look at the history books, however, we would realize that speculations on massive body in such area have actually started roughly 200 years ago.

The first scientist to notice something was going on was Paris resident Bouvard, 14 who in 1820 was studying Uranus and noticed discrepancies between old recordings and new data of the planet’s position while engaged in its orbit. He came to the conclusion that another planet may be pulling it from its path, even if just slightly. Ever since such discoveries, the orbital behaviour of Uranus has appeared unconventional. Few decades later it was French mathematician Le Verrier who calculated the possibility of another planet past Uranus, until astronomer Galle sighted it, and was later named Neptune. The newly added eighth planet stimulated further curiosity in the field, and scientists were gradually more interested in what may be lying past it, predicting that a ninth planet could possibly exist in that area.

However, as more data was gathered by new telescopic technologies and spacecraft, a better understanding of the mathematical models and physics regulating the movements of the planets, moon, and objects in our system was achieved. According to these readings, the shifting and positioning of them was not atypical, and in 1993, after decades of speculations, the search for a giant ninth planet was abandoned due to the fact that no dissimilarities in the orbital and elliptical behaviours of stellar bodies in the outer region could be detected.

As analyses of the Kuiper Belt area kept accumulating data about that region, further scrutiny of Pluto made astronomers realize how vast and diversified such region was. This realization is what maintained scientists inspired about the possibility of other relevant bodies in the belt, and in 2003 a significant discovery was made, that is a massive body, later named 2003 VB12, which represented the most distant object ever seen by science orbiting our star. However, it was not a giant planet, but rather a small body later called Sedna with an extremely elongated orbit that made it complete a full revolution in about 10,000 years. Calculations about Sedna’s peculiar orbital behaviour is what continued whispering in astronomer’s ears that something massive was shaping the orbits of a number of objects in the Kuiper Belt. This was ulterior confirmation that something was exerting relevant gravitational pull, in fact three years earlier orbital analysis of object 2000 CR105 had already suggested that a Mars-sized planet may have slightly pulled it away from its Neptunian orbit. Interestingly enough, this discovery was classified as a miscalculation until Sedna was found, and scientists noted that both entities had been redirected in the same direction. 15

As more objects were being identified in the Kuiper Belt zone, and their elliptical movements were analyzed and compared, it became apparent that some of them exhibited orbital alignments that were tugged by something massive in the same direction of the aforementioned Sedna and 2000 CR105. After several computer simulations, four researchers announced in 2016 that a massive planet 10 times the size of Earth, located at about 600 astronomical units from the Sun, was likely to exist in the Kuiper Belt area. 16 They later named it Planet 9. 17

Mysterious and far away. As there are no direct observations of Planet 9, this artist’s representation is, for now, the most accurate image of it. Retrieved from https://en.wikipedia.org/wiki/File:Planet_nine_artistic_plain.png. Copyright 2016 by nagualdesign & Tom Ruen

HOW CAN WE PROVE IT? PLANET 9’s ACCUMULATED EVIDENCE AND ITS INFLUENTIAL BEHAVIOURS ON THE KUIPER BELT, AND POSSIBLY, ON THE WHOLE SOLAR SYSTEM: Hypothesizing about the existence of a ninth planet in our solar system is therefore, in sum, justified by observational and computational data pointing toward the presence of a giant body in the Kuiper Belt influencing the elliptical behaviour of some of the latter’s objects. Specifically, it is its gravitational influence on those objects, and surprisingly its potential side effects on the solar system, that are motivating astronomic research to maintain its interest focused on the outer section of our stellar backyard.

First and foremost, it appears that several of those objects are both pushed and pulled by the bending of spacetime caused by something comprised of huge mass, which has not been detected by modern telescopes yet. Planet 9’s influence is thought to mainly dictate the angular orbital demeanor of some trans-Neptunian objects (TNOs), and data points toward lower perihelion distances for the potential new planet that may cause angular restrictions for celestial objects in the Kuiper Belt zone denoted by perihelion distances longer than 40 astronomical units, and semi-major axes greater than 250 astronomical units. 17

Furthermore, the speculated characteristics of Planet 9 and its gravitational pull on nearby objects that have been computed during the last few years eventually led to the formulation of a mathematical model, which has resulted both in the gradual discovery of TNOs, 19 and in substantiated predictions about the latter’s orbital behaviours in the cold region hosting them. 20

