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164 Cards in this Set
- Front
- Back
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Why must the universe have been very uniform for the first million years?
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If the whole universe was once a concentrated point of energy, it must have started out uniform.
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This graph shows how commonly the measured irregularities of different sizes occur in the cosmic microwave background radiation. What size irregularity is the most common?
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1 degree
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(a) Why can't an open universe have a center?
(b) Why can't a closed universe have a center? |
a) It is infinite.
b) It has no edge |
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The early universe was which of the following?
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hot and at high density
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If the average density of the universe is greater than the critical density, the universe is which of the following?
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closed
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What are the characteristics of the spectrum of the cosmic background radiation?
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It is a black body curve with a wavelength of maximum intensity of about one millimeter and is a continuous spectrum that is redshifted into the microwave band.
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This diagram depicts the present universe as it appears from our galaxy (center). What does the inner edge of the outer pink ring represent?
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the recombination event
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According to the WMAP (Wilkinson Microwave Anisotropy Probe) results, what is the nature of our universe?
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Xxx all of the below
The universe is 4% baryonic matter, 23% dark matter, and 73% dark energy. The universe is about 13.7 billion years old. Inflation occurred everywhere early in the first second of expansion. The universe is flat, accelerating, and will expand forever. |
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What evidence is there that the universe is flat?
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The density of the universe seems to be about the critical density.
Inflation predicts a flat universe. Dark energy appears to make up about 2/3 of the universe. xxx all of the above |
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This is a map of the locations of nearly 70,000 galaxies extending out to about 3 billion light years. Why are there two large wedge-shaped empty regions at the top and bottom of this map?
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The Milky Way blocks our view.
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(a) What evidence is there that the universe is expanding?
b)What evidence shows that the universe began with a big bang? |
a) the redshifts of all distant galaxies
b) If the universe is expanding, the expansion must have had a beginning. The universe has a finite age. The cosmic microwave background radiation is proof of the big bang. Xxx All of the above are evidence. |
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(a) Rank the following events in the order of their occurrence in the history of the universe: big bang, birth of galaxies, birth of matter and atoms, inflation.
(b) Rank the forces of nature in the order that they began to act independently (there is one tie): electromagnetism, gravity, strong nuclear force, weak nuclear force. (c) Rank the following types of universes in order of increasing necessary densities of the universe: closed, flat, open. |
a) earliest: big bang
inflation birth of matter and atoms latest: birth of galaxies b) earliest: gravity Strong nuclear force electromagnetism latest: weak nuclear force c) least: open flat greatest: closed |
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(a) Which is a reason that Earth being at the center of the universe does not seem likely?
(b) If Earth is not the center of the universe, then how can all galaxies appear to be moving away from us? |
a) Earth is not even the center of our solar system.
Our sun is not the center of our galaxy. Xxx Both are good reasons. b) All galaxies are moving away from each other. Residents in all galaxies would observe all other galaxies moving away from them. Xxx Both of the above are reasons. |
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When the universe was one second old, all the initial protons and neutrons had already formed, but electrons had not yet formed. Why?
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The average photon energy was too low to produce more protons and neutrons, and too high to produce electrons.
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Where did the big bang occur?
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everywhere
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Which question is not answered by the standard big bang theory?
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Why is the universe so very close to flat and why is the cosmic background radiation so smooth?
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What observational evidence implies that most of the universe is dark matter?
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Large-scale gravitational fields are much stronger than can be accounted for by observed matter
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What forms of normal matter existed when the universe was three minutes old?
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Hydrogen nuclei, helium nuclei, a trace of lithium nuclei, and independent electrons were present.
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What does the information displayed in this figure reveal?
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The universe is expanding.
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If the universe has no edge, then it must also have none of which of the following?
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center
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What evidence do we have that the universe is expanding?
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The amount of redshift in the spectra of distant galaxies is proportional to their distance.
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If the Hubble constant is 100 km/s/Mpc, to the first approximation how old is the universe?
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The amount of redshift in the spectra of distant galaxies is proportional to their distance.
