astronomy exam 2 Flashcards
T/F: With the exception of Venus, planetary surface temps decrease at greater. distances from the sun
True
t/f: Pluto is part of the Oort Cloud
False
t/f: within the frost line, planetesimals were composed entirely of rock, and outside the frost line, planetesimals were composed entirely of ice
false
An object orbiting a larger object that orbits the sun is called a
moon
between the orbits of mars and Jupiter lies a place called the
frost line
what do we mean by accretion in the context of planet formation
the growth of planetesimals from smaller solid particles that collided and stuck together
The frost line is between the orbits of which two planets
Mars & Jupiter
T/F: The more massive planets in the solar system tend to be less dense than the lower mass planets
True
according to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size
the law of conservation of angular momentum
which of the following are relatively unchanged fragments from the early period of planet building in our solar system
Oort clouds comets, asteroids, Kuiper Belt comets
T/F: all the planets in the solar system have at least one moon
False
suppose you start with 1 kg of radioactive substance that has a half-life of 10 years. which of the following statements will be true after 20 years pass
you’ll have .25 kg of the radioactive substance remaining
suppose you view the solar system from high above earth’s North Pole. which of the following statements about planetary orbits will be true?
all the planets orbit counterclockwise around the sun
in essence, the solar nebular theory states that
our solar system formed from the collapse of an interstellar cloud of gas and dust
according to our theory of solar system formation, what are asteroids and comets?
leftover planetesimals that never accreted into planets
which of the following is not a characteristic of the inner planets
they have substantial atmosphere
in which part of the solar system is Pluto found
the Kuiper belt
T/F: Jupiter and the other gas giants formed close to the sun and migrated outward
False
where are most of the known asteroids found?
between the orbits of mars and Jupiter
based on studies of the composition of stars and interstellar gas clouds, what was the approximate chemical composition of the solar nebula
98% hydrogen
t/f: earth is the only planet in the solar system known to have active plate tectonics across its entire surface
true
which of the following most likely explains why Venus does NOT have a global magnetic field like earth
its rotation is too slow
rank the five terrestrial worlds in order of size from smallest to largest
Moon, Mercury, Mars, Venus, Earth