Another piece of evidence which is interconnected to the previously discussed analysis of TNOs orbital demeanors results once again from the observation of some icy objects and dwarf planets, which orbits demonstrate a tendency of aggregating, or clustering together, due to the gravitational influence of something of massive proportions that must be located in their vicinity. 21

Observations of TNO’s featuring high inclination and semi-major axes being less than 100 astronomical units have also been put in the mix, as a possible result of Planet 9’s influence. Since these objects enter perpendicular orbits, they show low perihelia so that their orbits converge with those of Neptune. An encounter with a giant celestial body such as Planet 9 is predicted to be, may explain the lowering of such TNO’s semi-major axes to less than 100 astronomical units, where the object’s orbits is no longer influenced by the massive body. This would justify the orbits of some TNOs such as, for example, 2008 KV42. 22

Some TNOs’ orbits in the Kuiper Belt may be affected by Planet 9. In this visual representation, we can see the speculated orbital behaviour of such planet, and how it would intersect with other objects as they perform their normal revolutions. Retrieved from https://commons.wikimedia.org/wiki/File:Planet_nine-etnos_now.png. Copyright 2016 by Tomruen

Planet 9’s manipulations may not limit themselves to the Kuiper Belt region. According to recent scientific data and simulations, it may have a greater impact on the entire solar system itself, in the form of a six-degree tilt of the latter between the proportional plane of the system’s bigger planets and the solar equator. 23 This perspective emphasizes an evolutionary model of the inclination of the inner big planets’ plane in relation to Planet 9ʼs deducted mass and orbital components. The longitude of the ninth planet’s ascending node is supposedly connected to the longitude of the ascending node of the other inner planets’ plane, while also inhibiting the former’s longitude of the node on the ecliptic, that is the imaginary line indicating the path of the Sun as it appears to move over the course of one year. Conversely, some interpretations on the matter of the tilting of the solar system are more conservative and less invasive on the current body of knowledge, advocating for a mere one-degree tilt on the latter operated by Planet 9. 16

This video features a 16-minute interview with the two scientists who, in 2016, published a series of peer-reviewed journal articles advocating for the existence of Planet 9. This audio-visual document offers an interesting perspective on the ways in which evidence from the Kuiper Belt area has been processes and interpreted, coming directly from the main sources of what could be one of the 21th century’s biggest discoveries in the astronomy field (WordPress refused to embed it, so a direct link has been provided for the readers).

THE (SPECULATED) COMPOSITION AND BIOGRAPHY OF THE NINTH PLANET: Not much is known about the characteristics of Planet 9 besides its potential mass of five to ten times that of Earth, and the time that it should take it to perform a revolution about the Sun, that is roughly 10,000 to 20,000 years. The dearth of information is due to the absence of physical observations, and to the difficulties in properly locating it in the celestial sphere because of its supposedly extremely dim luminosity.

As far as its origins are concerned, yet again there is no certainty and most of the proposed hypotheses are essentially of speculative nature. While astronomers around the world are waiting for the launch of the James Webb Telescope in 2022, which will provide photographic evidence of the Kuiper Belt area thus definitely confirming or disproving the existence of Planet 9, along with analytical data on how and why it was formed, what is now at the public’s disposal is a number of theories on the factors which may have contributed to originate it.

A prominent theory has been recently advanced by one of the researchers who initially announced the probable existence of such giant body in the outer region, Michael Brown. The scientist affirms that Planet 9 may have formed alongside Neptune and should present an overall conformation very similar to the latter, though as the solar system evolved along million of years, it eventually got pushed farther away by gravitational forces, 24 to the remote and sunlight-free region known as Kuiper Belt.

PLANET 9 MAY NOT BE AS FASCINATING, BUT RATHER… DANGEROUS: Alternative views are less optimistic. A study published in 2019 advocates for the possibility that the variations of TNOs’ orbital behaviours may not be the result of a big planet’s influence on spacetime, but rather the effects of a primordial black hole of very small diametrical extension. 25

An episode of popular YouTube channel SciShow Space tackles the issue of Planet 9 possibly being a black hole in this riveting video (WordPress refused to embed it, so a direct link has been provided for the readers).

