7.1: PLANETARY SYSTEMS FORM AROUND A STAR Nebular hypothesis - rotating cloud collapses under its own gravity. flattens out into a disk and forms starWe also discuss several other topics like csusci
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at the center. planets form around it from debris in the disk general characteristics of the solar system that support the nebular hypothesis: everything orbits in roughly the same plane - ecliptic, except outer objects, which orbit at different planes bc they are farther away. 7.2: THE SOLAR SYSTEM BEGAN WITH A DISK angular momentum (L) - the rotational momentum of a spinning object. “mass that’s moving.” the larger momentum, the harder it is to stop. angular momentum depends on the mass of the rotating body (m), rotational velocity (v) and the distance from the rotation axis (r) (how spread out is the mass? example: figure skater spreads her arms out to slow herself down). L = mvr angular momentum is “conserved” - when r (rotation axis changes), v (rotational velocity) changes to conserve the angular momentum. Figure skaters conserve their angular momentum by bringing their arms in or out to change their velocity (assuming their mass stays the same). to change the angular momentum of a rotating object, the object would have to flatten out. protostar changes its angular momentum via jets by shooting out most of its material (otherwise it would explode on itself). The rest of the 1% of material becomes planets or stays in the disk- aka us, Earth. giant molecular clouds are in constant rotation due to collisions with each other. Starts to rotate faster as it begins to collapse. As cloud gets flatter,, it spins faster and gravitates toward the center (like a chef spinning a pizza dough, it becomes flatter as it spins faster). Cloud becomes an accretion disk and forms a protostar. Accretion disk - material falls toward the star, rotates around it. Anything around the star eventually becomes a planet or becomes ejected via protostellar jets Grains of dust become planets - electrically charged dust gently collide and survive other collisions. Eventually they build up into rocks, boulders, planetoids, and finally protoplanets, as they clear out their path of debris and other planetesimals. Sometimes, they don’t survive collisions relative to their size, so they have to start over again protostar - forms at the center of an accretion disk after the cloud has collapsed on itself planetesimal - large enough to have their own gravitational pull. attract materials from the outside, withstand harder collisions. Asteroids, comets, objects in Kuiper belt. Sometimes they collide with each other and become protoplanets. Millions of years ago, there were hundreds in our star system protoplanet - clears out its path of debris and planetesimals. majority of the original interstellar cloud’s angular momentum ends up ejected into space 7.3: INNER DISK AND OUTER DISK FORMED AT DIFFERENT TEMPERATURES potential energy - the energy relative to other factors. A ball sitting on a table has potential energy because it has potential!! But it has not been acted on to produce energy. kinetic energy - the energy of something while it is in motion. The ball is thrown and becomes kinetic energy because it’s moving (: if you drop an object, you turn potential energy into kinetic energy total energy is “conserved” - energy can not be created or destroyed, total energy remains constant inner disk is hot because it is closer to the protostar. Material has also been falling from a greater distance and as it has passed through, it has gained momentum. Faster rotation also causes collisions which create more heat. outer disk is cold because it is farther from the protostar, material hasn’t fallen very far, and it rotates slower since it’s farther inner disk materials - refractory stuff- does not melt as easily, rocks and metalsouter disk materials - volatiles- melt/evaporate easily such as water, methane, CO2, ammonia frost line - distance from the star where temperature is low enough for volatiles to condense into solids. Cold af. Any planet that forms in front of the frost line will be made of refractory terrestrial materials (Venus, Earth, Mars, Mercury). Anything behind frost line is cold and icey or gassy (Jupiter, Saturn, Uranus, Neptune). atmospheres