Field Guide Study: Moons, Planets, and Beyong

FIELD GUIDE STUDY: MOONS, PLANETS, AND BEYOND Ariel Novak University of Alaska, Anchorage Professor Michelle Cullen ASTR 103: Solar System Astronomy

TABLE OF CONTENTS • Introduction: 1 • Constellations: 2-7 • Sun: 8, 9 • Moon: 10, 11 • Earth: 12, 13 • Terrestrial Planets: 14-19 • Gas Giants: 20-27 • Dwarf Planets: 28-33 • Comets: 34 • Asteroids: 35

INTRODUCTION Learn all about some of the constellations that are seen in the night sky, the sun and moon, the planets in our solar system, dwarf planets, the moons of other planets, comets, and asteroids in this field guide study! Each object we study reviews its physical properties, composition, size and distance, and missions that have already been conducted or are in the planning stages to learn more about these objects! As a bonus treat, you will learn accompanying astrology with these objects! Acknowledgements: I would like to acknowledge the Astronomy class and our professor, Michelle Cullen, for the successful completion of this Astronomy Field Guide Study. Page 1

INTRODUCTION TO CONSTELLATIONS Constellations are a group of stars that make an imaginary shape in the night sky. They are usually named after mythological characters, people, animals and objects. In different parts of the world, people have made up different shapes out of the same groups of bright stars. Asterisms are a small grouping of stars that do not make up one of the 88 complete constellations recognized by the International Astronomical Union. Source: (https://horoscopes.lovetoknow.com/about-astrology/constellations-zodiac. 2020). Sources: California Institute of Technology. What are constellations? 2020. http://coolcosmos.ipac.caltech.edu/ask/259-What-are- constellations Swinburne University of Technology. Asterism. 2020. http://astronomy.swin.edu.au/cosmos/A/Asterism Four constellations chosen: Taurus (Winter), Virgo (Spring), Scorpius (Summer), Capricornus (Fall). I chose these constellations because they are all zodiac constellations. I find the zodiac mythology very interesting and was excited to learn the myths associated with each of them. I specifically chose Virgo because that is my sign and I chose Scorpius because that is my husband’s and oldest son’s sign. Two of my four children are Capricorns and my other is a Taurus. Page 2

DE PERSEVERANTIA MALLEO Translation: Hammer of Persistence Myth: Common Name: The Hammer There was a woman who was blessed with a baby at a very young age. She was all alone and very fragile, but she was determined to give this baby the best life Source: (http://areios.herokuapp.com, 2020) she could. She worked very hard at multiple jobs with long hours for years to raise this baby by herself. When the child was two, the woman met her future Viewing The Hammer: You can see the Hammer of Persistence husband. The man vowed to care for and protect the mother and her child and constellation in January in the 1st Quadrant of the Northern Hemisphere. they had four beautiful children they shared together. The woman has continued It is located directly underneath the North Star. to work hard, even after meeting her husband, and earned herself a well-paying and respectful job. She works alongside her husband and they equally support their four children together. You can see the Hammer of Persistence constellation in the dead of winter as a reminder to always work hard and keep focused on what's important. This constellation has six stars for each member of the family and shines bright in the dark skies. Discovery: The Hammer was discovered in 1523 by the famous Polish astronomer, Nicolaus Copernicus. Special Stars: The star at the bottom of the hammer is Ariel, named after the woman in the myth. The next star in the constellation is Mark, named after the husband in the myth. Those two stars make up the handle on the hammer. The four remaining stars that make up the head of the hammer represent their four children. The parent stars are seen holding up their children to keep the hammer upright. Page 3

TAURUS Myth: When Zeus fell in love with the Phoenician Princess Europa, he transformed Translation: The Bull himself into a white bull with golden horns named Taurus. The princess admired Common Name: Taurus the bull and, when she sat on his back, he rose and headed for the sea. Zeus carried Europa all the way to the island of Crete, where he revealed his true Source: (https://www.thehoroscope.co/sign-articles/taurus-Taurus-Constellation- identity and lavished the princess with presents. Facts-29.html. 2014). Discovery: Viewing Taurus: You can see Taurus in the Northern Hemisphere. It is Taurus has been known since at least the Early Bronze Age, when it marked the seen from November to March, but the constellation's at its most visible Sun’s location during the spring equinox. It is seen in Greek and Egyptian in January. Taurus is best seen from latitude 90 degrees to -65 degrees. culture and was even dated back to the Babylon civilization. Taurus is located very close to Orion, just east of the constellation. Special Stars: The brightest star in Taurus is Aldebaran, which is the 14th brightest star in the sky. Aldebaran is part of the star group Hyades, which makes up the bull’s face. The other star group in the constellation is Pleiades, which consists of seven stars that make up the bull’s shoulder. In mythology, Pleiades represents the seven daughters of Atlas and Pleione. Sources: Future US Inc., Taurus Constellation: Facts About the Bull. 2018. https://www.space.com/17101-taurus-constellation.html). Constellation Guide, Taurus Constellation. 2020. (https://www.constellation- guide.com/constellation-list/taurus-constellation/). Page 4

VIRGO Myth: The constellation Virgo is usually associated with the Greek goddess of justice, Translation: Virgin Dike. Dike was the daughter of Zeus and Greek Titaness Themis. Virgo is Common Name: Virgo usually depicted with angel-like wings, with an ear of wheat in her left hand, marked by the bright star Spica. Dike lived in the Golden Age of mankind. She was born a mortal and placed on Earth to rule over human justice. Dike gave a speech to the entire race, warning them about the dangers of leaving behind the ideals of their predecessors and saying worse was yet to come. Then she flew to the mountains, turning her back on humans. When the Bronze and Iron Ages came and humans started warring among themselves, Dike left the Earth altogether, and flew to the heavens. Discovery: Virgo was first catalogued by Ptolemy in the 2nd Century, although it had played a role in Greek mythology prior to that. Source: (https://www.thehoroscope.co/sign-articles/virgo-Virgo-Constellation-Facts- Special Stars: 33.html. 2014). Virgo is the second largest constellation in the sky and has the most stars with planets (20) of any other constellation. The brightest star in the constellation is Spica. In addition to its stars, Virgo also contains 11 Messier objects. Viewing Virgo: Virgo is the second largest constellation in the sky and is Sources: located in the third quadrant of the southern hemisphere and can be seen Constellation Guide, Virgo Constellation. 2020. (https://www.constellation- guide.com/constellation-list/Virgo-constellation/). at latitudes between +80° and -80°. Page 5