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What assumptions are made in Olber's paradox?
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The universe is infinite and uniformly filled with stars.
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What was found in 1998 by two independent teams of astronomers that observed supernovae type Ia to determine galactic distances in order to find by how much gravity has slowed the rate of expansion of the universe?
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The universe's rate of expansion is increasing.
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(a) Recent observations seem to show that the rate of expansion of the universe is
(b) What is the evidence for the answer to the previous question? |
a) speeding up (accelerating)
b) Using type Ia supernovae as standard candles. |
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(a) What does the darkness of the night sky tell you about the universe?
(b) Why does the darkness of the night sky tell you what it does about the universe? |
a) It is not infinitely old.
b) If the universe was infinitely old, light from stars at the end of every line of sight would eventually reach you. |
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What cosmological inference can you draw from the darkness of the night sky?
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The universe is not infinitely old.
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What alteration to the standard big bang models solves both the problems of a nearly flat universe and smooth cosmic background radiation?
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sudden rapid expansion early during the first second of the universe
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(a) Which of the following is true for the present density of the universe?
(b) Why is it difficult to determine the present density of the universe? |
a) It is not precisely known.
b) We think that much of the matter and energy in the universe is "dark." |
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Quasars have redshifts as high as 6. What has a redshift of about 1,100?
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the cosmic background radiation and radiation from the recombination event
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In the figure, visible wavelengths are in blue and radio wavelengths are in red.
(a) Why do some of the galaxies in the above figure have elongated, slightly curved images? (b) What is the reason for the observation in the previous question? (c) What does the observation in the previous question tell you about the universe? |
a) gravitational lensing
b)There is a lot of dark matter in the cluster. c) There is much more mass than is observed. |
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Why couldn't atomic nuclei exist when the universe was younger than 2 minutes old?
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The universe was too hot.
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Raisin Bread
(a) Choose a raisin as your vantage point. As the bread bakes, how do the movements of the nearest and farthest raisins compare? (b) How is the raisin bread analogy like the expansion of the Universe? (c) The farther a raisin is from the selected raisin, the faster it moves. |
a) The farthest raisin moves a greater total distance
b) The raisins move apart as the bread expands. c) true |
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Why do astronomers think that most of the dark matter cannot be baryonic?
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The measured abundances of deuterium and lithium in distant gas clouds suggest that baryonic dark matter can account for not more than 4% of the critical density and dark matter must make up almost 30% of the critical density.
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Origin of Cosmic Redshifts
(a) What happens to the wavelength of light as the universe expands? (b) In the balloon model, the rubber of the balloon represents what? (c) Where is the center of expansion for the universe? |
a) It is stretched
b) The fabric of spacetime c) There is no center - the universe expands equally everywhere |
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Which type of universe has a rate of expansion approaching a positive value as time approaches infinity?
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an open universe
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(a) Rank the following elements in order of their creation during the first few minutes after the big bang: beryllium, helium, hydrogen, lithium.
(b) Rank the above elements in order of decreasing mass, from heaviest to lightest. |
a) earliest: hydrogen
helium lithium latest: beryllium b) heaviest: beryllium lithium helium lightest: hydrogen |
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What is meant by the term "observable universe"?
*************END CHAPTER 11*************** |
the part of everything that exists that we can see
*************END CHAPTER 11*************** |
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(a) Solid particles sticking together is called which of the following?
(b) Particles growing by addition of material an atom or molecule at a time from a surrounding gas is called which of the following? |
a) accretion
b) condensation |
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(a) How do you think the age of another planetary system would compare to the age of our solar system?
(b) What is the reason for the answer to the previous question? |
a)It should be similar.
It should be older. It should be younger. Xxx It could be any of the above. b) Our solar system is about halfway through its evolution, and our sun is probably a second- or third-generation star. |
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(a) Which planets are more dense?