are formed in terrestrial planets from accretion, volcanic eruptions, & impacts from other comets, ect. primary atmosphere - Planets gather gasses from the disk by core accretion-gas capture, form their own mini accretion disks secondary atmosphere - planets with low mass can’t hold onto their primary atmospheres and later emit gasses from their interiors (volcanoes) 7.4: THE FORMATION OF OUR SOLAR SYSTEM High mass planets maintain their primary atmospheres. They have more gravity which allows the atmospheres to be kept despite solar winds. Low mass planets have secondary atmospheres. Solar Winds blew away the primary atmosphere. Gasses emitted from the planets interiors, forming secondary gases. 7.5: PLANETARY SYSTEMS ARE COMMON Two most popular methods of exoplanet detection: Spectroscopic radial velocity: A star exhibits a Doppler shift during the planets orbital period. Transit: Photometry detects small changes in a stars light levels. They detect very small changes in the light emitted by the star. About all of the stars in our galaxy should have at least one planet. Habitable zone - zone around a star where liquid water could exist on a planet. The hotter the star the further the habitable zone is from the star. The cooler the closer. Super earth - Terrestrial planets in the habitable zone that are much larger than earth. Our earth experienced a collision with another planet during formation, so our solar system doesn’t have one. Planetary migration - planet slowly moves inward towards the sun. Jupiter most likely migrated inward and threw some super earths out of the inner orbit by tugging on their orbits. Saturn was likely the reason Jupiter was brought back out. 9.1: ATMOSPHERES OF TERRESTRIAL PLANETS / ATMOSPHERES CHANGE OVER TIME Mercury and the Moon don’t have atmospheres because they are much smaller so they don’t have as much internal heat and less volcanism. Less mass and magnetic field Venus, Earth, Mars’ secondary atmosphere formation - gases in protoplanet’s disk are mostly H and He, and are captured by the young planetesimals - accretion. As sunlight heated up atmosphere, primary atmosphere escaped. Released gas from volcanoes & impacts from comets/asteroids adds H2O and other necessary molecules to form secondary atmospheres volatiles captured during accretion ended up in atmospheres when they were collected from comets, solar system, ect. They were later released through volcanoes and end up in atmosphere volatiles in terrestrial atmospheres come from outer solar system. atmospheres are formed in terrestrial planets from accretion, volcanic eruptions, & impacts from comets/ asteroids 9.2: SECONDARY ATMOSPHERES EVOLVE surface gravity - is the gravitational pull at a planet’s surface (venus and earth has stronger surface gravities, mars has lower) it’s measured by mass of the planet, radius surface gravity determines a planet’s atmosphere. More surface gravity = thicker atmospheregreenhouse effect - energy from sun arrives in the form of visible light, infrared light becomes trapped and heats interior. An equilibrium temperature balances 2 rates of energy so that the planet’s temp doesn’t overheat. If we didn’t have an atmosphere, the infrared would be radiated into space and we’d be a cold ass planet ): greenhouse gases - nitrogen, oxygen, water make up most of Earth’s greenhouse gases. Rest of 1% is argon, CO2, neon, Helium, and methane proportion and total amount (due to size of planet) is important in order to have good greenhouse effect. Venus has weak greenhouse effect because it is smaller greenhouse effect raises a planet’s equilibrium temperature because the planet can withstand higher temps As the Sun grew older, it became brighter. Venus was warmed as it exited the habitable zone and released CO2, leading to runaway greenhouse effect. H2O evaporated Which of the following is part of the Earth’s natural greenhouse effect? Earth’s surface and atmospheric gases absorb energy and then give off infrared light. 