SCORPIUS Myth: There are many versions of this myth in Greek mythology. One of the versions Translation: Scorpion is that Orion tried to ravish the goddess Artemis and she sent the scorpion to kill Common Name: Scorpius him. Scorpius killed Orion and Orion is now on the opposite side of the sky, fleeing from the scorpion. In ancient Greek times, the constellation Scorpius was Source: (https://www.thehoroscope.co/sign-articles/scorpio-Scorpio-Constellation- significantly larger and comprised of two halves, one with the scorpion’s body Facts-34.html. 2014). and the sting, and one containing the claws. The latter was called Chelae, or “claws.” In the first century BC, the Romans turned the claws into a separate Viewing Scorpion: Scorpion is best seen in the Southern Hemisphere constellation, Libra, the Scales. and is located near the center of the Milky Way. It is best seen between latitudes 40 degrees and -90 degrees. Discovery: Scorpius pre-dates the Greeks, and is one of the oldest constellations known. The Sumerians called it GIR-TAB, or “the scorpion,” about 5,000 years ago. Special Stars: Scorpion is home to a few bright stars and notable objects. Its brightest stars are Antares (one of the brightest stars in the sky) and Shaula. It also contains the Butterfly Cluster, the Ptolemy Cluster, Cat’s Paw Nebula, the Butterfly Nebula, and the War and Peace Nebula. Sources: Constellation Guide, Scorpio Constellation. 2020. (https://www.constellation- guide.com/constellation-list/Scorpio-constellation/). Page 6

CAPRICORNUS Myth: In Greek mythology, Capricornus was associated with the forest deity, Pan, who Translation: The Goat had the legs and horns of a goat. Pan was placed in the sky by Zeus in gratitude Common Name: Capricornus for his coming to the other gods’ rescue on several occasions. During the gods’ war with the Titans, Pan helped scare the Titans away by blowing his conch shell Source: (https://www.thehoroscope.co/sign-articles/capricorn-Capricorn- and he later warned the gods that Typhon, a monster sent by Gaia to fight the Constellation-Facts-37.html. 2014). gods, was approaching. He also suggested that the gods disguise themselves as animals until the danger passed. In another story, Capricornus is identified as Viewing Capricornus: Capricornus is one of the most faint Amalthea, the goat that suckled Zeus when he was an infant, hiding from his constellations in the sky, making it tricky to view. It lies in the 4th father Cronos. Cronos had devoured his other children, all future gods and quadrant of the southern hemisphere near Aquarius. It is best seen at goddesses, because of a prophecy that he would be overthrown by one of them. latitudes between 60 degrees and -90 degrees. Discovery: Capricornus was associated with myths dated in the 21st century B.C. It is recorded in ancient Babylonian and Sumerian records. Special Stars: The brightest star in Capricornus is Deneb Algedi, Delta Capricorni. There are five meteor showers associated with Capricornus: the Alpha Capricornids, the Chi Capricornids, the Sigma Capricornids, the Tau Capricornids, and the Capricorniden-Sagittarids. Sources: Constellation Guide, Capricornus Constellation. 2020. (https://www.constellation-guide.com/constellation-list/Capricornus- constellation/). Page 7

SOL Myth: Apollo was the son of Zeus (Jupiter) and Leto (Letona). He was the twin brother Translation: The Sun of the goddess Artemis. He was the god of the Sun, logic, and reason, and was Common Name: Sun also a fine musician and healer. Leto travelled all over Greece to find a place to give birth to Apollo. She finally Source: (https://www.space.com/22393-sun-magnetic-field-explained-infographic.html. 2013). came upon an island named Delos. The island agreed to allow the birth of Apollo if he in turn founded a temple on the island. Leto agreed, and when Apollo grew up, he changed Delos into a beautiful island. Apollo was known as the god who could foretell the future. His most famous sacred place was at Delphi, site of the Oracle of Delphi. Physical Properties of the Sun: The sun is the star of our solar system. Everything in the solar system revolves around the sun due to its gravitational pull. It dictates the weather in space, as well as the climates on all the planets. The sun’s atmosphere holds many layers, but the main ones are the photosphere, chromosphere, and the corona. The photosphere (closest layer to the sun) is where the sun’s energy is released into light. The chromosphere (middle layer from the sun) emits a red glow as hydrogen is being burned off. The corona (outer layer from the sun) appears as white streamers off the sun as ionized plumes flow outward into space. This becomes solar wind. The sun has an 11 year cycle that it goes through, the Solar Cycle. The sun’s magnetosphere contains two poles that flip during each solar cycle. The magnetosphere is so large and strong that it reaches out past our planets into interstellar space. It acts as a magnetic shield against charged particles and cosmic rays. See the image to the left for a graphic view of the sun’s magnetosphere. Page 8

SOL Missions to the Sun: NASA launched the Parker Solar Probe over a year and a half ago to study the Translation: The Sun sun. They started receiving their first stints of data at the end of 2019 and NASA Common Name: Sun announced their findings last month. They already knew that the sun's atmosphere held extremely high winds that were pushed all the way out through Source: (https://www.extremetech.com/extreme/305564-scientists-snap-closest- the solar system, greatly affecting the solar system's space weather. The Parker ever-view-of-the-sun. January 2020). Solar Probe picked up wind speeds of over 1 million miles per hour. One of the main goals of the probe is to pinpoint the mechanisms that send this wind all the way out in space. There have been noted disturbances in the solar wind that have spanned across decades of research. The probe will focus on these disturbances to try to discover the solar wind mechanisms. It is also known that these disturbances are pockets of relatively dense material that are large enough to completely collapse the Earth's magnetic field, if it were to come in contact with it. The Parker Solar Probe is a fascinating project that will provide scientists with tons of new data and help us learn more about our sun and how it effects the solar system, and consequently, the Earth. Sources: https://www.windows2universe.org/mythology/Definitions_gods/Apollo_def.ht ml. 2010. https://www.universetoday.com/94252/characteristics-of-the-sun/. March 2012. https://www.space.com/17160-sun-atmosphere.html. November 2017. https://www.space.com/22393-sun-magnetic-field-explained-infographic.html. September 2013. https://www.nasa.gov/feature/goddard/2019/revealing-the-physics-of-the-sun- with-parker-solar-probe. December 2019 Page 9

LUNA Myth: Luna was worshipped at the new and full moons. Her parents were the Titans Translation: Moon Hyperion and Theia; her brother was Helios, the sun god; her sister Common Name: The Moon was Eos (Dawn). She is often linked with Endymion, whom she loved and Other Names: Mona, Selene, Mwezi whom Zeus cast into eternal sleep in a cave on Mount Latmus; there, she visited him and became the mother of 50 daughters. Source: (https://solarsystem.nasa.gov/moons/earths-moon/overview/. 2020). Size and Distance: The Moon is 380,000 km from Earth and has a diameter of 3,474 km. Physical Properties of the Moon: The moon is 1/80th of the Earth in mass. It has very low gravity and is made up almost entirely of silicate rock and is nearly deplete of metals. In 2009, scientists discovered that ice is located at the lunar poles inside of deep craters, thought to have been brought there from asteroids hitting the moon and the water molecules becoming trapped and frozen in the deep craters where the sun doesn’t reach. The hemisphere that faces Earth is covered in dark mare, while the hemisphere that faces away from Earth is dominantly covered by highlands. The term mare, or maria in plural, means “sea” in Latin. This term is used to describe darker plains of lower elevation on the moon. They are huge basins containing lava flows. The highlands are primarily anorthosite, which is an igneous rock that is formed from slowly cooling lava, compared to the quick cooling lava in the mare. The moon also has many craters, which are caused by asteroids and meteoroids crashing into the moon’s surface. The moon has thousands of craters and is very susceptible to their damage to the lack of an atmosphere to protect itself. Page 10