Moreover, other conjectures align themselves on the same frequency of pessimism. When the Sun will become a white dwarf in about seven billion years, our current physics model, Einstein’s general relativity, predicts that the inner planets will be sucked into its mass, while the bigger, more distant planets such as Uranus and Neptune will instead be pushed farther away at a safe distance from the galactic blast. Planet 9’s existence would change the solar system’s fate, leading to its entire demise. According to some researchers, the giant body would instead be attracted by the Sun’s explosion, heading inwards toward it, and thus exerting its gravitational pull on those outer planets which would follow it into collision with the star, hence to their death. 26 This process would result in the destruction of our entire solar system, or in the best case scenario, in its significant reduction to a mere one or two planets.

PLANET NINE OR PLANET NONE?: Contrasting opinions about the ninth planet are also directed toward perspectives promoting its non-existence. Some have proposed that the scientists that identified Planet 9 may simply have miscalculated the data related to unconventional TNOs by utilizing wrong detection techniques, and showed only a limited number of objects supposedly being affected by the giant body whereas according to mathematical models, more should be impacted by such massive entity. Others declared that they may even be the victims of detection bias, where the effects of a phenomenon are over- or under-estimated in order to fit a preordained model. 27

In addition, there is debate among the astronomical community about the orbits of some NTOs, as they represent one of the main arguments for the existence of Planet 9. The discoverers of the ninth planet advocate for such stellar body to cause the orbits of these NTOs to be clustered, but parallel surveys have not been able to detect these clustered orbits, and have instead shown that they are randomly distributed throughout the region. 28

PLANET 9 AND US: WHY ITS EXISTENCE IS RELEVANT TO OUR IDENTITY AS CITIZENS OF THE UNIVERSE: After having presented a thorough and meticulous examination of the evidence advocating for the existence of a ninth, giant, icy planet unhurriedly revolving our star without ever been physically spotted, readers may ask themselves whether or not the presence of another massive stellar body in human’s solar system may be momentous at all, and if it is, why would that be?

At the beginning of this online journey, I suggested that it is important to know our history as a mean to better understand ourselves. As a consequence, I advocated for the notion that inquiring about Planet 9 is essential to further establish the history of our solar system, hence of our astronomical past. Furthermore, I referred to a number of peer-reviewed, scientific material declaring that Planet 9’s influential attributes may extend not only to the region hosting it, but to the entire system itself, and possibly, even to the other giant planets comprising it when the latter will suffer the consequences of the Sun’s mutation into a deadly white dwarf. Apart from the repercussions of a ninth planet on the morphology of our solar neighborhood, there are a number of reasons why, should it be one day confirmed, it represents a relevant leap for mankind.

Firstly, its scientific corroboration would directly position itself into the history books, which will have to declare how another important planet in our solar system was discovered after taciturnity on the subject which has lasted for more than 170 years (or 85 if some readers still want to call Pluto a real planet).

Secondly, it would further demonstrate that our detection techniques to investigate the galaxy, such as telescopic imaging and spacecraft enterprises, represent a valid and efficient way to scrutinize even the most remote regions surrounding us, and that even if scientific consensus is often difficult to achieve, synchronized collaboration between parties from all over the world can produce enthralling revelations, regardless of the physical separation between us and the objects we want to investigate.

Thirdly, Planet 9’s confirmation would make our solar system a little more similar to other distant star systems astronomers have been scrutinizing for the last couple of decades. Some of these systems include planets orbiting distant stars (exoplanets) with masses that are at least ten times more massive than Earth. Until 2016, when the possibility of the existence of a ninth planet was announced, scientists were not granted with the chance to directly research them, due to the incredible distances separating us from them that our current technology cannot handle. Now that evidence points towards the presence of an exoplanet, or super-Earth in our solar neighborhood, direct observations of such mysterious entities would be possible, and in the near future, robots may even be sent on the surface of Planet 9, and astounding data would be relayed back to us, just like it is happening nowadays thanks to the rovers sent on Mars. The prospects of a confirmation and direct observation of Planet 9 would mould our universal identity as citizens of the universe, by possibly infusing a sense of humility and demureness, as we realize that our solar system may not be so special after all when compared to others, and that super Earths like the ninth planet are not peculiar to our neighbors only.