9.4: COMPARING TERRESTRIAL ATMOSPHERES Venus and Mars have same proportion of CO2 in their atmospheres differ from Earth’s CO2 (Earth has slightly more) majority of Earth’s CO2 is in limestone, in the surface Venus is hot because it is so close to the sun Mars is cold because it doesn’t have enough CO2 to produce greenhouse effect abundance of greenhouse gases in the atmosphere absorbs UV light percentage of an atmosphere’s greenhouse gas content factor into the greenhouse effect, but have little to no effect if the total amount is not enough to achieve significant greenhouse effect main greenhouse gas(es) of: Venus - CO2 (96.5%) Nitrogen (3.5%) Earth - CO2 (98%) Nitrogen, Oxygen, other (2%) Mars - CO2 (96%) Nitrogen, Oxygen, other (4%) Venus’ water evaporated to the top of its atmosphere and was broken down by UV radiation from the sun. Hydrogen escaped into space and O atoms formed ozone O3 oxygen (O2) is in Earth’s atmosphere, but not in Mars. Earth is farther from sun, so lower temp equilibrium. Life evolved and removed CO2, adding more O2. CO2 buried in Earth’s surface On Mars, O2 settled out of atmosphere and oxidized on surface ozone - Sun’s UV breaks O2 into individual O atoms. Those atoms recombine to form O3, ozone. Ozone absorbs UV until it loses one O and becomes O2. Starts process over again! (: and we are protected from harmful radiation. Mars has no O, so it can’t make O3, so UV blasts the surface. Heat distributed poorly on Mars because of low pressure Earth’s magnetosphere - 10x Earth’s radius, 1000x volume. Magnetic field blocks solar wind particles, and because they are charged, they do not easily cross magnetic field lines when charged particles get trapped in our magnetosphere, it forms aurorae Venus and Mars don’t have a magnetosphere because of little or no atmosphere Earth absorbs UV most 9.5: CLIMATES CHANGE difference between global climate and weather. Global climate - general median temperature of a region, area or planet. Weather refers to the immediate temperature of a particular region. Ex: the climate of Texas is hot. The weather is dry, 98 degrees today factors that can cause climate change on a planet - planet’s tilt (minor tilt, mild seasons. Major tilt, extreme seasons), sun’s brightness or other astronomical activity, geological activity such as volcanoes or extreme weather, human activity three main types of geenhouse gases on Earth - CO2, methane, ozone they are increasing because of factories, cars, production of animals for human consumption rise in global temperatures is due to human activity because temps have never been this high.. we can prove it by looking at other factors that would otherwise contribute. The sun is currently not very hot, so it’s not the sun’s fault. CO2 level has never been higher than 300 ppm and now it is at 400ppm and growing exponentially consequences of global warming - avg global temp goes up. forest fires, natural disasters, rising sea level due to melting ice caps, animal extinction. Basically, we all gone die if we don’t fix this right meow 10.1: WORLDS OF GAS & LIQUID: THE GIANT PLANETS Giant planets are large, cold, and massive Giant planets, compared to terrestrials - further from the sun, less energy, greater mass, larger radii, higher surface gravities, no surfaces, short rotation periods. Giants receive much less energy because of their great distance from the sun. Gas giants: Larger radii, Mostly H, He, low H2O, volatiles, Closer to the sun, small cores. Ice Giants: Smaller radii, Less H, He. Higher H2O, further from the sun, larger cores. Gas giants are composed of light and volatile elements. H and He are abundant in giants. The frost giants contain a larger percentage of heavy elements whereas Gas giants have trace amounts. Jupiter has no seasons due to little obliquity. Saturn and Neptune have seasons due to a normal obliquity. Uranus has extreme seasons due to its 97.8-degree obliquity. 10.2: WEATHER OF THE GIANTS Colors in Jupiter’s clouds indicate - Hydrogen is extremely abundant and is involved in much of its chemistry, which affects the colors. Great Red Spot - is a large cyclone and the largest storm in the solar system. It is powered by the constant alternating climate on Jupiter’s surface The colors on saturn’s cloud tops are much less pronounced than Jupiter’s, indicating less complex chemistry occurring. relationship between the ice giants’ chemical composition and their color - They are made up of Methane and Ammonia ice crystals as well as high amounts of H2O. wind speeds affect bands and zones - Produces strong Coriolis effect, causing storm rotation the deflection of north/south moving winds due to planet’s rotation Saturn’s and Neptune’s equatorial winds are strongest maximum speeds up to 2,000 km/hr. 10.3: INTERIORS OF THE GIANTS The interiors of the giants are hot and dense internal heat of the giants is caused by the speed of the planets rotation. internal heat from the planets result in their extreme weather because thermal energy drives strong convection. Material from the convection is deflected into the strong Coriolis effect on the rapidly rotating planets. 