Chapter 8 Moons Rings and Plutoids https www

Chapter 8 Moons, Rings, and Plutoids https: //www. youtube. com/watch ? v=PTE 08 q. Zz 7 MM nice Cassini images You should be asking about Dwarf Planets as well. Copyright © 2010 Pearson Education, Inc.

Lunar eclipse https: //www. vox. com/science-andhealth/2018/1/23/16911140/total-lunar-eclipse-2018 blue-moon-supermoon-blood-explained Copyright © 2010 Pearson Education, Inc.

Once in a blue moon (Jan 31) A blue moon can refer to either the third full moon in a season with four full moons, or the second full moon in a month. [1] Most years have twelve full moons that occur approximately monthly. In addition to those twelve full lunar cycles, each solar calendar year contains roughly eleven days more. The extra days accumulate, so every two or three years there is an extra full moon. The term "blue moon" comes from folklore. Different traditions and conventions place the extra "blue" full moon at different times in the year. In calculating the dates for Lent and Easter, the Clergy identify the Lent Moon. It is thought that historically when the moon's timing was too early, they named an earlier moon as a "betrayer moon" (belewe moon), thus the Lent moon came at its expected time. [2] Copyright © 2010 Pearson Education, Inc.

The “systems” of our solar system • • • Sun Terrestrial planets Jovian planets The Jovian moons The asteroid and Kuyper belts – Kuyper belt objects = Plutoids • A whole bunch more – Gas, dust, ions, magnetic fields, Oort Cloud Copyright © 2010 Pearson Education, Inc.

Small solar systems with much happening • Jupiter and Saturn are so big • With so many moons • And with a few big (Mercury sized) moons • Some with liquid water, more than Earth • Some with volcanic activity, more than Earth Copyright © 2010 Pearson Education, Inc.

Units of Chapter 8 The Galilean Moons of Jupiter The Large Moons of Saturn and Neptune The Medium-Sized Jovian Moons Planetary Rings Beyond Neptune Plutoids and the Kuiper Belt Summary of Chapter 8 Copyright © 2010 Pearson Education, Inc.

What are the various white dots? Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc.

Learning goals for chapter 8 1. Understand the general properties of Galilean moons, the only other moons we can see with binocs. 2. Discuss composition and origin of the Titan’s atmosphere. 3. Explain the evidence for Triton to be captured by Neptune 4. Understand the new Cassini data on Enceladus 5. Describe structure and origin of Saturn’s rings 6. Explain the Kuyper belt relative to the origin of the solar system Copyright © 2010 Pearson Education, Inc.

Projects groups of 2 or 3 1. List the known moons for each of the planets. 1. Skip Earth’s moon 2. Then choose one of the larger moons, and write 1. the major properties 1. Size, distance from planet, period of orbit (moonth) 2. Who discovered it Copyright © 2010 Pearson Education, Inc.

The list is too big to know them all • http: //www. windows 2 universe. org/our_solar_system/moons_table. html Copyright © 2010 Pearson Education, Inc.

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8. 1 The Galilean Moons of Jupiter All four Jovian planets have extensive moon systems, and more are continually being discovered. Why? The Galilean moons of Jupiter are those observed by Galileo G in 16 th c: Io, Europa, Ganymede, and Callisto. Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter This image shows Jupiter with two of its Galilean moons. Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter The Galilean moons and their orbits Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Their interiors Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Io is the densest of Jupiter’s moons, and the most geologically active object in the solar system. • It has many active volcanoes, some quite large. • Io can change surface features in a few weeks. • Io has no craters; they fill in too fast – Io has the youngest surface of any solar system object. Copyright © 2010 Pearson Education, Inc.

Why is Io so geologically active? • • It’s close to a huge planet. Gravity is huge. Tidal forces are huge, 100 m lift! So why doesn’t it get tidally locked? – Europa, nearby, tugs it every pass, few days Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Io is very close to Jupiter, and also experiences gravitational forces from Europa. The tidal forces are huge, and provide the energy for the volcanoes. Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Europa has no craters; surface is water ice, possibly with liquid water below. Tidal forces stress and crack ice; water flows, keeping surface relatively flat. Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Ganymede is the largest moon in the solar system – larger than Pluto and Mercury. It has a history similar to Earth’s Moon, but with water ice instead of lunar rock. Copyright © 2010 Pearson Education, Inc.

8. 1 The Galilean Moons of Jupiter Callisto is similar to Ganymede; no evidence of plate activity. Copyright © 2010 Pearson Education, Inc.

Jan 26: 8. 2 The Large Moons of Saturn and Neptune Titan has been known for many years to have an atmosphere thicker and denser than Earth’s; mostly nitrogen and argon. Makes surface impossible to see; the picture at right was taken from only 4000 km away. Copyright © 2010 Pearson Education, Inc.

Titan’s interior • Look at figure 8. 13. • What is unusual about Titan’s interior? • How can silicates (rock) sink to the core when usually iron does? • Where did Titan’s iron core go? • How was Titan formed? Copyright © 2010 Pearson Education, Inc.