(b) Based on the solar nebula theory, what is the reason for the observation in the previous question? |
a) terrestrial planets
b) Terrestrial planets formed from solid material that condensed out of the solar nebula close to the sun, where it was too hot for them to capture gases. Jovian planets started out with solid material as well, and were far enough from the sun for a layer of ice to form, after which they became massive enough to capture slower-moving gases. Xxx Both of the above are true. |
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How is the solar nebula theory supported by the motion of solar system bodies?
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Xxx all of the below
All of the planets orbit the sun near the sun's equatorial plane. All of the planets orbit in the same direction that the sun rotates. Six out of seven planets rotate in the same direction as the sun. Most moons orbit their planets in the same direction that the sun rotates. |
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Radiometric dating of rock samples indicates that the solar system formed about 4.56 billion years ago. Which rock samples have this age?
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meteorites
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What is the origin of the atoms of hydrogen, oxygen, and sodium in the perspiration that exits your body during an astronomy exam?
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The hydrogen nuclei were produced a few minutes after the big bang event 13.7 billion years ago, and the oxygen and sodium nuclei were synthesized inside stars more than 4.6 billion years ago.
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Why haven't we detected low-mass planets close to their stars and high-mass planets far from their stars?
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Our techniques are not yet sensitive enough and we have not been observing for a long enough time.
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Why is the dust disk around Epsilon Eridani shown here brighter than the star Epsilon Eridani at far infrared wavelengths?
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The dust disk is cooler and has more surface area than its star.
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In these images you can see the shapes of asteroid Eros and Comet Wild 2. Which of the following can explain why these two small bodies have nonspherical shapes?
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For small bodies, the strength of material is greater than the compression of gravity.
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What evidence do we have that planets form along with other stars?
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Xxx all of the below
At radio wavelengths we detect cool dust disks around young stars. At infrared wavelengths we detect large cool dust disks around stars. At visible wavelengths we see disks around the majority of single young stars in the Orion nebula. At radio wavelengths we detect cool dust disks around young stars and at infrared wavelengths we detect large cool dust disks around stars. |
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What are the general characteristics of the extrasolar planets discovered so far?
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They have high mass and orbit close to their stars.
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Which of the following accurately describes the differentiation process?
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High-density materials sink toward the center and low-density materials rise toward the surface of a molten body.
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(a) Why is the sun's equator nearly in the plane of Earth's orbit?
(b) According to which theory should the sun's equator be nearly in the plane of Earth's orbit? |
a) The planets formed from a disk of gas that surrounded the sun as it formed.
b) the solar nebula hypothesis |
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How do we know that extrasolar planets are orbiting other stars?
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We see a star's light dim as a planet passes in front of the star and detect alternating Doppler shifts in the spectra of some stars.
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(a) Which kind of planet has rings?
(b) What is the reason for the answer to the previous question? |
a) a Jovian planet
b) Jovian planets are more massive. |
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Which properties of the solar system are accounted for in this simple series of three diagrams depicting the solar nebula hypothesis
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Xxx all of the below
the common direction of revolution and rotation of most solar system bodies the planets orbiting the sun in nearly the same plane the common age of the sun and the oldest meteorite minerals the common direction of revolution and rotation of most solar system bodies and the planets orbiting the sun in nearly the same plane |
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What evidence can you cite that planets orbit other stars?
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disks of gas and dust around stars
doppler shifts in the spectra of sun-like stars a decrease in the brightness of a star when a planet crosses in front of it Xxx all of the above |
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According to the solar nebula theory, why are Jupiter and Saturn much more massive than Uranus and Neptune?
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Jupiter and Saturn formed earlier and captured nebular gas before it was cleared out.
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How do astronomers believe the sun came to have less angular momentum than its system of planets?
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The solar wind mass outflow carries angular momentum away from the sun and the sun's magnetic field drags material out in the solar system, transferring angular momentum outward.
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What evidence can you cite that disks of gas are common around young stars?
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infrared observations of T-Tauri stars
bipolar flows from protostars visible and radio observations of stars in the Orion nebula Xxx All of the above are evidence. |
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(a) What produced the iron in Earth's core?