LUNA Mission to the Moon – Apollo 12: The Apollo 12 was a successful mission led by NASA to the moon. They Translation: Moon Common Name: The Moon launched from Earth on November 14, 1969, landed on the surface of the moon Other Names: Mona, Selene, Mwezi on November 19, departed on November 20, and safely landed back on Earth on November 24, 1969. This mission marked the first time human explorers met a robotic device in space. It was also the first crewed lunar mission with science as the primary objective. They also proved that they can project the landing of a space craft by successfully landing 512 feet away from the Surveyor 3, the robotic space craft that landed on the moon two years prior. Two moon walks were conducted while on the moon’s surface, totaling 8 hours of time on the moon. They deployed the Apollo Lunar Surface Experiment Package (ALSEP), and they took photographs, investigated lunar soil mechanics, and collected samples of lunar rocks and debris from solar wind. They also collected samples along large craters, in hopes of learning about the interior of the moon. Sources: https://www.usatoday.com/story/news/nation-now/2017/10/23/why-doesnt- moon-have-better-name/792695001/. 2017. https://www.britannica.com/topic/Selene-Greek-and-Roman-mythology. 2020. https://www.discovermagazine.com/the-sciences/how-far-away-is-the-moon. 2011. https://courses.lumenlearning.com/astronomy/chapter/general-properties-of-the- moon/. 2020. https://www.britannica.com/science/mare-lunar-feature. 2020. This image shows an astronaut on the Apollo 12 mission working with http://www.pas.rochester.edu/~blackman/ast104/moon_surface.html. 2020. the Apollo 12 Lunar Module with the robotic spacecraft, Surveyor 3, in https://astronomy.swin.edu.au/~smaddiso/astro/moon/craters.html. 2010. the background. https://solarsystem.nasa.gov/missions/apollo-12/in-depth/. 2019. Page 11

EARTH Myth: In the beginning there was only chaos. Then out of the void appeared Erebus, the Other Names: Terra, Gaea unknowable place where death dwells, and Night. All else was empty, silent, endless, darkness. Then somehow Love was born bringing a start of order. From Source: (https://phys.org/news/2019-02-method-enables-view-earth-interior.html. 2019). Love came Light and Day. Once there was Light and Day, Gaea, the earth appeared. Size of the Earth, Mass, and Distance from the Sun: Earth’s equatorial radius is 3,963 miles, while the polar radius is 3,950 miles. The equatorial radius is 13 miles longer than the polar radius because the Earth gradually bulges out towards the Equator. Earth's mass is 6.6 sextillion tons (5.9722 x 1024 kilograms). Its distance from the sun is referred to as 1 astronomical unit (AU), which is equivalent to 149,597,870,700 meters. Physical Properties and Geology of the Interior: The Earth has three main layers in its interior: the inner core, the outer core, and the mantle. The mantle is the thickest layer of the Earth and is made up of molten metal that is in a state of constant motion and convection. It is thought that the mantle’s convection process directs the circulation of plate tectonics and the temperature of the mantle is comparable to the surface of the sun. The outer core is a low viscosity fluid that has very violent convection currents. This layer is also responsible for the Earth’s magnetosphere. The inner core is slowly growing as the outer core cools down and forms onto the inner core. The inner core is extremely dense and solid and spins quickly. While the magnetosphere is formed due to the outer core, the inner core also plays a role in it. Page 12

EARTH Earth’s crust: The Earth’s crust is the thinnest layer of the Earth and provides for the habitual Other Names: Terra, Gaea environment that all living things can survive on. There are two types of crust: oceanic and continental. Oceanic crust is found at the bottom of oceans and Source: (https://www.nasa.gov/topics/earth/index.html. 2020). sometimes below continental crust. It is typically deeper and denser than continental crust. The crust is split into tectonic plates that float on top of the mantle. Mission – CHAMP: NASA conducted a study called Challenging Mini-Satellite Payload (CHAMP). The mission launched July 15, 2000 and was completed on September 19, 2010. During its mission, Challenging Mini-satellite Payload (CHAMP) generated simultaneously highly precise gravity and magnetic field measurements for the first time. These measurements have allowed scientists to detect the spatial variations of both fields as well as their variability with time. CHAMP data has applications in global climate studies, oceanography, weather forecasting, disaster research, navigation, geophysics, geodesy, and solar terrestrial physics. Sources: http://www.desy.de/gna/interpedia/greek_myth/creation.html. 2020. https://www.space.com/17638-how-big-is-earth.html. 2017. https://www.space.com/17081-how-far-is-earth-from-the-sun.html. 2017. https://www.zmescience.com/other/science-abc/layers-earth-structure/. 2018. https://www.sciencedaily.com/terms/earth's_atmosphere.htm. 2020. Page 13

MERCURY Myth: “The cult of Mercury is ancient, and tradition has it that his temple on the Other Names: The Swift Planet Aventine Hill in Rome was dedicated in 495 BCE. There Mercury was associated with Maia, who became identified as his mother through her Source: (https://www.businessinsider.com/mercury-rare-transit-across-sun-how-to-watch-2019- association with the Greek Maia, one of the Pleiades, who was the mother of 11. 2019). Hermes by Zeus; likewise, because of that Greek connection, Mercury was considered the son of Jupiter. Both Mercury and Maia were honored in the Mercuralia festival on May 15, the dedication day of Mercury’s temple on the Aventine.” Size of Mercury, Mass, and Distance from the Sun: Mercury has a radius of 1,516 miles, which is about 1/3 of the size of Earth’s. The mass of Mercury is 330x10^23 kg, which is about 0.055 times the size of Earth’s mass. Its distance from the sun is 0.4 astronomical units (AU), which is equivalent to 36 million miles. Physical Properties and Geology of the Interior: After Earth, Mercury is the second densest planet. It has a large metallic core, which consumes 85% of the planet’s radius. While scientists are not very sure still, evidence suggests that this core may be partly molten or liquid. The outer shell of the planet is much smaller and is only approximately 250 miles thick. While it is very small, it is also comparable to Earth’s mantle and crust. Page 14