The search for Planet 9 continues, and it will be eventually be found. Or disproved. In the meantime, astronomers all over the world are keeping their eyes peeled (and their telescopes well aligned, as well). Retrieved from https://en.wikipedia.org/wiki/Astronomy#/media/File:USA.NM.VeryLargeArray.02.jpg. Copyright 2004 by Hajor

 

References:

1 Exploration: Process vs. Product, https://spacenews.com/exploration-process-vs-product/
2 Goodreads, https://www.goodreads.com/quotes/280448-a-people-without-the-knowledge-of-their-past-history-origin
3 Mayo, A., Mayo, A. J., & Nohria, N. In their time: The greatest business leaders of the twentieth century. Harvard Business Press. (2005).
4 Westman, R. S. The comet and the cosmos: Kepler, mästlin and the copernican hypothesis. In The Reception of Copernicus’ Heliocentric Theory (pp. 7-30). Springer, Dordrecht. (1973).
5 Moulton, F. R. On the evolution of the solar system. The Astrophysical Journal, 22, 165. (1905).
6 How Was the Solar System Formed? – The Nebular Hypothesis, https://www.universetoday.com/38118/how-was-the-solar-system-formed/
7 Brush, S. G. The origin of the planetesimal theory. Origins of Life, 8(1), 3-6. (1977).
8 Schwarzschild, K. On the equilibrium of the sun’s atmosphere. Nachrichten von der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Math.-phys. Klasse, 195, p. 41-53, 195, 41-53. (1906).
9 Levison, H. F., & Morbidelli, A. The formation of the Kuiper belt by the outward transport of bodies during neptune’s migration. Nature, 426 (6965), 419. (2003).
10 Why Isn’t Pluto a Planet Anymore?, https://www.space.com/why-pluto-is-not-a-planet.html
11 What Is A Dwarf Planet?, https://www.universetoday.com/72717/what-is-a-dwarf-planet/
12 NASA Science – Solar System Exploration, https://solarsystem.nasa.gov/planets/dwarf-planets/eris/in-depth/
13 On Pluto Time: Q&A with New Horizons Leader Alan Stern, https://www.space.com/30934-pluto-new-horizons-alan-stern-interview.html
14 Holman, M. J., & Payne, M. J. Observational constraints on planet nine: Astrometry of pluto and other trans-neptunian objects. The Astronomical Journal, 152(4), 80. (2016).
15 Morbidelli, A., & Levison, H. F. Scenarios for the origin of the orbits of the trans-neptunian objects 2000 CR105 and 2003 VB12 (sedna). The Astronomical Journal, 128(5), 2564. (2004).
16 Batygin, K., Adams, F. C., Brown, M. E., & Becker, J. C. The planet nine hypothesis. Physics Reports. (2019).
17 How we discovered Planet Nine, http://www.astronomy.com/magazine/2018/10/how-we-discovered-planet-nine
18 Cáceres, J., & Gomes, R. The influence of planet nine on the orbits of distant tnos: The case for a low-perihelion planet. The Astronomical Journal, 156(4), 157. (2018).
19 The Evidence for Planet Nine’s Existence I NOVA I PBS (YOUTUBE VIDEO), https://www.youtube.com/watch?v=hiJxgfBVGr8
20 New evidence in support of the Planet Nine hypothesis, https://www.eurekalert.org/pub_releases/2017-07/f-sf-nei071217.php
21 Brown, M. E., & Batygin, K. Observational constraints on the orbit and location of planet nine in the outer solar system. The Astrophysical Journal Letters, 824(2), L23. (2016).
22 Batygin, K., & Brown, M. E. Generation of highly inclined trans-neptunian objects by planet nine. The Astrophysical Journal Letters, 833(1), L3. (2016).
23 Gomes, R., Deienno, R., & Morbidelli, A. The inclination of the planetary system relative to the solar equator may be explained by the presence of Planet 9. The Astronomical Journal, 153(1), 27. (2016).
24 Planet Nine SHOCK: Astronomer reveals how Planet 9 was EJECTED from the solar system, https://www.express.co.uk/news/science/1130087/Planet-Nine-news-Planet-9-orbit-ejected-solar-system-Mike-Brown-Caltech
25 Scholtz, J., & Unwin, J. What if planet 9 is a primordial black hole?. arXiv preprint arXiv:1909.11090. (2019)
26 Was Planet Nine Found? Mysterious World Could Destroy Solar System (In Seven Billion Years), https://www.ibtimes.com/was-planet-nine-found-mysterious-world-could-destroy-solar-system-seven-billion-years-2409849
27 This Is Why Most Scientists Think Planet Nine Doesn’t Exist, https://www.forbes.com/sites/startswithabang/2018/09/14/this-is-why-scientists-think-planet-nine-doesnt-exist/#751176fb6e77
28 Sokol, J. New haul of distant worlds casts doubt on planet nine. (2017).