(b) What produced the gold and silver in Earth's crust? |
a) some nuclear fusion in a massive star's core, mostly supernovae
b)supernovae |
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How did the solar nebula get cleared of material
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Xxx all of the below
The radiation pressure of sunlight pushed gas particles outward. The intense solar wind of the youthful sun pushed gas and dust outward. The planets swept up gas, dust, and small particles. Close gravitational encounters with Jovian planets ejected material outward. |
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How did the solar nebula get cleared of material?
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Xxx all of the below
The radiation pressure of sunlight pushed gas particles outward. The intense solar wind of the youthful sun pushed gas and dust outward. The planets swept up gas, dust, and small particles. Close gravitational encounters with Jovian planets ejected material outward. |
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How does the solar nebula theory account for the drastic differences between terrestrial and Jovian planets?
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Xxx all of the below
The temperature of the accretion disk was high close to the sun and low far from the sun. Terrestrial planets formed closer to the sun and are thus made of high-density rocky materials. Jovian planets are large and have high mass because they formed where both rocky and icy materials can condense. Jovian planets captured nebular gas as they had stronger gravity fields and are located where gases move more slowly. |
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Which of the following is NOT a property associated with terrestrial planets?
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They have low density
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Potassium 40 decays to calcium 40 with a half-life of 1.3 billion years. Use this diagram to determine the age of a rock in which only 12.5% of its original potassium 40 remains.
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The rock is 3.9 billion years old.
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(a) What is the separation of material in a planet called?
(b) Why would you expect the process in the previous question to happen? |
a) differentiation
b) More-dense materials should sink to the bottom. Less-dense materials should rise to the top. Very light materials may escape. Xxx all of the above |
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How do asteroids and comets differ?
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Comets contain ices.
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Where are most asteroids located?
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between the orbits of Mars and Jupiter
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(a) How old do astronomers think the solar system is?
(b) How do astronomers estimate the age of the solar system? |
a) almost 5 billion years old
b) from radioactive dating |
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(a) Where in the solar system are asteroids found?
(b) How does the solar nebula theory help you understand the location of asteroids? |
a) mostly in the belt between Mars and Jupiter, but in other orbits as well
b) Many of the asteroids are material that would have formed a terrestrial planet, but could not, due to gravitational pull from Jupiter. Asteroids in places other than the belt are debris left over from the formation of the solar system. Xxx Both of the above are true. |
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Which of the following is the most likely major heat source that melted early formed planetesimals?
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the decay of short-lived unstable isotopes
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Relative Size in the Solar System
(a) How many Earths does it take to stretch across Jupiter? (b) Which planet has the greatest radius? (c) Which planet orbits between Venus and Mars? |
a) 11
b) Jupiter c) Earth |
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(a) What produced the helium in the sun's atmosphere?
(b) What produced the helium in Jupiter's atmosphere? (c) What produced the helium in the sun's core? |
a) it was among the gases from which it formed
b) it was captured directly from the solar nebula c) nuclear fusion |
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(a) Rank the order in which the following substances would condense out the solar nebula: argon, iron, methane, water ice.
(b) Rank the distance from the sun at which the following substances would be found as solids, in order with the closest to the sun first: ammonia, iron, neon, water ice. |
a) first:iron
water ice methane last:argon b) closest to sun: iron water ice ammonia farthest from sun : neon |
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How does the solar nebula theory explain the formation of an asteroid belt between Mars and Jupiter rather than a planet at this location?
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Jupiter formed early and its gravitational influence altered the orbits of nearby accreting planetesimals such that their collisions became destructive rather than constructive.
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(a) Which planet is shown in the figure?
(b) What indicates that this planet formed far from the sun? |
a) Saturn
b) It has rings and therefore must be massive, and massive planets form far from the sun. |
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Compare the two radial velocity curves shown here for the stars 51 Pegasi and Upsilon Andromedae. Why is the curve for Upsilon Andromedae more complex than that of 51 Pegasi?
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Upsilon Andromedae has more than one planet.
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Which is the process that cleared the solar nebula away and ended planet building?
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radiation pressure and solar wind
sweeping up of debris by planets ejection of material by close encounters with planets Xxx all of the above cleared the nebula |
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What is the difference between the processes of condensation and accretion?