MERCURY Mercury’s Atmosphere: Mercury’s atmosphere is very thin. Due to the thin atmosphere, it doesn’t have any Other Names: The Swift Planet moons. There is a thin exosphere made up of atoms that came from the planet’s surface and lifted up by the solar wind or by meteoroid strikes. Mercury's exosphere is Source: (https://nssdc.gsfc.nasa.gov/imgcat/html/object_page/m10_aom_20.html. 2015). composed of oxygen, sodium, hydrogen, helium and potassium. The planet’s magnetosphere interacts with solar wind to create intense magnetic tornadoes that funnel the fast, hot solar wind plasma down to the surface of the planet. When the ions strike the surface, they knock off neutrally charged atoms and send them into the atmosphere. Mission - BepiColombo: The European Space Agency (ESA) is conducting the BepiColombo mission to Mercury. The mission involves two components: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The spacecraft will have a nearly 7 year interplanetary cruise. On arrival in 2025, the spacecraft will be captured into polar orbit, which will be lowered using chemical thrusters and will last one Earth year with a possible one year extension. The objectives of the mission are to study Mercury's form, interior structure, geology, composition, and craters, origin, structure, and dynamics of its magnetic field, composition and dynamics of the vestigial atmosphere, test Einstein's theory of general relativity, search for asteroids sunward of Earth, and to generally study the origin and evolution of a planet close to a parent star. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://www.space.com/18647-how-big-is-mercury.html. 2016. https://www.britannica.com/topic/Cupid. 2020. Page 15

VENUS Myth: Venus had two main divine lovers: her husband Vulcan (Hephaistos) Other Names: The Morning Star and Mars (Ares). There is a myth concerning Venus' and Mars' love affair and how Vulcan cunningly trapped them in bed with a net. Therefore, Vulcan and Source: (https://www.space.com/44-venus-second-planet-from-the-sun-brightest-planet- Venus had a loveless marriage and no children. Albeit, the goddess of love and in-solar-system.html. 2020). sex was not barren; she had many children from different gods. With Mars, she gave birth to Timor (Phobos) the personification of fear who accompanied his father into battle, his twin Metus (Deimos) the personification of terror, Concordia (Harmonia) the goddess of harmony and concord, and the Cupids (Erotes) who were a collection of winged love deities who represented the different aspects of love. Size of Venus, Mass, and Distance from the Sun: Venus has a mass of 4.867 × 10^24 kg. It is very close in size to Earth and its diameter is only a few miles shorter. The radius of Venus is 3,760 miles. It is located on average 67 million miles away from the sun. Physical Properties and Geology of the Interior: While scientists are still studying and not completely sure, they believe that Venus has an interior similar to Earth’s. They believe it has a somewhat liquid core and a rocky mantle. The lack of a magnetic field leads scientists to ponder about the core of this planet. They believe that the core likely doesn’t spin fast enough, although it could mean that the core is completely solid, unlike Earth’s. The surface of Venus is almost entirely volcanic with an entire surface covered in cooled lava. Page 16

VENUS Venus’ Atmosphere: Venus’ atmosphere is made up almost completely of carbon dioxide with small amounts Other Names: The Morning Star of nitrogen and sulfuric acid. This composition causes a runaway greenhouse effect that makes the planet extremely hot. It is the hottest planet in the solar system because of Source: (https://www.space.com/38311-akatsuki.html. 2017). this. When the rocky core of Venus formed, it captured much of the gas gravitationally. The planet has heavy clouds that shield it, preventing visible observations of the surface and protecting it from bombardment by all but the largest meteorites. The pressure of the atmosphere of Venus is also very intense and about 90 times heavier than Earth’s. Mission – Akatsuki: The Akatsuki mission is led by the Japanese Space Agency (JAXA) and was designed to study the dynamics of the atmosphere of Venus from orbit, particularly the upper atmosphere super-rotation and the three-dimensional motion in the lower part of the atmosphere, using multi-wavelength imaging. It will also measure atmospheric temperatures and look for evidence of volcanic activity and lightning. The spacecraft launched on May 20, 2010 but a faulty fuel pressure valve resulted in the spacecraft not being able to enter Venus’ atmosphere. After five years, they were able to successfully enter the planet’s atmosphere and record data. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d, 2020. https://www.ancient.eu/venus/. 2013. https://www.space.com/18529-distance-to-venus.html. 2012. https://www.space.com/18530-how-big-is-venus.html. 2012. https://www.space.com/18527-venus-atmosphere.html. 2018. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2010-020D. 2020. Page 17

MARS Myth: Mars was the Roman god of war and second only to Jupiter in the Roman pantheon. Other Names: Red Planet Although most of the myths involving the god were borrowed from the Greek god of war Ares, Mars, nevertheless, had some features which were uniquely Roman. Source: (https://www.seis-insight.eu/en/public-2/martian-science/internal-models- Considered more level-headed than the often impulsive and disruptive Ares, Mars of-mars. 2019). was also seen as a more virtuous figure by the more martial-oriented Romans. As a protector of Rome and the Roman way of life and as a defender of city borders and frontiers, important festivals connected to warfare were held in his honor and the god was also closely associated with the wolf and woodpecker. Size of Mars, Mass, and Distance from the Sun: Mar’s mass is 6.42 x 10^23 kilograms, which is about 10 times less than Earth’s mass. Mar’s diameter is 4,222 miles and it is located 135.68 million miles away from the sun. Physical Properties and Geology of the Interior: Mars’ core is likely has a solid core composed of iron, nickel and sulfur and it does not move. These two facts result in the planet’s lack of a magnetic field. Without a global magnetic field, radiation bombards the planet making it relatively inhospitable compared to Earth. While there have been no volcanic eruptions for millions of years, the mantle that lies beneath the crust is largely dormant. It is made up primarily of silicon, oxygen, iron, and magnesium and probably has the consistency of soft rocky paste. The crust consists mostly of volcanic basalt rock with a layer of fine dust on top. The soil of Mars also holds nutrients such as sodium, potassium, chloride and magnesium. Page 18

MARS Mars’ Atmosphere: The atmosphere of Mars is very thin and is about 95 percent carbon dioxide. Due to the Other Names: Red Planet thin atmosphere, Mars is too cold for liquid water to exist, but features on the surface suggest that water once flowed on Mars. Today, water exists in the form of ice in the Source: (https://www.nasa.gov/perseverance/overview. 2020). soil, and in sheets of ice in the polar ice caps. The temperature on Mars ranges from 70 degrees Fahrenheit to about minus 225 degrees Fahrenheit. Mission – Mars Perseverance: The Mars Perseverance Rover is expected to launch in the summer of 2020. The Mars Perseverance mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars. The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. The mission also provides opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars. These include testing a method for producing oxygen from the Martian atmosphere, identifying other resources (such as subsurface water), improving landing techniques, and characterizing weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://www.ancient.eu/Mars/. 2014. https://www.space.com/16871-how-big-is-mars.html. 2012. https://www.space.com/16895-what-is-mars-made-of.html. 2017. https://www.nasa.gov/perseverance/overview. 2020. Page 19