The Moon’s Effect on Ocean Tides

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By:Priscila Ferreira Da Silva, Robyn Bray, Shelby Kaczur, Bryant Mills-Sackney, Katelyn Finlay

Introduction 

The Moon is one of the most recognizable features in the sky. It has mesmerized and has been celebrated by human beings from different cultures throughout history. The moon has awakened the curiosity and interest of entire civilizations both due to its influence on our planet and for the mysteries that could be stored on its surface. Although the connection between the Earth and the Moon has not always been fully understood, the Moon has been meaningful to many cultures. As it turns out, science has demonstrated that the Moon likely has been vital to the existence of life on Earth, thus validating our natural fondness with the Moon

Tides are one particular aspect of the Earth-moon connection that science has been able to describe thoroughly, and such explanation had led to a more encompassing understanding that the moon is indispensable to the existence of life on Earth. The moon acts as a stabilizer of the Earth’s rotation, as if the moon was absent, the Earth would tilt as high as 85 degrees. The severity in the tilt of the Earth would cause the sun to shift from hovering over the equator to hovering over the North and South poles.1 The moon helps to center the Earth while it is spinning on its axial tilt, which is the reason we have a stable climate which allows for life to flourish, waters to flow and tides to occur.1

The moon’s gravity pulls the Earth toward itself, causing sea levels rise and fall, thus creating tides. Due to its proximity to the moon, water on the near side of the Earth is pulled more strongly towards the moon. In contrast, water on the far side of the Earth experiences the weakest gravitational pull from the moon. This effect causes water to bulge on both the near and far sides of the Earth, creating high tides in that region. On the other hand, water being drawn away from the oceans leads to low tides in that area. Therefore, as the Earth spins on its axis once a day, water at lower latitudes goes through two cycles of high and low tides. Since there is always a thinner layer of water at high latitudes near the north and south poles, these areas experience continual low tide, while the north and south poles experience low tide as a result of the water being mostly covered with ice over the surface of the Earth.

Below, we will present to you, information on the reasons tidal force from the moon exerts a great deal of influence on the Earth. The tidal force causes the tides to occur, it also causes Earth to maintain stability about its axis on rotation. We will demonstrate historical studies that have proposed explanations on tides, explain the mechanisms and effects of tidal cycles through Newton’s law of universal gravitation.

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Figure 1:The Earth and the Moon
Link: https://www.britannica.com/place/Moon/images-videos

What are Tides?

Tides are waves that move through the ocean causing the increases or decreases in water volumes along the coast lines. These volume changes are responses to changing forces due to the sun and the moon and the Earth’s continual rotation. The highest part of a wave is called a crest, and when waves reach a particular height it is called high tide. Thus low tide corresponds to the lowest part of the wave called the trough. The difference between high tide and low tide is thus called the tidal range.2

tide_diagram

Figure 2: Relative Positions of the Earth and the Moon During High and Low Tide. Link: https://en.wikibooks.org/wiki/Adventist_Youth_Honors_Answer_Book/Nature/Stars_-_Advanced_(General_Conference)

Historical Background on the Search for an Explanation of Tides

In 330 B.C, a Greek astronomer named Pytheas notice that different moons in the night sky seemed to have an effect on the oceans tides.3 While sailing from the Mediterranean Sea to the British Isle, Pytheas noticed that the tides and the movement of the ocean was somehow controlled by the moon. Pytheas also noticed that there were two tides per lunar day, and that the amplitude of the waves depended on the phases of the moon.3 Pytheas wrote about his discoveries, but his original work were lost. Nonetheless, Pytheas’ work was carried on as other scientists, such as Aristotle have quoted his work. These observations marked the advancement of Western research on tides.