10.5: PLANETARY MIGRATION super-earth - Radii between Earth and Neptune, most common planet size. Planetary migration - outer planets like Jupiter interact with inner planets and get pulled inward. May have altered the inner solar system into what is is today Jupiter got out of the inner solar system and back to where it is today because Saturn pulled it back out towards the outer solar system. 11.1: MOONS AND RINGS Most of the planets in our solar system have moons, except for Mercury and Venus orbital classifications of Moons: Irregular: orbit at random inclinations, far from the planet, high eccentricity orbits, retrograde obits, few are tidally locked, didn’t form with their planet. Regular: Orbit in the equatorial plane, close to the planet, nearly circular orbits, same direction as the planets rotation, tidally locked, relatively large mass, formed with the planet. Planets that are close to the sun are composed of rock while the further ones contain ice. Elliptical orbits such as Io’s are affected by tidal heating. As Io approaches, tidal forces increase and when it recedes tidal forces decrease. The constant change applies mechanical heating to the interior. 11.2 GEOLOGICAL CLASSIFICATIONS OF MOONS geologically active - Moons with active geological features such as volcanoes. once-active - Moons that once had these features but are now dormant or have ceased. never active - Moons that never had these features. Tidal heating is the cause of Io’s volcanoes. Tidal heating constantly heats the interior of the moon. Elliptical orbits change direction of tidal forces constantly. The cause of Europa’s warm interior, and its underground ocean is from tidal heating from Jupiter. Io, Europa, and Enceladus (Saturn) are said to have “young” surfaces because the surfaces are constantly remade through internal heating pushing material to the surface filling in craters. Ganymede (Jupiter), Mimas (Saturn), and Miranda (Uranus) are thought to have been “once active” geologically because their surfaces show signs of geological activity and their orbits suggest previous tidal heating. Callisto (Jupiter) has a very “old” surface and “never geologically active” because there was never any significant tidal heating. Io is covered in sulfur from volcanoes but Europa is covered in water ice because Io is closer to the planet and is made of rock whereas Europa is much further and contains a layer of ice. It is very likely Europa has an ocean of liquid water beneath it’s surface because its tidal heating would likely melt the Icy surface. cryovolcanism - a volcano erupts volatiles such as water or methane. Titan’s (Saturn) atmosphere is mostly made of methane (CH4), and why it’s able to undergo a CH4 hydrologic cycle - Methane remains liquid despite the extremely low temperatures of the moon. Active geology replenishes the atmospheres CH4 levels. 11.3: RING SYSTEMS Jupiter, Saturn, Uranus and Neptune have rings Rings are made of water ice, swarms of tiny moons. They orbit their planets because they are too close to break away, but too close to collide. ring systems form when material such as rocks orbit inside the planets roche limit. The Roche limit is the boundary that allows moons to form. If material is inside the Roche limit, a moon will not form. 11.4: RING SYSTEMS CAN HAVE COMPLEX STRUCTURE Saturn’s rings are made up of water ice for the most part. Most likely an ice moon torn apart by tidal forces. Diffuse rings are contain less material and are less dense whereas regular rings contain a dense amount of material. shepherd moons - shape the rings by guiding the particles with their gravity forcing them to stay in their orbit. solar system bodies that can have rings - planets, moons and even asteroids. 