JUPITER Myth and Name Origin: Jupiter was named after the king of the Roman gods. Among the many gods of the Other Names: Giant Planet Romans, Jupiter, the son of Saturn, was the supreme god, associated with thunder, lightning, and storms. The first citizens of what would become Rome believed they Source: (https://www.space.com/18385-jupiter-atmosphere.html. 2018). were watched over by the spirits of their ancestors, and they added a triad of gods to these spirits. He was Jupiter Elicius - one who brings forth. By the rise of the Republic, Jupiter’s identity as the greatest of all the gods was firmly established. Jupiter's most important title was Jupiter Optimus Maximus, meaning the Best and Greatest and signifying his role as father of the gods. Size of Jupiter, Mass, and Distance from the Sun: Jupiter is the largest planet in the solar system. Its mass is 1.898 x 10^27 kilograms and it has a radius of 43,440.7 miles. Its surface area is so large that it is 120 times the size of Earth. It is also 482.41 million miles away from the sun. Physical Properties and Atmosphere: Jupiter is very similar to a tiny star. It is composed predominantly of hydrogen and helium, but lacks the mass and density to become a star. Since the planet is all gas, there is no surface. Scientists determine the surface of the planet at the point that its atmospheric pressure is the same as Earth. Inside of Jupiter is only layers of gas until you reach the core. It is believed that Jupiter has a dense core surrounded by a layer of metallic hydrogen. Scientists are still unsure whether the core is liquid or a solid rock. There is also some evidence that suggests the core is melting away or could become nonexistent. Jupiter’s atmosphere consists of 90% hydrogen and 10% helium. The temperatures and pressure of the atmosphere divide the gases into several layers. Page 20

JUPITER Jupiter’s Moons: Scientists believe that Jupiter has 79 moons. One of its most fascinating moons is Other Names: Giant Planet Europa. Europa has a thick icy shell, which scientists are now convinced, is covering a large ocean that is a lot bigger than the oceans on Earth. It has an equatorial diameter of Source: (https://solarsystem.nasa.gov/moons/jupiter-moons/europa/in-depth/. 2019). 1,940 miles, which is just slightly smaller than our moon’s. Europa orbits Jupiter every 3.5 days and is locked by gravity to Jupiter, so the same hemisphere of the moon always faces the planet. Mission – Europa Clipper Mission: Now that scientists are fairly certain that there is water present on this moon (and a whole lot of it) they are anxious and eager to send a mission to this planet in search of life. NASA is currently working on the Europa Clipper Mission which has an estimated launch readiness date of 2025. The spacecraft will make 45 passes over Europa, shifting its flight path for each flyby to soar over a different location so that it eventually scans nearly the entire moon. After each flyby, the spacecraft will send its haul of data back to Earth. The time between flybys will also give scientists time to study the data and consider adjusting the timing and trajectory of future flybys if they find regions that spark curiosity and need more study. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://www.ancient.eu/jupiter/. 2014. http://coolcosmos.ipac.caltech.edu/ask/97-How-did-Jupiter-get-its-name-. 2020. https://www.space.com/18392-how-big-is-jupiter.html. 2018. https://www.space.com/18388-what-is-jupiter-made-of.html. 2012. https://solarsystem.nasa.gov/moons/jupiter-moons/europa/in-depth/. 2019. Page 21

SATURN Myth and Name Origin: Saturn was named after the Roman god of agriculture. Saturn (Saturnus) was Other Names: Ringed Planet a Roman god with a similar history to Cronus from Greek mythology. Often depicted in art wielding a scythe he was considered an agricultural god, especially Source: (https://solarsystem.nasa.gov/resources/17631/saturn-interior-cutaway-illustration. associated with seed-corn. The Saturnalia festival, named after him, was one of the 2017). most important and lively events in the Roman calendar and the god also had a major temple dedicated to him in the Roman Forum of Rome. Size of Saturn, Mass, and Distance from the Sun: Saturn is the second largest planet in the solar system, behind Jupiter. Its mass is 5.68 x 1026 kilograms and it has a radius of 36,184 miles. It is also 929.86 million miles away from the sun. Physical Properties, Atmosphere, and Rings: Saturn is predominantly composed of hydrogen and helium with traces of ices containing ammonia, methane, and water. Because Saturn lacks a traditional ground, scientists consider the surface of the planet to begin when the pressure exceeds one bar, the approximate pressure at sea level on Earth. The layers of the atmosphere continue through the interior of the planet. As you go further into the planet, the gases in the planet become metallic due to the intense pressure. This process allows the planet to have a magnetic field. The core of the planet is composed of rocky materials, but scientists have yet to conclude whether the core is a liquid or solid. Saturn’s most predominant feature is its stunning rings, which stretch as far out as 262,670 miles. The rings are made up of ice and rock pieces that create a rainbow effect as they refract the light from the sun. Page 22

SATURN Saturn’s Moons: Saturn has 82 moons that range in size from larger than mercury to as small as a sports Other Names: Ringed Planet arena. The planet’s largest moon, Titan, has Earth-like qualities of water like rivers, lakes, Source: (https://www.nasa.gov/press-release/nasas-dragonfly-will-fly-around-titan- looking-for-origins-signs-of-life. 2019). and seas. It also the only moon we know about that has a substantial atmosphere that is contained primarily of nitrogen. Titan has clouds, rain, rivers, lakes and seas of liquid hydrocarbons like methane and ethane. Beneath Titan’s thick crust of water ice is more liquid that has the potential to support life. Mission – Dragonfly Mission: NASA is currently working on a mission to Saturn’s famous moon, Titan. Dragonfly will launch in 2026 and arrive in 2034 and will fly to many promising locations looking for prebiotic chemical processes that are common on both Titan and Earth. The instruments will search for chemical evidence of past or extant life in the moon’s sand dunes, impact creators, and water systems. Dragonfly will visit a world filled with a wide variety of organic compounds, which are the building blocks of life and could teach us about the origin of life itself.” says Thomas Zurbuchen, NASA Associate Administrator. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://www.ancient.eu/Saturn/. 2015. http://coolcosmos.ipac.caltech.edu/ask/115-How-did-Saturn-get-its-name-. 2020. https://www.space.com/18479-how-big-is-saturn.html. 2012. https://www.space.com/18472-what-is-saturn-made-of.html. 2012. 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. 2020. https://www.nasa.gov/press-release/nasas-dragonfly-will-fly-around-titan-looking-for- origins-signs-of-life. 2019. Page 23