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Condensation is the building of larger particles one atom (or molecule) at a time, whereas accretion is the sticking together of larger particles.
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(a) Which is in the early stages of star formation?
(b) Which may be home to planets that have already formed? *************END CHAPTER 12*************** |
a) a hot disk of gas and dust
b) a cold dust or debris disk *************END CHAPTER 12*************** |
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What distinguishes Earth's inner core from its outer core?
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The inner core is solid, and the outer core is liquid.
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Jupiter's ring appears dark in back-scattered light, yet appears bright in forward-scattered light. What does this tell us about the particles that make up Jupiter's ring?
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The particles' average diameter is a few micrometers and are most likely dust.
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Why are Europa, Ganymede, and Callisto necessary for the continued heating of Io?
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These moons periodically tug on Io and keep its orbit elliptical.
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Why are the surface temperatures of Venus and Earth so very different?
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Venus is too close to the sun to have liquid water oceans and Earth is far enough from the sun to have liquid water oceans.
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In which way does Saturn differ from Jupiter?
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Saturn has a smaller zone of liquid metallic hydrogen.
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What evidence do we have that Mars had much more liquid water at its surface in the past than it has today?
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Xxx all of the below
The deuterium-hydrogen ratio is 5.5 times as high as on Earth. Martian meteorites must have formed from lava that was up to 1.8% water. We see large, dry outflow channels and valley networks on the surface of Mars. The deuterium-hydrogen ratio is 5.5 times as high as on Earth and Martian meteorites must have formed from lava that was up to 1.8% water. |
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How does a thin planetary ring retain its shape?
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Small moons orbiting just inside and outside the rings shepherd the ring particles.
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What evidence supports the model of Jupiter's Galilean satellites forming in a mini accretion disk around Jupiter?
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The density trend of these four moons is highest close to Jupiter and decreases with distance and the two inner moons are much smaller than the two outer moons of this group.
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What is the Roche limit?
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The maximum distance from a planet at which planetary rings can exist.
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What drives the moving plates of Earth's crust?
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convection in Earth's rocky mantle
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Jupiter's mass is approximately 0.001 solar masses. How is the mass of Jupiter determined?
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We use Newton's form of Kepler's third law and the period and semimajor axis of Callisto's orbit around Jupiter.
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What evidence do we have that Io's crust and lava is mostly silicate rock rather than sulfur compounds?
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Some mountains on Io are much higher than any mountains on Earth and much of the lava flowing from Io's volcanoes is hotter than Earth lava.
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How do we know what the surface of Venus looks like?
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Radar mapping at radio wavelengths allows us to determine surface elevations.
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Why does the moon have large maria on the Earth-facing side, yet no large maria on the opposite side?
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The moon's crust is thicker, or elevations higher, on the far side.
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What single factor resulted in the moon today being so very much different than present-day Earth?
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the moon's small size
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Which gas is most abundant in the atmospheres of Venus and Mars?
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carbon dioxide (CO2)
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a) Rank each atmospheric composition in order of when it occurred on Earth, oldest first: carbon dioxide, hydrogen and helium, nitrogen and oxygen.
(b) Rank the following atmospheric gases in order of their abundance in Earth's current atmosphere: carbon dioxide, nitrogen, oxygen, water vapor. |
a) oldest :hydrogen and helium
carbon dioxide youngest: nitrogen and oxygen b) most: nitrogen oxygen carbon dioxide least: water vapor |
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What erases the impact craters on Earth and is responsible for most of the landforms that we see?
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plate tectonics and water and ice erosion
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Where did the particles in Saturn's rings come from?
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They are material ejected from the moons by impacts.
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Why is the surface temperature of Venus higher than that of any other planet?
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It has an extreme greenhouse effect.
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What produced the oxygen in Earth's atmosphere?
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plants
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How do we find the relative ages of the moon's maria and highlands?