12.1: DWARF PLANETS AND SMALL SOLAR SYSTEM BODIES dwarf planet - planetesimals left over from the formation of the solar system. Includes asteroids, comets, meteors, ect. differs from a “classical planet” (ex: Mercury, Neptune) because it has not cleared out its orbit of other stuff; there are still other large objects in its orbit Kuiper Belt - extends from Neptune’s orbit (30 AU) to approximately 50 AU Home to small icy bodies, some dwarf planets, trans neptunian objects (objects that intersect Neptune’s orbit) dwarf planets’ orbits are much more inclined than classical planets Ceres, Pluto, Haumea, Makemake, and Eris 12.2: ASTEROIDS ARE PIECES OF THE PAST The Asteroid Belt - between Mars and Jupiter very unlikely to run into one by accident because they are so far apart Near-Earth asteroids come close to Earth. Amors group is outside Mars’ orbit Apollo group crosses Mars & Earth orbits Atens stays inside Mars’ orbit, crosses Earth’s orbit Asteroid types S - stony, similar to igneous rocks M - stone, iron, and nickel C - have a lot of carbon and volatiles like H2O, most common, mostly in outer asteroid belt 12.3: COMETS ARE CLUMPS OF ICE Oort cloud - one light year away from our planets. Contains mostly comets orbiting very slowly around our sun. If the sun were the shape of a basketball in Smith Hall, the Oort cloud would cover most of Maryland. We are so tiny! short period comets originated in the Kuiper belt, Neptune and other giants scatter them inward toward the sun. Orbits are somewhat elongated, not circular like most orbits. Orbital periods of few years to few centuries long period comets - orbits come really close to the sun and really far from the sun. Extremely elongated orbits. Orbital period from 200years to 1,000,000yrs Good luck everyone! (: Merry Christmas!!QUIZ 5 When light from a hot, dense object passes through a cloud of cool gas before it is passed through a prism or diffraction grating, an absorption spectrum is produced The unit of measurement of the wavelength of electromagnetic waves are Which the following forms of electromagnetic radiation is listed from highest to lowest energy levels? x-ray, ultraviolet, infrared, radio When light from a hot, dense object is passed through a prism or diffraction grating, a continuous spectrum is produced. The energy required to transition a photon from n=3 to n=5 in a hydrogen atom is less than the energy required to transition from n=5 to n=2 The energy required to transition a photon from n=3.7 to n=5 in a hydrogen atom is _____ the energy required to transition from n=5 to n=2. The answer is impossible because a photon cannot be on n=3.7, it has to be on either 3 or 4. In order for an electron in a hydrogen atom to increase its energy level from n=2 to n=3, it must absorb a photon with a wavelength of 6560 Å. electromagnetic radiation is listed from longest to shortest wavelength: long radio, infrared, yellow, ultraviolet An atom is ionized when it absorbs a photon of very short wavelength, causing the electron to leave the atom entirely. If an electromagnetic wave’s frequency is increased, then its energy is increased, its wavelength is decreased, and its color is changed from “redder” to “bluer” QUIZ 6 Star A is four times the distance from Earth as Star B, but both stars have exactly the same brightness in the sky. because Star A is 16 times more luminous than Star B. Ranking of the speed of the stars from moving fastest toward Earth to moving fastest away from Earth. E - 6470 Å, A - 6490 Å, B - 6600 Å, D - 6580 Å, C - 6560 Å Consider the Planck curves of two stars of the same size. Star A has a peak wavelength of 3800 Å (ultraviolet) and Star B has a peak wavelength of 8000 Å (infrared). Star B appears red in color to the eye.Suppose Star A and B are the same size and are the same distance from Earth. Star A’s surface temperature is twice that of Star B. Star B’s luminosity is 1/16 of Star A. Consider the Planck curves of two stars of the same size. Star A has a peak wavelength of 3800 Å (ultraviolet) and Star B has a peak wavelength of 8000 Å (infrared). Star A emits more red light. Consider two stars with the same surface temperature. Star A is twice the radius of star B. Star A’s luminosity is four times that of Star B. Consider the Planck curves of two stars of the same size. Star A has a peak wavelength of 3800 Å (ultraviolet) and Star B has a peak wavelength of 8000 Å (infrared). Which star has the greatest redshift? Cannot be determined from the information given. You take the spectra of two stars moving toward Earth. Star A’s absorption lines are blueshifted by 24 Å and Star B’s aborption lines are blueshifted by 17 Å. Star A is moving faster. You meausre the intensity of a star in all wavelengths from gamma-ray through radio and notice that its peak intensity occurs in the infrared. The surface temperature of this star is approximately 3000 K. You take the spectra of a star moving toward Earth, and recognize one of its hydrogen absorption lines from your laboratory experiment. In your lab experiment, you calculated the wavelength of this line as 6560 Å. The wavelength of this same line in the star is 6551 Å. QUIZ 7 1. You have an 8-inch (203.2 mm) Schmidt-Cassegrain telecope with a focal length of 2032 mm (80 in). You own three eyepieces with focal lengths of 40 mm, 70 mm, and 80 mm. Which eyepiece will yield the highest magnification with which to observe individual crater details on the Moon? The 40mm eyepiece 2. Which telescope would be ideal for wide-field sky surveys? A 1 m telescope with a 2 m focal length. 3. Despite their large apertures, radio telescopes get relatively low resolution because: radio wavelengths are long. 4. Why do astronomers build telescopes on mountains? To minimize the effects of the atmosphere. 5. Which of the following optical telescope attachments are not used in modern astronomical research? Eyepiece 6. The smallest angle a telescope can ultimately distinguish objects from each other at large distances is itsdiffraction limit 7. Pick the incorrect answer: Why build telescopes on the ground when we can launch them into space? Ground-based telescopes get much higher resolution. 8. Images of bright stars often reveal “spikes” that are caused by diffraction around the secondary mirror support truss. 9. Which of the following is a type of telescope? Refractor, Cassegrain Reflector, Radio telescope 10. The Hubble Space Telescope has a 2.4 m primary mirror with an effective focal length of 57.6 m. What sort of observations is this telescope ideally suited for? Objects that subtend a relatively narrow field of view at high resolution. QUIZ 8 1. Which of the following stars is closest to us? Sirius (parallax angle = 0.38”) 2. Suppose a star were measured with a parallax of 0.25”. Its distance is 4 parsec. 3. What is the distance to a star (in parsecs) that has a parallax angle of 0.1 arcseconds 10 4. The measurement of a star’s brightness as seen from Earth is called ____________, written as apparent magnitude, m 5. Absolute magnitude is the magnitude a star would have as seen from 10 parsecs. 6. Vega has an apparent magnitude of 0.03 and an absolute magnitude of 0.58. If it were moved twice as far from Earth as it is now, which of the following would occur? apparent magnitude number would increase 7. On Earth, the parallax angle measured for the star Procyon is 0.29 arcseconds. If you were to measure Procyon’s parallax angle from Venus, what would the parallax angle be? (Note: Earth’s orbital radius is larger than Venus’s orbital radius.) less than 0.29 arcseconds 8. Star X is 10 parsecs away, and Star Y is 50 parsecs away. What is the parallax angle for Star X? 1/10 an arcsecond 9. Consider two stars (X and Y). If Star X is 3 parsecs away and Star Y is 5 parsecs away, which has the greater parallax angle? Star X 10. Star G has an apparent magnitude of 5.0 and an absolute magnitude of 4.0. Star H has an apparent magnitude of 4.0 and an absolute magnitude of 5.0. Which of the following statements is true about viewing these two stars from Earth? H will appear brighter than G.QUIZ 9 1. Why is a G3II star more luminous than a G3V star? The G3II star is larger than the G3V star. 2. Which of the following can be used as a proxy for Luminosity? Absolute Magnitude 3. Which of the following binary systems is most likely to be an eclipsing binary? System C with an orbital inclination of 90° 4. What characteristics of a star’s spectra determines its luminosity class? The strength of its spectral lines. 