URANUS Myth and Name Origin: Uranus was named after the Greek god of the sky. Uranus was Father Sky, the Other Names: Ice Giant Ancient Greek personification of the heavens and, for a while, the ruler of the known universe. Fatherless, he was conceived by Gaea alone, with whom he formed Source: (https://www.bbc.com/future/article/20140822-the-mission-to-an-un-loved-planet. the primordial couple, thus becoming an ancestor of almost all Greek gods. 2014). However, he was a cruel husband, and he didn’t allow any of his children to leave the womb of their mother, which eventually led to a rebellion and his demise at the hands of his son, Cronus. Size of Uranus, Mass, and Distance from the Sun: Uranus has a mass of 86 septillion kilograms, which is 14.5 times as bigger than Earth. Uranus has a radius of 15,792 miles, which is 4 times bigger than Earth’s. Its density is 1.27 grams per cubic centimeter, which makes it the second least densest planet in the solar system. This helps scientists indicate that the planet is predominantly ice and not gas. It is also 1.8409 billion miles away from the sun. Physical Properties and Atmosphere: Uranus has an alluring blue-green atmosphere that helped scientists learn about its components, as well as the planet’s. As Uranus is a gas giant, it doesn’t have a ground surface and it is comprised of many layers of different types of gas and ice. Uranus contains only a small portion of hydrogen and helium, which is very different than the other gas giants. It is predominantly made up of different types of ice: mainly water, but also methane and ammonia. While most planets have rocky molten cores, the center of Uranus is thought to contain icy materials. The liquid core makes up 80 percent of the mass of the planet, mostly comprised of water, methane, and ammonia ice, though it only extends to about 20 percent of the radius. Page 24

URANUS Uranus’ Moons: Uranus’ moons are unique, as they all received their names from Shakespeare’s writings Other Names: Ice Giant rather than mythology. One of the more complex moons that Uranus has is Ariel, which is thought to consist mostly of roughly equal amounts of water ice and silicate rock. Source: (https://voyager.jpl.nasa.gov/mission/science/uranus/. 2020). Carbon dioxide has also been detected on Ariel. The surface of this moon is very new compared to the other moons of Uranus and it holds more recent geological impacts. Scientists now believe that the surface is porous, casting reflectivity-decreasing shadows when illuminated at other angles. Mission – Voyager 2: NASA’s Voyager 2 flew past Uranus at a very close distance in 1986, revealing many discoveries about the planet. The Voyager 2 launched in 1977 and flew past the planets, eventually making its way out of our solar system and into interstellar space. While passing Uranus, it revealed complex surfaces on 5 of its moons, indicative of varying geologic pasts. It also detected 11 previously unseen moons and two previously unseen rings. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://www.greekmythology.com/Other_Gods/Uranus/uranus.html. 2020. http://coolcosmos.ipac.caltech.edu/ask/136-How-did-Uranus-get-its-name-. 2020. https://www.space.com/18710-how-big-is-uranus.html. 2018. https://www.space.com/18706-uranus-composition.html. 2018. https://solarsystem.nasa.gov/moons/uranus- moons/overview/?page=0&per_page=40&order=name+asc&search=&placeholder=Ent er+moon+name&condition_1=69%3Aparent_id&condition_2=moon%3Abody_type%3 Ailike. 2020. Page 25

NEPTUNE Myth and Name Origin: Neptune was named after the Roman god of the sea. Neptune had a reputation for Other Names: Big Blue Planet having a violent temper and lustful nature. Ocean storms and earthquakes were a reflection of his demeanor. Considering his difficult beginnings, it’s no wonder that Source: (https://www.wired.com/story/neptune-is-a-windy-chilly-and-baffling-planet-lets-go/. Neptune had a temperamental personality. Saturn ate him whole along with his 2019). siblings, to avoid the possibility of any of the offspring seizing his ruling status, although eventually this plot was ineffective. Saturn was killed by Jupiter and the sons did achieve ruler status, at which time Neptune took over the sea. Size of Neptune, Mass, and Distance from the Sun: Neptune has a mass of 1.02 x 1026kilograms, which is 17 times as bigger than Earth. While it is the fourth largest planet in diameter, it is the third largest in mass due to the gas it holds. Neptune has a radius of 15,299 miles. It is also 2.7818 billion miles away from the sun. Physical Properties, Atmosphere, and Rings: Neptune’s first layer is an icy atmosphere, which is mostly composed of hydrogen and helium. There is also evidence that points to a presence of methane, as well. Neptune has the strongest winds in the solar system, with speeds up to 1,300 miles per hour. Since Neptune is a gas giant, it does not have a ground surface and consists of layers of gas, ice, and a rocky core. The core is made up of iron and other metals and has a mass that it is slightly larger than Earth. The mantle of the planet is made up of a water-ammonia ocean with temperatures ranging from 3,140 degrees Fahrenheit to 8,540 Fahrenheit. Neptune also has a series of rings. Its rings contain prominent arcs, likely due to the influence of one of Neptune's moons. They are made up of ice particles and silicates making the rings reddish. Page 26

NEPTUNE Neptune’s Moons: Neptune has 14 moons and the first discovered moon was found just 17 days after the Other Names: Big Blue Planet planet was initially discovered in the 1800’s. Triton is the largest of Neptune’s moons and is unusual because it is the only large moon in our solar system that orbits in the Source: (https://solarsystem.nasa.gov/moons/neptune-moons/triton/in-depth/. 2020). opposite direction of its planet's rotation―a retrograde orbit. Scientists believe that it originated as a Kuiper Belt object and got trapped in Neptune’s orbit. It also shares many similarities with Pluto, which also originated as a Kuiper Belt object. Mission – Voyager 2: NASA’s Voyager 2 flew past Neptune at a very close distance in the summer of 1986, revealing many discoveries about the planet. The Voyager 2 launched in 1977 and flew past the planets, eventually making its way out of our solar system and into interstellar space. It passed about 3,000 miles above the planet’s north pole, making this its closest encounter to a planet by that point. The Voyager 2 spent 12 years travelling before it reached Neptune and was able to spend a few months observing and studying it from June to October, sending many pictures and data to scientists on Earth to study. Sources: https://www.reference.com/science/nicknames-planets-64501a5f46cb723d. 2020. https://mythology.net/roman/roman-gods/neptune/. 2017. http://coolcosmos.ipac.caltech.edu/ask/139-How-did-Neptune-get-its-name-. 2020. https://www.space.com/18924-how-big-is-neptune.html. 2012. https://www.space.com/18920-neptune-composition.html. 2012. https://solarsystem.nasa.gov/moons/neptune- moons/overview/?page=0&per_page=40&order=name+asc&search=&placeholder=Ent er+moon+name&condition_1=90%3Aparent_id&condition_2=moon%3Abody_type%3 Ailike. 2020. Page 27