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by counting the number of impact craters
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How can Titan have a nitrogen-methane atmosphere with a surface pressure 1.5 times that of Earth's atmosphere, whereas the larger and more massive Ganymede has no atmosphere at all?
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Titan is farther from the sun and thus colder than Ganymede.
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(a) Which is not true about ozone?
(b) Which is not true about the decreasing density of the stratospheric ozone layer? |
a) It is a gas in the stratosphere.
It absorbs ultraviolet radiation from the sun. It is a pollutant produced by automobile emissions. Xxx All of the above are true. b) There is evidence of an actual hole in the ozone layer. It was caused by chemicals released into the atmosphere by industrial processes. It could cause public health problems like increased rates of skin cancer. Xxx All of the above are true. |
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Why would a decrease in the density of Earth's ozone layer cause public health problems?
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The ozone layer blocks ultraviolet light from the sun, and ultraviolet light causes skin cancer.
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How can astronomers estimate the ages of the streambeds on Mars?
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By examining nearby cratered surfaces
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Which of the following is true about Earth's ozone layer?
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It is located at an altitude of about 25 km and a hole develops every October over Antarctica.
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(a) Why is the figure a typical view of the surface of Earth?
(b) What about the above figure makes Earth unique among terrestrial planets? |
a) Earth's surface is mostly covered by water.
b) Earth is the only terrestrial planet with oceans. |
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What evidence do we have that Earth differentiated?
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The curved paths of seismic waves indicate that the interior density of Earth is greater than can be explained by compression alone.
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What is peculiar about the orbits of Neptune's moons Triton and Nereid?
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Triton's orbit is in the retrograde direction, and Nereid's orbit is large and very elliptical.
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Why might we expect Venus and Earth to be similar?
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Both planets are about the same size, density, and have the same chemical composition.
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What evidence do we have that the surface of Europa is young and active?
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Europa has very few impact craters and the icy crust of Europa is highly reflective.
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How do temperature and pressure vary with depth deep inside Earth?
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Mars has cooled to the point that it no longer has a fluid interior.
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(a) Rank the substances in the above table in order of abundance in Jupiter.
(b) Rank the substances in the above table in order of abundance in Saturn. |
a) most abundant : hydrogen
helium ammonia methane least abundant: water vapor b) most abundant: hydrogen helium methane least : abundant |
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What is the difference between the intercrater plains and the smooth plains that are found on Mercury in terms of time of formation?
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The intercrater plains are older than the smooth plains.
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What keeps small shepherd moons from breaking apart within the Roche limit of a planet?
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The moons must be structurally strong (which means that they are kept from breaking apart by the electrostatic bonds of the moon's material).
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How is the planet Mercury similar to Earth's moon?
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Their surfaces both appear heavily cratered by impacts and their lowland regions were flooded by ancient lava flows.
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Detecting Uranus's Rings
(a) Judging by the light curve shown in this animation, which of Uranus's rings is the most dense? (b) Judging by the light curve shown in this animation, which of Uranus's rings is the widest? (c) The measurement of which characteristic of light was most useful in this discovery? |
a) the outer ring
b) the outer ring c) intensity |
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Rank the stages of the moon's history in the order in which they occurred: cooling, cratering, differentiation, lava flooding, slow surface evolution.
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first :differentiation
cooling cratering lava flooding last: slow surface evolution |
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Seismic Waves
(a) From an earthquake across the globe from a seismograph station, only P waves register. Why? (b) Which of these are the same regardless of the location of the seismograph station? |
a) S waves don't propagate through the liquid core.
b) The intensity of the waves The time delay from the quake until the waves register The types of waves received Xxx None of these |
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What gives Saturn's rings their beautiful structure?
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The gravitational influence of Saturn's moons on the ring particles.
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How did Titan keep an atmosphere when larger Ganymede did not?
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It is twice as far from the sun as Ganymede, so the gases are slower-moving and easier to trap.
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Why does the same side of the moon always face Earth?
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The moon rotates in the same direction that it revolves and the moon's period of rotation is equal to its orbital period.
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What energy source drives the weather that we see on Jupiter?