5. A star’s mass determines all of the following characteristics except the following: Radial Velocity 6. Which spectral classification represents the largest star? K3II 7. The vast majority of stars are Main Sequence 8. All of the following are types of binary star systems except: Parallax Binaries 9. Consider a binary star system where Star A is twice the mass of the Star B and an orbital inclination of 90°. Which statement about this system is incorrect? The orbital period of the system varies with the eccentricity of their orbits. 10. The Hertzsprung-Russell diagram can plot stars according to the following combination of values except: Radius vs. Luminosity 11. What percentage of stars belong to binary systems? 30-50%QUIZ 11 - THE FORMATION OF PLANETARY SYSTEMS (CH 7) 1. Place the following events in the correct order 1. Interstellar cloud collapses due to gravity 2. A rotating disk forms 3. Dust grains stick together by static electricity 4. Small bodies collide to form larger bodies 5. Primary atmospheres form 6. Primary atmospheres are lost 7. Secondary atmospheres form 3. The following planets still have their primary atmospheres: Uranus and Saturn 4. All of the planets, moons, comets, and asteroids in orbit around the Sun account for approximately .1% of the total mass of our solar system 5. As material falls onto the accretion disk, its kinetic energy is converted into thermal energy 6. Planets form in the accretion disk. 7. Terrestrial planets are composed of mostly refractory materials. 8. Gas giants giants can grow their primary atmospheres because: There is a high abundance of refractory and volatile materials in the outer disk 9. The terrestrial planets and the giant planets have different compositions because: the terrestrial planets are closer to the Sun. 10. Since angular momentum is conserved, an ice skater will rotate faster if she pulls her arms inward. 11. A protostar forms at the center of a circumstellar disk QUIZ 12 - THE ATMOSPHERES OF TERRESTRIAL PLANETS (CH 9) 1. False: Venus, Earth, & Mars retained their primary atmospheres, while Mercury and the Moon lost theirs. 2. Mercury and the Moon do not have atmospheres because: Both lack magnetic fields, Their small size prevents them from retaining heat that could otherwise drive volcanism, Atmospheric gases at Mercury are heated to high thermal motion from the Sun such that they achieve escape velocity, The Moon’s low mass means that it has a very low escape velocity, allowing atmospheric gases to easily escape. 3. Unlike Venus and Earth, Mars lost most of its secondary atmosphere because: it couldn’t trap as much heat due to its relatively small size, it lacks a magnetic field, it doesn’t have as strong a gravitational pull due to its relatively small mass. 4. Despite their atmospheres being primarily composed of carbon dioxide, Mars is much colder than Venus because Venus is closer to the Sun and Mars doesn’t have as much carbon dioxide in its atmosphere as does Venus. 5. True: If Mars were moved to the same distance from the Sun as Venus, it would still be colder than Venus. 6. False: If Earth were moved to the same distance from the Sun as Venus, it would still be cooler than Venus. 7. Why does Mars have a much weaker greenhouse effect than Venus and Earth? It has more total CO2 in its atmosphere than Venus 8. Earth and Venus have similar masses, radii, and densities. Why, despite their physical similarities, did Venus undergo a runaway greenhouse effect? Venus has a much slower rotational period (243 days), allowing one hemisphere to experience extremely long “days” of heating. Venus lacks a strong magnetic field to protect it from the Solar wind and CME outbursts from the Sun. Venus formed closer to the Sun. As the Sun brightened over time, it warmed Venus faster than it warmed Earth. Venus experienced extreme volcanism as it warmed, releasing almost all of its stored CO2 into its atmosphere. 9. Why are the oxygen levels in Mars’ atmosphere practically nonexistant? Without life, oxygen was never replenished in the atmosphere so it settled to and oxidized the surface. 10. Rank in order from most effective to less effective to not at all effective the causes of accelerated global warming in the last 50 years 1.Burning of fossil fuels, namely oil and coal 2.Growth, concentration, and slaughter of livestock 3.Volcanic activity 4.Solar activity QUIZ 13 - THE GIANT PLANETS (CH 10) 1. Which planet has the most extreme seasons of any in the Solar System? Uranus (obliquity 98°) 2. How do we know giant planets have strong magnetic fields? They all experience aurorae at their poles. 