Many other Greek astronomers followed Pytheas’ footsteps but no one was able to make sense of the tidal shifting for quite a long time. However, there were various attempts to understand the tides, some observations were valid and others not as relevant. For example, in the 13th century, a Persian Physician and Astronomer named Zakariya al-Qazwini wrote a book describing how the tides were formed claiming that the sun heated the water, causing the liquid to expand and that the moon was responsible for cooling the water down, causing the liquid to shrink.3 

Even the great Galileo (1564-1642) could not figure out the science behind tides. He believed that tides were produced because of the Earth’s rotation on its axis and the Earth’s rotation around the sun. These motions would set the ocean waters oscillating which would produce tides. The gravitational force of the moon on tides was not completely understood until Isaac Newton created the theory of gravity in the 17th century.

“I deduced that the forces which keep the planets in their orbs must be reciprocally as the squares of their distances from the centers about which they revolve, and thereby compared the force requisite to keep the moon in her orb with the force of gravity at the surface of the Earth and found them to answer pretty nearly.”
— Isaac Newton, 16664

So, How Do Tides Work?

The following section contains further information on how Newton’s law of universal gravitation explains the correlation between the Earth and the Moon.

It was in 1687, that Sir Isaac Newton explained to the world that tides occur because of water’s gravitational attraction to the sun and the moon. Newton’s law of universal gravitation states “the gravitational attraction that occurs between two objects is directly proportional to the product of their masses.” 5 This means the closer the objects are to one another the greater attraction these objects will incur. This is the root reason why the moon has the larger effect on tides, due to the fact that the moon is the closest object which is gravitationally attracted to the Earth and the ocean. The ocean does experiences gravitational attraction to the sun, but because the sun is farther away from the Earth its gravitational pull is less than the moon’s.

So while the Earth is spinning about on its axis, the oceans waters are kept in a state of equilibrium around the planet with the water being acted upon by Earth’s gravity and centrifugal force.6 As previously stated the moon has a strong gravitational pull which causes an alteration in the oceans and thus the tides. When the moon appears its gravitational attraction actually pulls the water towards the moon. This causes a bulge of water that gains force from Earth’s rotation about its axis, which is known as high tide. A high tide occurs on the side of the Earth directly facing the moon at any given time because of the gravitational force.7 The opposite is shown with low tides when the sun is out. Low tide occurs on the sides at 90 degree angles to the moon because the ocean is stretched over the Earth’s surface.8
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Figure 3:Forces That Influence the Tides
Link: http://scistand.com/2016/february-2016-history-moon/

Further Information 9

Predicting the Tides

High and low tides occur daily, generally twice a day (diurnal). However, these periods do not happen at the same time each day because the Moon takes slightly longer than a full day to line up again exactly with the same point on the Earth.10 Thus, the timing of high tides is staggered throughout the course of a month, about 24 hours and 50 minutes later than the one before it.11

Thus, the tides can’t be perfectly predicted by astronomical calculations that track the Sun and Moon. For greatest accuracy, tide prediction tables always integrate data from actual observation, often over a period of many years.

Why are Tides Important?

Tidal waves are a vital part of our ecosystems. Tidal waves cause smaller fish to gather together, making them easy prey for larger aquatic animals. Also, other organisms like coral reefs depend on ocean currents to deliver food to them. For without the consistent tidal movements stationary aquatic plants and unable to survive.  Thus the importance of Tides to our natural environment can not be overstated enough.12

Tides are also a very reliable source of renewable energy, because of the predictability of tidal waves. Tidal energy is still in its infancy as a renewable resource but scientists are working hard to harness the renewable energy caused by tidal waves in a larger commercial fashion. Below are the top four uses today for Tidal Energy.

Tidal Electricity – Like other forms of energy, the main usage of tidal energy is in the generation of electricity. Tidal energy is being used by the Rance Tidal Power Station in Brittany, France to generate 240 MW of tidal electricity. There are other plants in operation in Canada, China and Korea as well. The power generated from tidal energy is reliable as tides are generally uniform and predictable in nature.