PLUTO Myth of Pluto: The god Pluto lived in a palace in the underworld, far away from the other gods who A Dwarf Planet lived at Mount Olympus. It was his role to claim the souls that inhabited his underworld domain. Those who entered were destined to stay there for eternity. The Source: (https://www.iau.org/static/resolutions/Resolution_GA26-5-6.pdf. 2015) entrance gates were guarded by his enormous three-headed dog, Cerberus. Pluto is the God of the underworld and presides over the afterlife. Size of Pluto, Mass, and Distance from the Sun: Pluto has a mass of 1.31 x 1022 kilograms, which is 2-tenths of a percent of Earth’s mass. It has a diameter of 1,473 miles, about 2/3 the size of Earth’s moon. Pluto is 3,670,050,000 miles away from the sun and is located after Neptune in the Kuiper Belt. Physical Properties: Pluto has a solid surface of nitrogen ice with methane and carbon. The surface of the planet holds mountains that could actually be volcanoes. There are also many designs in the ice that help scientists determine the composition of the surface, as well as the whole planet. Scientists believe that the interior of the planet is very active. During Pluto’s early formation period, the core failed to gain enough material to have a stronger gravitational pull, which is what makes it now a dwarf planet. The core is expected to be rocky, while the mantle is thought to have recently been a liquid water ocean, but is now mainly frozen. Page 28

PLUTO Pluto’s Atmosphere: Scientists thought that Pluto wouldn’t have an atmosphere because of its tiny size, but A Dwarf Planet they were surprised to learn that it did. It has a brilliant blue glow that is predominantly nitrogen-based. The atmosphere also consists of several layers and extends about 100 Source: (https://www.space.com/18564-pluto-atmosphere.html. 2016). miles above the surface of the planet. From the atmosphere, scientists were also able to see that Pluto’s weather changes on a daily basis, just as Earth’s does. Mission – New Horizons: NASA launched their New Horizons mission in 2006. The spacecraft finally reached Pluto in 2015 and was the first spacecraft to flyby the planet and its moons. The 9 year journey allowed scientists to test many maneuvers built into the spacecraft. One of the most intriguing of these happened during its flyby past Jupiter. It used a gravity assist maneuver that increased its velocity by about 9,000 miles per hour, shortening its trip to Pluto by 3 years. The New Horizons spacecraft helped scientists obtain answers to many of their questions, including the basic question of how big Pluto is. Sources: https://mythology.net/roman/roman-gods/pluto/. 2017. https://www.space.com/18564-pluto-atmosphere.html. 2016. https://solarsystem.nasa.gov/missions/new-horizons/in-depth/. 2019. https://www.iau.org/static/resolutions/Resolution_GA26-5-6.pdf. 2015. https://www.space.com/18562-what-is-pluto-made-of.html. 2016. https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/in-depth/. 2020. https://spaceplace.nasa.gov/ice-dwarf/en/. 2019. Page 29

ERIS Myth of Eris: Eris played an important role in the events that eventually led to the Trojan War. All A Dwarf Planet of the Olympians had been invited to the wedding of Peleus and Thetis, who would become the parents of Achilles; however, Eris was not invited, due to her inclination Source: (https://solarstory.net/planets/eris. 2016) to cause discord. As a means of revenge, Eris dropped the golden Apple of Discord into the party, which resulted in war between Hera, Athena, and Aphrodite. Resources https://www.greekmythology.com/Other_Gods/Eris/eris.html. 2020. Size of Eris, Mass, and Distance from the Sun: https://solarsystem.nasa.gov/planets/dwarf-planets/eris/in-depth/. 2019. Eris has a mass of 1.66 × 10^22 kilograms, which is similar to Pluto’s. It has a https://www.theverge.com/2016/7/1/11686404/nasa-new-horizons- radius of 722 miles, which is about 1/5 of Earth’s. Eris is about 68 AU away from mission-funding-extension-mu69. 2016. the sun and is located in the Kuiper Belt like Pluto is. Physical Properties, Atmosphere, and Moon: As Eris orbits around the sun, its atmosphere varies. While it is closer to the sun, it has an active atmosphere, however, it quickly freezes when it moves further away from the sun and the frozen particles then fall to the dwarf planet’s surface. Scientists believe that Eris has an icy and rocky surface similar to Pluto’s, but they have yet to determine what the interior composition of the dwarf planet is, according to NASA in 2019. It is currently known to have one moon named Dysnomia. Mission – New Horizons: The New Horizons Mission that flew by Pluto in 2015 received further funding from NASA to fly deeper into the Kuiper Belt and fly by Eris and about two dozen other objects located in the belt. Scientists are excited to receive this data, as they’ll be able to observe Eris from a new angle that is unseen from Earth and can hopefully learn more about its composition. Page 30

HAUMEA Myth of Haumea: Haumea is a goddess in Hawaii mythology. She was the Goddess who created the A Dwarf Planet islands of Hawaii and the fire within the volcanoes on the islands is Haumea. In her Fire Goddess form she is called Pele. She is also called by a number of different names, Source: (https://solarsystem.nasa.gov/planets/dwarf-planets/haumea/in-depth/. 2019) including Lailai and Papa, showing that she can take on many different guises, morphing from old woman to young girl and becoming her own daughter or Resources granddaughter. Haumea was thought of as ancestral Mother, divine creatrix and the spirit of Mother Nature that flows through everything and everyone. https://goddess-pages.co.uk/galive/issue-29-home/the-re- emergence-of-haumea/. 2020. Size of Haumea, Mass, and Distance from the Sun: https://solarsystem.nasa.gov/planets/dwarf-planets/haumea/in- Eris has a mass of 4.01 × 10^21 kg. It has a radius of 385 miles, which is about 1/14 of depth/. 2019. Earth’s. Eris is about 43 AU away from the sun and is located in the Kuiper Belt like Pluto is. Physical Properties, Atmosphere, and Moon: Haumea completes one rotation every four hours, which makes it one of the fastest moving objects known in the solar system. This transneptunian object is thought to be made entirely of rock with an icy outer shell. However, scientists don’t know enough about it yet and are not sure what the interior is comprised of. It is currently unknown whether or not Haumea has an atmosphere. It does have two known moons, though, Namaka and Hi’aka, and is the first dwarf planet known to have rings. Missions and Discovery: There currently aren’t any missions planned for Haumea, however, scientists have been able to learn a significant amount about this dwarf planet so far from Earth. The planet was discovered in 2004 and its moons were discovered in 2005. It was officially recognized as a dwarf planet by the IAU in 2008 when it was officially given its name. Page 31

