ASTRO TEST 2 – Flashcards
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Terrestrial Planets
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-Surfaces dramatically altered during the heavy bombardment - accreted from planetesimals of rock and metal
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Jovian Planets
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-large moons formed in surrounding disks of material -formed in regions cold enough for water to freeze -formed in a region of the solar system with lower orbital speeds -ejected icy planetesimals that are now Oort could comets - accreted from icy planetesimals
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Nebular Theory
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Theory that the solar and stellar systems were developed from a primeval nebula
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Rank these materials based on their abundance in the solar nebula, from Highest to lowest: -rock -helium -hydrogen compounds -metals
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-helium -hydrogen compounds -rocks -metals
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Rank these materials from left to right based on the temperature at which each would condense into a solid, from highest to lowest: -rock -hydrogen and helium gas -hydrogen compounds -metals
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-Metals -rock -hydrogen compounds -hydrogen and helium gas
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What substances were found within the inner 0.3 AU of the solar system before planets began to form?
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Rocks, metals, hydrogen compounds, Hydrogen, helium (ALL IN GASEOUS FORM)
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What substances existed as solid flakes within the inner 0.3 AU of the solar system before planets began to form?
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None
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Where would you expect terrestrial planets to form in the solar nebula?
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Anywhere between 0.3 AU and the frost line
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The Jovian Planets are thought to have formed as gravity drew hydrogen and helium gas around planetesimals made of:
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Rocks, metals, and ices
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The nebular theory also predicts that the cloud should heat up as it collapses. What physical law explains why it heats up?
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The law of conservation of energy
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The nebular theory also predicts that the cloud will flatten into a disk as it shrinks in size... What explains why the collapsing clouds should form a disk?
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Colliding Particles exchange angular momentum and, on average, end up with the rotation pattern for the cloud as a whole
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The solar system has 2 types of planets, terrestrials and Jovian. According to the nebular theory, why did terrestrial planets form in the inner solar system and Jovian planets in the outer solar system?
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Iced condensed only in the outer solar system, where some icy planetesimals grew large enough to attract gas from the nebula, while only metal and rock condensed in the inner solar system, making terrestrial planets
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How many of the planets orbit the Sun in the same direction as Earth does?
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All
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What are Jupiter's main ingredients?
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Hydrogen and Helium
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Are there any exceptions to the rule that planets rotate with small axis tilts and in the same direction as they orbit the Sun?
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Venus and Uranus
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Planetary Orbits in our solar system are:
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Fairly circular and in the same plane
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The composition of the solar nebula was 98%
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Hydrogen and Helium
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Which of the following did not occur during the collapse of the solar nebula?
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Concentrating dense materials nearer the Sun
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List the major steps of solar system formation in the correct order?
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Collapse, condensation, accretion
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Leftover ice-rich planetesimals are called
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Comets
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What unusual about our moon?
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It's surprisingly large relative to the planet it orbits
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About how old is our solar system?
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4.5 billion years
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A rock that contains equal amounts of potassium-40 and argon-40
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t= 1.25 x 10^9 years
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A rock that contains fifteen times as much argon-40 as potassium-40
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t=5.00 x10^9 years
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Rank these planets based on their expected cool rates, from fastest cooling to slowest cooling -Venus -Mars -Mercury -Earth
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Mercury,Mars, Venus, Earth
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Rank these planets based on the amount of time the surface of the planet has had a moderate to high level of volcanic/tectonic activity, from longest to shortest -Earth -Mercury -Mars
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Earth,Mars,Mercury
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Rank these Planets from left to right based on their atmospheric pressure at the surface, from highest to lowest - Earth - Mercury - Venus - Mars
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Venus, Earth, Mars, Mercury
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Rank these planets based on the total amount of gas in their atmospheres, from most to least -Venus -Mercury -Mars -Earth
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Venus, Earth, Mars, Mercury
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Rank these planets based on their total amount of infrared-absorbing greenhouse gases in their atmospheres: -Mars -Venus -Earth -Mercury
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Venus, Earth, Mars, Mercury
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Venus
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-Almost no surface winds -Runaway Greenhouse effect -Sulfuric Acid Clouds
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Earth
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-UV absorbing stratosphere -Atmosphere composed primarily of nitrogen
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Mars
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-Global dust storms -Extremely low density atmosphere
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Which heat source continues to contribute to Earth's internal heat?