***********END CHAPTER 13 & 14******************* |
Thermal energy escaping from Jupiter's interior that is still hot from formation.
***********END CHAPTER 13 & 14******************* |
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How does the DNA molecule produce a copy of itself?
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It splits in half down the middle.
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According to the geologic time scale shown here, which of the following lists of fauna is in order (past to present) of their first appearance on Earth?
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fish, amphibians, mammals, birds
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Why are upper-main-sequence stars unlikely sites for intelligent civilizations?
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The short lifetime of such stars allows little time for intelligent life to evolve.
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Which element is the physical basis for life chemistry on Earth?
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carbon
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How can the instructions stored in DNA molecules be changed?
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Xxx all of the below
by chance mismatching of base pairs during cell division by exposure of reproductive cells to radioactive isotopes by exposure of reproductive cells to cosmic rays by chance mismatching of base pairs during cell division and by exposure of reproductive cells to radioactive isotopes |
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Where is the "water hole" that we suspect is a good place to find extraterrestrials?
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between 18 cm and 21 cm wavelengths
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Examine the pessimistic and optimistic estimates in this table. For which variable in the modified Drake equation are we the most certain of its value?
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the number of stars per galaxy
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(a) What is the water hole?
(b) Why is the answer to the above question considered significant? |
a) It is a range of radio wavelengths at which detecting signals of technological origin seems promising.
b) The wavelengths are between those of emission lines of H and OH, which combine to form water. Since water is so important to life, the water hole may be wavelengths that any technological civilization would choose for radio transmissions. |
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Why is interstellar space travel nearly impossible?
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The distances between even the closest stars are huge.
The speed of even the fastest-possible spacecraft is too slow. The amount of fuel that would be needed is too great. Xxx all of the above |
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Why do SETI programs only observe at wavelengths between 1 and 30 centimeters?
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At wavelengths longer than 30 cm, our galaxy emits a lot of interference, and at wavelengths less than 1 cm, our atmosphere is opaque.
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This information was beamed out in the direction of the globular cluster M13 in 1974. If this message is received by intelligent beings on a planet in globular cluster M13, when can we expect to receive their bid on eBay for this primitive tapestry?
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in about 52,000 years
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Rank the following events in the evolution of life on Earth in order of how recently they occurred, with the most recent first: the beginning of the age of humans, the end of the age of dinosaurs, the first birds, the first flowering plants, the first forests, first life on land, origin of life.
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most recent: in the beginning of the age of humans
The end of the age of dinosaurs The first flowering plants The first birds The first forests First life on land least recent: origin of life |
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Other than Earth, where in the solar system is the most likely place to find life?
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Mars
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(a) Which is considered perhaps the most limiting factor in contacting another civilization?
(b) What is the reason for the answer to the previous question? |
a) how long a technological civilization will last
b) The development of technology could become self-destructive; for example, nuclear and biological weapons, or pollution destroying an environment. |
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(a) What kind of information is life based on?
(b) Where is this information stored? |
a) genetic information
b) DNA |
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How do the instructions stored in a DNA molecule at the nucleus of a cell get out to where they are needed to conduct the business of life?
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The instructions are copied and transported by RNA molecules.
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This diagram shows several amino acids linked together. What is given off each time another amino acid joins the chain?
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a water molecule
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Why must the DNA instructions change for a species to survive?
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To adapt to changes in the environment.
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This is a 3.5-billion-year-old fossil stromatolite from western Australia that formed in a shallow sea. Where do the bacteria that form stromatolites get the energy for photosynthesis?
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from the sun
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Why do we suspect that travel between stars is nearly impossible for intelligent life forms?
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Xxx all of the below
The distance between stars in the disk of our galaxy is typically several light years. The maximum speed that can ever be approached is the speed of light. To accelerate to and from high speeds requires a tremendous amount of fuel. The distance between stars in the disk of our galaxy is typically several light years and the maximum speed that can ever be approached is the speed of light. |
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(a) Which kinds of stars are least likely to have planets that could harbor life?