8. 2 The Large Moons of Saturn and Neptune Infrared image of Titan, showing detail, and possible icy volcano Few craters, consistent with active surface Complex chemical interactions in atmosphere Copyright © 2010 Pearson Education, Inc.

8. 2 The Large Moons of Saturn and Neptune The Huygens lander took these images of the surface of Titan. Copyright © 2010 Pearson Education, Inc.

8. 2 The Large Moons of Saturn and Neptune Trace chemicals in Titan’s atmosphere make it chemically complex. Copyright © 2010 Pearson Education, Inc.

8. 3 The Medium-Sized Jovian Moons Densities of these moons suggest that they are rock and water ice. Copyright © 2010 Pearson Education, Inc.

30 jan: 8. 3 The Medium-Sized Jovian Moons of Saturn, in natural color Note the similarities, as well as the large crater on Mimas. Copyright © 2010 Pearson Education, Inc.

Multiple plume jets erupting from the four tiger-stripe fractures near Enceladus’s south pole are visible in this Cassini image. The jets appear not only on the edge of Enceladus’s disk but also where they rise up into sunlight from sources on the night side of the moon Copyright © 2010 Pearson Education, Inc.

Enceladus makes its own ring Copyright © 2010 Pearson Education, Inc.

My favorite Jovian moon: Enceladus • http: //dx. doi. org/10. 1063/PT. 3. 1331 • Finding liquid water is a fundamental quest of planetary science. • Because H 2 O is the simplest stable compound of the first and third most cosmically abundant elements, it is one of the commonest molecules in the universe. • Our solar system is no exception: During its formation, temperatures in the protosolar nebula were low enough that water ice could condense in most places beyond what is now the asteroid belt. • The solid worlds of the outer solar system thus tend to be rich in water ice, and the moons of the giant planets typically comprise roughly equal parts rock and ice. Copyright © 2010 Pearson Education, Inc.

• From our parochial point of view as biological entities, however, H 2 O is most interesting in its liquid form, which is essential for the maintenance of life on Earth. • If life exists elsewhere, the best places to look for it are those with liquid water. Compared with ice and water vapor, liquid water is stable over a narrow range of temperature and pressure. So it is relatively rare in the solar system. • But Jupiter’s large moon Europa has been a center of attention for planetary scientists since the late 1990 s, when the Galileo orbiter discovered evidence for a global water ocean beneath Europa’s icy surface. • More recently, the Cassini orbiter has revealed a place that not only probably hosts liquid water but also is obligingly launching fresh samples of that water into space for analysis by spacecraft instruments. That place is Enceladus—a moon of Saturn 500 km in diameter. Copyright © 2010 Pearson Education, Inc.

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Enceladus facts • Dead center E ring of saturn • E ring is mostly water ice and is constantly replenished • Heat at tiger stripes • Geysers of water ice from stripes • Constant snowfall, young craters, high albedo • Cassini is the major probe to find chemical information • Theory is tidal heating centered at south pole • Ongoing geological activity according to Daniel’s book • Possibility of life in liquid water with salts Copyright © 2010 Pearson Education, Inc.

The current model for how Enceladus makes water guysers What body creates the tidal tug ? Copyright © 2010 Pearson Education, Inc.

8. 3 The Medium-Sized Jovian Moons of Uranus and Neptune Copyright © 2010 Pearson Education, Inc.

8. 3 The Medium-Sized Jovian Moons Miranda shows evidence of a violent past, although the origin of the surface features is unknown. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings The ring system of Saturn is large and complex, and easily seen from Earth. The other Jovian planets have ring systems as well. https: //www. youtube. com/watch? v=Ay. FMP d. HU 1 n 0 start Copyright © 2010 Pearson Education, Inc. at 6: 00 min to 10: 15

8. 4 Planetary Rings The rings are not solid; they are composed of small rocky and icy particles. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Our view of Saturn’s rings changes as the planets move in their orbits. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Why are there rings? Copyright © 2010 Pearson Education, Inc. The Roche limit is where the tidal forces of the planet are too strong for a moon (held together by gravity) to survive; this is where rings are formed.

8. 4 Roche Limit All observed ring systems are within this limit. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Voyager probes showed Saturn’s rings to be much more complex than originally thought. Earth is shown on the same scale as the rings. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings “Shepherd” moons define the edges of some of the rings. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Jupiter has been found to have a small, thin ring. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings The rings of Uranus are more complex. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Two shepherd moons keep the epsilon ring from diffusing. Copyright © 2010 Pearson Education, Inc.

8. 4 Planetary Rings Neptune has five rings, three narrow and two wide. Copyright © 2010 Pearson Education, Inc.

This Exoplanet’s Ring System Puts Saturn to Shame • Chapter_08, moons, rings, plutoidsThis Exoplanet. docx Copyright © 2010 Pearson Education, Inc.

Why don’t terrestrial planets have rings? 1. Roche Limit is very low 2. Not enough ices around to form the rings 3. Rings are short lived and jovian planets are grabbing all the stuff that wanders into the solar system. Copyright © 2010 Pearson Education, Inc.