Grain Mills –Tidal energy can be used for the mechanical crushing of grains in grain mills. The movement of turbines due to tidal energy is used in the crush grains. However, with the advents of fossil fuels, this usage of tidal energy has become quite low.

Energy Storage – By creating hydroelectric dams or tidal barrages (A tidal barrage is a dam-like structure used to capture the energy from masses of water moving in and out of a bay or river due to tidal forces) tidal energy can also be used and stored as a form of energy.

Protection – Tidal barrages can prevent damage to the coast or even cities during a high storm season by providing an easy transport method.13

As stated before, the Moon stabilizes the Earth’s rotation axis. Without the Moon, the Earth’s axis would oscillate, causing the Earth to face extreme temperature variation and daylight availability.1 The moon would be subject to the forces of other planets that also orbit around the Sun and pull the Earth in different directions. Thus, the Earth would be drawn by various forces over time, which would not be able to sustain life on Earth as we know it.

Conclusion 

The moon is thought to be one of the key reasons that Earth is a habitable planet, because it helps to center the Earth while it is spinning on its axial tilt, which is the reason we have a stable climate which allows for life to flourish, waters to flow and tides to occur. The phenomenon of tides had baffled generations of scientists, astronomers like Pytheas predicted the moon was the cause of these dramatic water movements. However, it was not until 1678 when Sir Isaac Newton explained gravitational attraction that people started to understand how important our moon really is. For it is the moon’s gravity is what causes sea levels to rise and fall.
References

1 N.Taylor Redd, “Earth Stabilizing Moon May be Unique Within Universe” 29 July 2011, http://www.space.com/12464-earth-moon-unique-solar-system-universe.html (19 October 2016).

2 USA. gov., n.d., “What Causes Tides?” http://scijinks.jpl.nasa.gov/tides/ (3 October 2016).

3 Martin Ekman, “A Concise History of the Theories of Tides, Precession-Nutation and Polar Motion,” 13 May 1993, http://www.afhalifax.ca/magazine/wp-content/sciences/vignettes/supernova/nature/MAREES/HistoireMarees.pdf (19 October 2016).

4 Matt Williams, “Who Discovered Gravity?” 28 Apr 2016, http://www.universetoday.com/53898/who-discovered-gravity/ (3 October 2016).

5 NOAA National Ocean Service Education “Tides and Water Levels,” 06 Oct 2016, http://oceanservice.noaa.gov/education/kits/tides/tides02_variations.html (2 November 2016).

6 Deborah Byrd, “Tides, and the pull of the moon and sun,” 7 Apr 2016, http://Earthsky.org/Earth/tides-and-the-pull-of-the-moon-and-sun#two-tides (2 October 2016).

7 Andrea Alfano, “How The Moon Affects Tides,” 31 Aug 2015, http://www.techtimes.com/articles/80715/20150831/moon-affects-tides.html (3 October 2016).

8 Charles Choi, “Moon Facts: Fun Information About the Earth’s Moon,” 19 Nov 2014, http://www.space.com/55-Earths-moon-formation-composition-and-orbit.html (18 October 2016).

9 Josh Clark, “How Do Tides Work?- Brain Stuff,” 17 Mar 2014, https://www.youtube.com/watch?v=5ohDG7RqQ9I (15 November 2016).

10 Moon Connection, “Apogee and Perigee of the Moon,” 2016, http://www.moonconnection.com/apogee_perigee.phtml (2 October 2016).

11 NOAA National Ocean Service, “What are Tides?” 6 Feb 2006, http://oceanservice.noaa.gov/facts/tides.html (19 October 2016).

12 NOAA National Ocean Service Education, “Tides and Water Levels” 25 March, 2008, http://oceanservice.noaa.gov/education/kits/tides/tides09_monitor.html (25 November 2016).

13 Abhishek Shah,“Uses of Tidal Energy – Tidal Electricity the Biggest One” 15 March 2011, http://www.greenworldinvestor.com/2011/03/15/uses-of-tidal-energy-tidal-electricity-the-biggest-one/( 10 November 2016).