(b) What is the reason for the answer to the above question? |
a) upper-main-sequence stars
b) Hot and bright stars do not live long enough for a planet with Earth-like conditions to develop. |
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How may intelligence have begun?
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by species developing multiple escape strategies
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What is chemical evolution?
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The process of the bonding together of molecules to form progressively more complex molecules that cannot reproduce themselves.
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How does intelligence make a creature more likely to survive?
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The ability to analyze situations and take appropriate action is a survival mechanism.
It makes beings more versatile. Xxx both of the above |
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(a) What is natural selection?
(b) Which is an example of natural selection? |
a) mutations that are favorable to survival in a changing environment being passed on to subsequent generations because the life forms with the mutation survived to pass it on
b) whale fins becoming legs over time as a water environment dries up due to climate change plants developing flowers so they can reproduce more rapidly, as dinosaurs who eat tons of plants a day migrate into the area where the plants grow frat-boys removing themselves from the gene pool by getting killed while doing the beer slide Xxx all of the above |
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What was the significance of the Miller-Urey experiment?
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It showed that complex organic molecules can form naturally.
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(a) Which is chemical evolution?
(b) Which is biological evolution? |
a) simple molecules concentrating into larger, stronger molecules
b) molecules reproducing |
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If the entire history of Earth is compressed to a calendar year, when do humans appear?
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in the evening of December 31st
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How are the instructions for life stored in DNA molecules?
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as a sequence of base pairs
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(a) What would happen to a life form if the information handed down was always the same?
(b) How would this endanger the life form's future? |
a) there would be no mutations
b) Without mutations, the life form cannot adapt to a changing environment. If it cannot evolve, it may become extinct. |
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(a) Where would you have the best chance to find life in the galaxy in the figure below?
(b) What is the reason for the above answer? |
a) stars in the disk
b) Stars near the center of a galaxy move too fast, and are much too close together to be likely to have planets suitable for life. There is also much radiation harmful to life near the center of the galaxy. Stars in the halo are population II, poor in heavy elements, and likely only to have Jovian planets. Stars in the disk are population I, rich in heavy elements, and are more likely to have terrestrial planets. Xxx all of the above |
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(a) Which is not considered a condition for a planet to be suitable for life?
(b) What evidence can you cite as the reason for the answer to the previous question? |
a) the presence of liquid water
moderate temperatures Xxx both of the above; moderate temperatures are necessary for the presence of liquid water b) Earth is the only planet in our solar system with liquid water oceans. |
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How many different bases (A, C, etc.) make up the base pairs of DNA molecules?
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4
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When a cell divides, how does a DNA molecule duplicate its stored information for the two new cells?
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The DNA molecule divides along the long dimension of the ladder, splitting the base pairs. Corresponding new bases attach to each half to form two new identical DNA molecules.
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Rank the factors in the Drake equation in order of how certainly we know them, with the most certain first: the number of stars per galaxy, the fraction of stars with planets, the fraction of life forms that evolve intelligence, the fraction of a star's life during which a technological society survives, the number of communicative civilizations per galaxy.
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most certain: the number of stars per galaxy
The fraction of stars with planets The fraction of life forms that evolve intelligence The fraction of star's life during which a technological society survives least certain: the number of communicative civilizations per galaxy |
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For which variable in the modified Drake equation do we have the greatest difficulty in estimating an accurate and precise value?
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the fraction of a star's life during which a technological society survives
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What evidence do we have that life on Earth began in the sea?
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The oldest fossils are of the remains of ocean creatures.
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What evidence do we have that life on Earth began in the sea?
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The oldest fossils are of the remains of ocean creatures.
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On Earth why is carbon-based life more successful than silicon-based life?
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Carbon molecule chains are stronger and more stable.
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Within what distance would an extraterrestrial civilization have to be in order to have received TV and radio signals emitted from Earth?
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within about 50 light-years
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(a) Where did life first begin?
(b) What evidence is there to support the answer to the previous question? **********END CHAPTER 15 ************************ |
a) in the sea
b) There is no evidence as to where life began. **********END CHAPTER 15 ************************ |
