Astronomy Midterm 2 Exam Questions Correctly Answered.
When did the objects that we now see as asteroids and comets form in the solar system? - CORRECT ANSWER After solid particles condensed from the gas but before the planets finished forming.
Which of the following statements was true beyon...
Astronomy Midterm 2 Exam Questions
Correctly Answered.
When did the objects that we now see as asteroids and comets form in the solar system? - CORRECT
ANSWER After solid particles condensed from the gas but before the planets finished forming.
Which of the following statements was true beyond the frost line (but not interior to it)? - CORRECT
ANSWER It was cold enough for hydrogen compounds to condense into ices.
Which of the following is thought to explain many of the "exceptions to the rules" of our solar system? -
CORRECT ANSWER giant impacts
Based on what the nebular theory tells us about the formation of our own solar system, what does the
theory predict for the possibility of other planetary systems? - CORRECT ANSWER Planetary systems
should be common.
What are four key features of our solar system that any theory of solar system formation must be able
to explain? - CORRECT ANSWER Planets fall into two major categories.
There are clear patterns to the rotation and orbits of large bodies in the solar system.
There are vast numbers of asteroids and comets.
There are a few notable exceptions to the rules.
We expect a scientific theory to be able to make predictions that can be tested. Which of the following is
a prediction of the nebular theory that has been verified by observations? - CORRECT ANSWER Many
stars should have planets
The "giant impact hypothesis" refers to the idea that ___________. - CORRECT ANSWER our Moon
formed when a Mars-size object collided with the young Earth.
What substances were found in the innermost regions (within about the inner 0.3 AU) of the solar
system before planets began to form? - CORRECT ANSWER rocks, metals, hydrogen compounds,
hydrogen, and helium, all in gaseous form
,What substances existed as solid flakes within the innermost regions (within about the inner 0.3 AU) of
the solar system before planets began to form? - CORRECT ANSWER none
Where would you expect terrestrial planets to form in the solar nebula? - CORRECT ANSWER anywhere
between the innermost regions (within about the inner 0.3 AU) and the frost line
The jovian planets are thought to have formed as gravity drew hydrogen and helium gas around
planetesimals made of __________. - CORRECT ANSWER rocks, metals, and ices
Observations show that interstellar clouds can have almost any shape and, if they are rotating at all,
their rotation is not perceptible. However, the nebular theory predicts that a cloud will rotate rapidly
once it shrinks to a relatively small size. What physical law explains why a collapsed cloud will rotate
rapidly? - CORRECT ANSWER the law of conservation of angular momentum
The nebular theory also predicts that the cloud should heat up as it collapses. What physical law explains
why it heats up? - CORRECT ANSWER law of conservation of energy
The nebular theory also predicts that the cloud will flatten into a disk as it shrinks in size. Which of the
following best explains why the collapsing cloud should form a disk? - CORRECT ANSWER Colliding cloud
particles exchange angular momentum and, on average, end up with the rotation pattern for the cloud
as a whole.
As you've seen, the nebular theory predicts that a cloud that gives birth to planets should have the
shape of a spinning disk. Which observable property of our solar system supports this prediction? -
CORRECT ANSWER All the planets orbit the Sun in the same direction and in nearly the same plane.
The solar system has two types of planets, terrestrial 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? -
CORRECT ANSWER Ices 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.
Based on the nebular theory as it explains our own solar system, which of the following should we
expect to be true for other star systems?
,Planetary systems will always have four terrestrial planets and four jovian planets.
Planetary systems should generally have all planets orbiting in nearly the same plane.
Many extrasolar planets should fall into the terrestrial or jovian categories.
Planetary systems should be common.
Some planetary systems will have terrestrial planets that orbit their star in a direction opposite to the
orbital direction of the jovian planets.
Jovian planets always form farther from their star than terrestrial planets. - CORRECT ANSWER Planetary
systems should generally have all planets orbiting in nearly the same plane.
Many extrasolar planets should fall into the terrestrial or jovian categories.
Planetary systems should be common.
Jovian planets always form farther from their star than terrestrial planets.
Two hypothetical discoveries in Part A deal with moons that, like Earth's moon, are relatively large
compared to their planets. Which of the following best explains why finding 1 planet with such a moon
is consistent with the nebular theory, while finding 6 planets with such moons is not consistent? -
CORRECT ANSWER Unusually large moons form in giant impacts, which are relatively rare events.
Consider the hypothetical discovery from Part A reading: "A star's 5 terrestrial planets orbit in the
opposite direction of its 3 jovian planets." This discovery would be inconsistent with the nebular theory
because the theory holds that __________. - CORRECT ANSWER all the planets formed in a rotating,
disk-shaped nebula
Consider the hypothetical discovery from Part A reading: "Beyond its jovian planets, a star has two ice-
rich objects as large as Mars." This discovery is consistent with the nebular theory, because this theory
predicts that _________. - CORRECT ANSWER this might have happened in our own solar system if it had
taken longer for the solar wind to clear the solar nebula
Consider the three items from Part A that are not relevant to the giant impact hypothesis. As you'll learn
in later chapters, the lack of volcanoes is a result of the Moon's relatively small size. But what explains
the other two items — the Moon's synchronous rotation and gradually increasing distance from Earth? -
CORRECT ANSWER Both are results of tidal interactions between the moon and earth
, As discussed in the Extraordinary Claims box, when the giant impact idea was first proposed, it was
generally thought to be so unlikely that it wasn't seriously considered until decades alter, after the
Apollo missions to the Moon. What key piece of scientific understanding was missing that made it seem
so unlikely when first proposed? - CORRECT ANSWER An understanding of the number and size of
leftover planetesimals in the early solar system.
The verdict at the end of the Extraordinary Claims box says "Likely correct, though may never be
possible to prove definitively." In the context of models, which of the following best explains this
verdict? - CORRECT ANSWER A model that precisely reproduces major characteristics of the Moon
would seem likely correct, but we can't go back in time to see that it actually happened that way.
While we may never be able to prove that our Moon really formed in a giant impact, which of the
following would give scientists greater confidence that the model is correct? Select all that apply.
Finding evidence that other giant impacts occurred in our solar system, with a total number of impacts
consistent with what models of solar system formation lead us to expect.
Creating more sophisticated models of the giant impact that correctly predict many detailed
characteristics of the Earth and Moon.
Smashing together two glass marbles in a laboratory and then gluing the remnants together to make
marbles that have the same size ratio as the Earth and Moon.
Having the giant impact model endorsed by a dozen Nobel prize winners.
Observing evidence of recent giant impacts in other solar systems that are currently in the process of
formation. - CORRECT ANSWER Finding evidence that other giant impacts occurred in our solar system,
with a total number of impacts consistent with what models of solar system formation lead us to expect.
Creating more sophisticated models of the giant impact that correctly predict many detailed
characteristics of the Earth and Moon.
Observing evidence of recent giant impacts in other solar systems that are currently in the process of
formation.
Our solar system was created by the gravitational collapse of the - CORRECT ANSWER Solar Nebula
Our Moon was most likely formed by a collision between Earth and a Mars-sized - CORRECT ANSWER
planetesimal
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