Astronomy Chapter 6 Terms – Flashcards
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Which of the following did not occur during the collapse of the solar nebula?
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concentrating denser materials nearer the Sun
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The composition of the solar nebula was 98%
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hydrogen and helium.
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According to our theory of solar system formation, what are asteroids and comets?
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leftover planetesimals that never accreted into planets
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Which lists the major steps of solar system formation in the correct order?
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collapse, condensation, accretion
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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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In light of what you've learned about the formation of our own solar system, decide whether the discovery should be considered reasonable or surprising.
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Surprising. According to our current theories, objects that form beyond the jovian planets should include a great deal of ice.
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When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals EXCEPT _________.
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carbon dioxide
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What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
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It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ice to condense.
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Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is __________.
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much larger
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How is Einstein's famous equation, E = mc 2, important in understanding the Sun?
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the Sun generates energy to shine by losing 4 million tons of mass each second
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In what way is Venus most similar to Earth?
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Both planets are nearly the same size.
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Which planet listed below has the most extreme seasons?
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Uranus
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Which of the following is not a major pattern of motion in the solar system?
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Nearly all comets orbit the Sun in same direction and roughly the same plane.
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Which of the following is not a major difference between the terrestrial and jovian planets in our solar system?
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Terrestrial planets contain large quantities of ice and jovian planets do not.
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The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system?
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The diameter of Earth's Moon is about 1/4 that of Earth.
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According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size?
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The law of conservation of angular momentum
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According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size?
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The law of conservation of energy
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According to our present theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?
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It flattened as a natural consequence of collisions between particles in the nebula.
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What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)?
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The temperatures at which various materials will condense from gaseous form to solid form.
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According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is not true?
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The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal.
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Many meteorites appear to have formed very early in the solar system's history. How do these meteorites support our theory about how the terrestrial planets formed?
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The meteorites appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests.
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According to our present theory of solar system formation, how did Earth end up with enough water to make oceans?
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The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars.
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According to our basic scenario of solar system formation, why do the jovian planets have numerous large moons?
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As the growing jovian planets captured gas from the solar nebula, the gas formed swirling disks around them, and moons formed from condensation accretion within these disks.
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Which of the following is not evidence supporting the idea that our Moon formed as a result of a giant impact?
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The Pacific Ocean appears to be a large crater - probably the one made by the giant impact.
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Why are terrestrial planets denser than jovian planets?
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Why are terrestrial planets denser than jovian planets?
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About 2% of our solar nebula consisted of elements besides hydrogen and helium. However, the very first generation of star systems in the universe probably consisted only of hydrogen and helium. Which of the following statements is most likely to have been true about these first-generation star systems?
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There were no comets or asteroids in these first-generation star systems.
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Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By measuring the amount of its decay product (argon-40) present in the rock, you conclude that there must have been 80 micrograms of potassium-40 when the rock solidified. How old is the rock?
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3.75 billion years
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How do scientists determine the age of the solar system?
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Radiometric dating of meteorites
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What is Jupiter's main ingredient?
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hydrogen and helium
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What's unusual about our Moon?
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It's surprisingly large relative to the planet it orbits.
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Leftover ice-rich planetesimals are called
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comets.
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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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In essence, the nebular theory holds that _________.
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our solar system formed from the collapse of an interstellar cloud of gas and dust
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The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from?
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They were produced by stars that lived and died before our solar system was born.
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Compare the graph in (Figure 1) to (Figure 2) , which shows the decay of potassium-40. Which element is more radioactive (undergoes radioactive decay more quickly)?
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uranium-235
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What fraction of the original uranium-235 should be left after 3.5 billion years?
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1/32
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You find a mysterious rock on the ground and determine that 60% of its uranium-235 has been converted into lead-207. What is the most likely origin of the rock, based on its radiometric age?
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It's a volcanic rock nearly a billion years old.
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In light of what you've learned about the formation of our own solar system, decide whether the discovery should be considered reasonable or surprising.
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Surprising. In the process of nebular capture the formation of large number moons at a jovian planet is more likely that at a terrestrial planet.
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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 are exceptions.
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According to modern scientific dating techniques, approximately how old is the solar system?
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4.5 billion years