MAKEMAKE Myth of Haumea: Makemake was named from Polynesian mythology. According to their myths, A Dwarf Planet Makemake was born from a floating skull that was washed from a temple into the sea. He created the first humans. Together with his companion, the goddess Haua, he Source: (https://solarsystem.nasa.gov/planets/dwarf-planets/makemake/in-depth/. 2019) brought flocks of migratory seabirds to the island. He was the god of fertility and the chief god of the \"Tangata manu\" or bird-man cult. He was worshipped in the form of Resources sea birds, which were considered his incarnation. https://astrology.richardbrown.com/NewPlanets/Makemake-mythology.shtml. 2020. Size of Makemake, Mass, and Distance from the Sun: https://solarsystem.nasa.gov/planets/dwarf-planets/makemake/in-depth/. Eris has a mass of 2.5 × 10^21 kilograms. It has a radius of 444 miles, which is 2019. about 1/9 of Earth’s. Eris is about 45.8 AU away from the sun and is located in the Kuiper Belt like Pluto is. Physical Properties, Atmosphere, and Moon: Makemake makes one rotation every 22.5 hours, which is similar to Earth’s, although it takes over 300 years to revolve around the sun. While little is still known about Makemake, scientists believe that it may form a thin atmosphere while it is near the sun, similar to dwarf planet Eris. Its surface appears to be similar to Pluto’s with a reddish-brown color that indicates there is frozen pellets of ethane and methane on the surface. It is currently known to have one moon which was nicknamed MK2. Missions and Discovery: There currently aren’t any missions planned for Haumea, however, scientists have been able to learn a significant amount about this dwarf planet so far from Earth. The planet was discovered in 2005 and its moon was more recently discovered in 2016. It was officially recognized as a dwarf planet by the IAU in 2008 when it was officially given its name. Page 32

CERES Myth of Ceres: This dwarf planet was named after a goddess in Roman mythology, Ceres. Ceres is a A Dwarf Planet goddess of the common people; she doesn’t just govern over agriculture, but also Source: (https://solarsystem.nasa.gov/planets/dwarf-planets/ceres/overview/. 2019) over fertility in general. Much of what Ceres is responsible for concerns the daily Resources lives of ordinary people, such as getting married and having children. https://mythology.net/roman/roman-gods/ceres/. 2016. https://solarsystem.nasa.gov/planets/dwarf-planets/ceres/in-depth/. Size of Ceres, Mass, and Distance from the Sun: 2019. https://www.nasa.gov/mission_pages/dawn/main/index.html. 2020. Eris has a mass of 8.958 × 10^20 kilograms. It has a radius of 296 miles, which is about 1/13 of Earth’s. Eris is about 2.8 AU away from the sun and is located in the asteroid belt between Mars and Jupiter, unlike the rest of the dwarf planets. Physical Properties and Atmosphere: Ceres has a rotation of 9 hours and a revolution of 4.6 Earth years. Ceres is described as an embryonic planet, meaning it began its formation but never completed it due to Jupiter’s strong gravitational pull. Ceres has a similar structure to the terrestrial planets but is much less dense due to a suspected icy interior. It does have a layered interior but the layers are not as well defined. The core is thought to be solid rock while the mantle is believed to be water ice. Ceres has a thin atmosphere that likely contains water vapor. Ceres is one of few other places in the solar system that has the potential for life due to the presence of water. Mission – Dawn: The Dawn mission was the first mission to go to a dwarf planet and orbit around it. It launched in 2007 and went into orbit around Ceres in 2015. Dawn made many accomplishments, including showing how important location was to the way objects in the early solar system formed and evolved. It also reinforced the idea that dwarf planets could have hosted oceans over a significant part of their history, and potentially still do. Page 33

HALLEY’S COMET Mythology about comets: During the times of ancient mythology, a comet seen in the sky brought fear. They have Source: (https://www.universetoday.com/101234/was-the-repeating-passage-of-halleys- been branded as \"the Harbinger of Doom\" and \"the Menace of the Universe” and have comet-known-of-in-ancient-times./ 2013). been regarded as both omens of disaster and messengers of the gods. Their erratic and unpredictable movements led people in many cultures to believe that the gods dictated Resources their motions and were sending them as a message. What were the gods trying to say? http://deepimpact.umd.edu/science/comets-cultures.html. 2017. Some cultures read the message by the images that they saw upon looking at the comet. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/1p- halley/in-depth/. 2019. Size of Halley’s Comet, Mass, and Distance from the Sun: https://www.universetoday.com/40692/what-are-comets-made-of/. Halley’s Comet has a mass of 2.2×1014 kg. It has a mean diameter of 11 km and its 2009. dimensions are 15km x 8km. At aphelion in 1948, Halley was 35.25 AU from the sun. https://nssdc.gsfc.nasa.gov/planetary/giotto.html. 2015. Physical Composition Comets begin as loose collections of ice, dust and small rocky particles and as it approaches the inner solar system, solar radiation causes the materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them. The streams of dust and gas form an atmosphere around the comet called the coma, and the force exerted on the coma by the radiation pressure of the Sun and solar wind cause a tail to form. The tail always points away from the sun. Mission – Giotto The Giotto Mission launched in July 1985 to study Halley’s Comet. It’s objectives were to obtain photographs of the nucleus, determine the composition of the coma, characterize the processes that occur in the atmosphere and ionosphere, determine the composition of dust particles, measure the total gas-production rate, and, investigate the systems of plasma flows resulting from the cometary-solar wind interaction. Page 34

PALLAS Myth: Pallas was a Titan god in Greek mythology, son of the Titans Crius and Eurybia. He An Asteroid had two brothers, Astraeus and Perses, and he was married to Styx, with whom he had a number of children: Zelus, Nike, Kratos, Bia, Scylla, Fontes, and Lacus. He Source: (http://www.astronoo.com/en/pallas.html. 2020). was the Titan of warcraft. During the Titanomachy, Pallas was killed by the goddess Athena. Resources https://www.britannica.com/topic/Athena-Greek-mythology. 2020. Size of Pallas, Mass, and Distance from the Sun: https://www.greekmythology.com/Titans/Pallas/pallas.html. 2020. Pallas has a mass of 205,000 kg. Its dimensions are 582km x 556km x 500km. It is https://www.space.com/14749-asteroids-composition.html. 2012. 2.77 AU away from the sun. https://www.space.com/16105-asteroid-belt.html. 2017. https://www.space.com/nasa-considering-athena-mission-asteroid- Physical Composition and Belt: pallas.html. 2019. Asteroids are essentially space rocks that vary greatly in size. They can also contain metals and other elements, including water. Their density varies greatly as some can be similar to loose piles of ruble, while others are very compact. Millions of asteroids are located in the asteroid belt between Mars and Jupiter. It is thought that these asteroids were in the midst of the solar system during its early formation stage and got caught in Jupiter’s orbit so they never formed onto another planet. Mission – Athena Scientists are considering a mission to study the Pallas asteroid. The mission is named Athena and would have a launch date of 2022. NASA’s Dawn mission concluded last fall after observing the Ceres and Vesta asteroids in the asteroid belt, but now scientists hope to obtain funding to launch Athena to study Pallas. The mission isn’t expected to discover as much as the Dawn mission, but they believe it will be a good stepping stone to learn more about the unique chemistry they believe Pallas has. Page 35