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-Radioactive Decay
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In general, what kind of terrestrial planet would you expect to have the thickest lithosphere?
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-A small planet
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Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity?
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Size
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What do we conclude if a planet has few impact craters of any size?
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Other geological processes have wiped out craters
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How many of the five terrestrial worlds are considered geologically dead
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2
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Which of the following is a strong greenhouse gas?
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Water vapor
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Which describes our understanding of flowing water on Mars?
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It was important once, but no longer
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Which terrestrial world has the most atmospheric gas?
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Venus
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The oxygen in Earth's atmosphere was released by
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Life
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Where is the most CO 2 that has out gassed from Earth's volcanoes
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Locked up in rocks
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Could a solar system like ours have formed with the first generation of stars after the Big Bang?
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No,there would not have been enough metals and rock to form terrestrial planets.
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Why do we think the inner planets became more sense than the outer planets?
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The inner nebula was so hot that only metals and rocks were able to condense
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Inside the frost line
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too hot for Hydrogen compounds to form ices
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Outside the frost line
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Cold enough for ices to form
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Planetesimals
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A minute planet, a body that could or did come together with many others under gravitation to form a planet
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What do we think first caused tiny solar bits of material in the solar nebula to accrete and stick together ?
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Surface forces
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Accretion
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Gravity draws planetesimals together to form planets
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When the first solid bits in the solar nebula became large enough to be called planetesimals, what began to increase their growth rate?
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Gravity
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Where do asteroids Come from?
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Leftover planetesimals from the inner solar system
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Where do comets comes from?
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Leftover planetesimals from the outer solar system
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Radiometric dating can be used to determine the amount of time since
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A rock last solidified
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Core
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High density; nickel and iron
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Mantle
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Moderate density; minerals with silicon, oxygen
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Crust
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Lowest density; granite, basalt
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What is necessary for a differentiation to occur in a planet?
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-It must be a mix of materials of different density -Material inside must be able to flow
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Sources of Internal Heat
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1) Gravitational potential energy of accreting planetesimals 2) Differentiation 3) Radioactivity
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Where did Earth's interior heat come from?
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-Impacts as Earth was accreting -Radioactivity
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What are Jovian planets made of?
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Jupiter and Saturn are made of Hydrogen and Helium mostly, Uranus and Neptune are made of mostly hydrogen compounds mixed with metal and rock
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Io
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The most geologically active world we know due to its constant volcanism because of tidal heating keeping its interior heat
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Europa
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Sub-Surface ocean
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Titan
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Thick atmosphere and heavy erosion
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Triton
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Captured by Neptune, same composition as Pluto
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Why is Earth Geologically active?
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Earth retains internal heat because of its size, this heat keeps the lithosphere thin ensuring active surface geology
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What 4 processes shape Earths surface?
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1)Volcanism 2)Plate Tectonics 3)Erosion 4)Impact Cratering
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Why did Mars change?
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Mars atmosphere must have once been thicker with a stronger greenhouse effect, so it must have lost atmospheric gas.
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Why is Venus so hot?
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Venus' extreme surface heat is a result of its thick carbon dioxide atmosphere, creating a very strong greenhouse effect
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What Unique features of Earth are important for life?
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1) Surface liquid water 2) Atmospheric oxygen 3) Plate tectonics 4) Climate stability
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What features of our solar system provide clues to how it formed?
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- the sun planets and moons generally rotate and orbit in a very organized way - the planets divide clearly into 2 groups -the solar system contains vast numbers of asteroids and comets - there are some notable exceptions to these general patterns
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Why are there 2 major types of planets?
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-The inner region was so hot, only metal and rock could condense into tiny, solid grains. Eventually these accreted into larger planetesimals to make the terrestrial planets - Beyond the frost line, cooler temperatures also allowed more abundant hydrogen compounds to condense into ice
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What is the largest asteroid in the asteroid belt?
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Ceres
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What is Pluto's largest moon?
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Charon
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Name 4 major greenhouse gases
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1)water vapor 2)carbon dioxide 3)methane 4)ozone