Quiz: ring formation • Explain how rings form around a planet – Include a description of tidal forces – Include a description of the Roche Limit – Include a description of shepherd moons Copyright © 2010 Pearson Education, Inc.

The formation process for moons and rings • Draw a picture • Notice how these are the same 3 mechanisms, either inside or outside the Roche Limit • How are moons made? – Accretion, like the planets – Capture of a wandering body – Impact with the planet and capture • How are rings made? – Capture of dust and debris from early SS – Debris from moon-asteroid or planet-asteroid or moon-planet impact – Debris from moon that wandered into the roche limit. • The origin of Saturn’s rings. 1: 49 Copyright © 2010 Pearson Education, Inc.

8. 5 Beyond Neptune Pluto was discovered in 1930. It was thought to be needed to explain irregularities in the orbits of Uranus and Neptune, but it turned out that there were no such irregularities. Copyright © 2010 Pearson Education, Inc.

8. 5 Beyond Neptune Pluto’s moon, Charon, was discovered in 1978. It is orbitally locked to Pluto, and about a sixth as large. Pluto also has two smaller moons, Nix and Hydra, discovered in 2005. Copyright © 2010 Pearson Education, Inc.

What a difference a space probe makes in our learning! http: //apod. nasa. gov/apod/ap 15 0918. html https: //twitter. com/NASANew. Ho rizons? ref_src=twsrc%5 Egoogle %7 Ctwcamp%5 Eserp%7 Ctwgr %5 Eauthor Copyright © 2010 Pearson Education, Inc.

8. 5 Beyond Neptune Charon’s orbit is at a large angle to the plane of Pluto’s orbit. Copyright © 2010 Pearson Education, Inc.

8. 6 Plutoids and the Kuiper Belt The first Kuiper belt objects were observed in the 1990 s, and more than 700 are now known. Some of them are comparable in size to Pluto. These images show Eris and its moon Dysnomia. Copyright © 2010 Pearson Education, Inc.

8. 6 Plutoids and the Kuiper Belt This figure shows several of the largest known trans-Neptunian objects, now collectively called plutoids. Copyright © 2010 Pearson Education, Inc.

Where do dwarf planets fit in? • Is a dwarf planet the same as a plutoid? • P 237 Copyright © 2010 Pearson Education, Inc.

The ninth planet? • http: //www. nytimes. com/2016/01/21/science/space/ninth-planet-solar-system-beyondpluto. html? rref=collection%2 Fsectioncollection%2 Fscience&action=click&content. Collection=science&region =rank&module=package&version=highlights&content. Placement=1&pgtype=sectionfront&_r=1 Copyright © 2010 Pearson Education, Inc.

Summary of Chapter 8 • Outer solar system has 6 large moons, 12 medium ones, and many smaller ones. • Titan has a thick atmosphere and may have flowing rivers of methane. • Triton has a fractured surface and a retrograde orbit. • Medium-sized moons of Saturn and Uranus are mostly rock and water ice. • Saturn’s rings are complex, and some are defined by shepherd moons. Copyright © 2010 Pearson Education, Inc.

Summary of Chapter 8, cont. • The Roche limit is the closest a moon can survive near a planet; inside this limit rings form instead. • Jupiter, Uranus, and Neptune all have faint ring systems. • Pluto has three moons, Charon, Nix, and Hydra. • Dwarf planets beyond Neptune (including Pluto) are now known as plutoids. Copyright © 2010 Pearson Education, Inc.

Supporting views • Look at videos on support files for review Copyright © 2010 Pearson Education, Inc.

Final check/quiz • Solar walk movie on size comparison, without subtitles Copyright © 2010 Pearson Education, Inc.

More video • Rings of the Jovian Planets 43 min, 360 p, History Channel overexaggeration Copyright © 2010 Pearson Education, Inc.

What if the planets were as close as our moon…. • https: //www. youtube. com/watch? v=us. Y C_Z 36 r. Hw Copyright © 2010 Pearson Education, Inc.

Recent Titan pictures • In Dec 2012, http: //www. esa. int/Our_Activities/Space_Science/Cassini_spots_mini_Nile_River_on_Saturn_moon shows rivers and seas of methane and ethane • In 2005, Huygens gave surface pictures before it froze. http: //www. esa. int/Our_Activities/Space_Science/Cassini- Huygens/New_images_from_Titan Copyright © 2010 Pearson Education, Inc.

quiz • On a new page, sketch and describe three ways that a moon can be made. • On the flip side, sketch and describe three ways that rings can be formed around a planet. Define the Roche limit, and describe why it exists. Copyright © 2010 Pearson Education, Inc.

Review for the term or yearend final 1. If it’s on the periodic, it will probably be on the final. 2. If it’s key point in the slides but didn’t fit on the periodic, it will probably be on the final. 1. So, in class, spend a few minutes finding these topics. 3. If I have said “I really like this topic” it will probably be on the final. Copyright © 2010 Pearson Education, Inc.