3. The cloud bands of the giant planets are arranged in alternating east-west and west-east zones. What causes these winds? Their short rotation periods.4. The giant planets, particularly Jupiter and Saturn, are oblate in their shape because of their rapid rotation. 5. If Jupiter and Saturn are both made of mostly hydrogen and helium, why is Jupiter appear so colorful and Saturn so bland? Saturn has different chemical reactions in its atmosphere than Jupiter. 6. Despite their relative lack of sunlight, the giant planets experience powerful and sometimes very long-lasting storms. This is due to their internal heat. 7. Jupiter’s striking colors are indicative of complex chemistry in its atmosphere. 8. Which kind of planet contains a higher percentage of metallic hydrogen in their interiors? Gas giants 9. Which kind of planet contains a high percentage of water and volatiles in their interiors? Ice giants 10. Why were astronomers surprised to detect the fastest sustained winds in the solar system on Neptune? Because at 30 AU, Neptune gets the least amount of sunlight of the major planets. QUIZ 14 - MOONS & RINGS (CH 11) 1. The Roche limit is the minimum distance to which a large moon can approach a planet without being torn apart by tidal forces. 2. What is the most likely explanation for the origin of regular moons? They formed in an accretion disk with their host planet. 3. Even though Io is covered in active volcanoes and Europa is covered in ice, in what way are these two moons similar? Both formed in the same accretion disk with Jupiter. Both are geolocially active. Their interiors are heated by tidal forces. 4. On Saturn’s Moon Titan, what behaves just like water does here on Earth? Methane 5. What types of bodies can have ring systems? Giant planets, Terrestrial planets, Asteroids 6. Astronomers do not believe Callisto was ever geolocically active because there was never any significant tidal heating because it orbits so far from Jupiter. 7. Saturn’s diffuse E ring consists of debris ejected from cryovolvanoes from Enceladus.8. What is the most likely explanation for the origin of irregular moons? They formed independently and were later captured by their host planet. 9. Consider three regular moons of a hypothetical planet: Balrog’s surface is < 1% cratered, with several active volcanoes. Azkaban’s surface has craters which cover about 50% of its rocky surface. Hoth’s icy surface is about 95% cratered with some fresh crates estimated at just 100,000 years old. 10. Jupiter’s moon Io is the most volcanic body in our solar system. This is because: orbital resonances with Europa, and Ganymede allow Jupiter to apply tidal heating to Io’s interior. QUIZ 15 - DWARF PLANETS, ASTEROIDS, & COMETS (CH 12) 1. Asteroids arrange themselves into three different types due to collisions 2. Long-period comets originate in the: Oort cloud. 3. What do Dwarf Planets, Asteroids, and Comets all have in common? They are all planetesimals left over from the formation of the solar system. 4. Objects with the highest orbital inclinations are typically found: in the Kuiper Belt and beyond. 5. Asteroids are classified into three different types based on their composition. 6. Some dwarf planets are also classified as Kuiper Belt Objects 7. Astronomers reclassified Pluto and Ceres as dwarf planets because they didn’t meet which of the following criteria for a “regular” planet?Has “cleared out” its orbit 8. Astronomers detect dwarf planets, asteroids, and distant comets by comparing multiple survey images of the sky to see what moves over time. 9. S and M-type asteroids are rich in iron, minerals, whereas C-type asteroids are rich in lighter volatiles such as carbon, water, and oxygen. 10. Near-Earth asteroids are grouped according to their orbits. Of the three groups, Apollo and Aten pose a potential threat to Earth. 11. The majority of asteroids are located: between the orbits of Mars and Jupiter. 12. Many astronomers consider Pluto and Charon to be a “binary planet” instead of a planet and moon because: The barycenter between Pluto and Charon lies in the space between the two bodies, instead of somewhere inside Pluto.