ASTRONOMY 207 MIDTERM 4 ~ UOFC QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+
5) Why do asteroids and comets differ in composition?
A) Asteroids formed inside the frost line, while comets formed outside.
B) Asteroids and comets formed at different times.
C) Comets formed from the jovian nebula, while asteroids did not.
D) Comets are much larger than asteroids.
E) Asteroids are much larger than comets. Ans✓✓✓A) Asteroids
formed inside the frost line, while comets formed outside.
Why aren't small asteroids spherical in shape?
A) The strength of gravity on small asteroids is less than the strength of
the rock.
B) Small asteroids have odd shapes because they were all chipped off
larger objects.
C) Large asteroids were once molten and therefore became spherical, but
small asteroids were never molten.
D) Large asteroids became spherical because many small collisions
chipped off pieces until only a sphere was left; this did not occur with
small asteroids. Ans✓✓✓A) The strength of gravity on small asteroids
is less than the strength of the rock.
Where are the Trojan asteroids located?
A) surrounding Jupiter
,B) along Jupiter's orbit, 60° ahead of and behind Jupiter
C) in the center of the asteroid belt
D) on orbits that cross Earth's orbit
E) on orbits that cross Mars's orbit Ans✓✓✓B) along Jupiter's orbit, 60°
ahead of and behind Jupiter
How do we know that there are large gaps in the average distances of
asteroids from the Sun (within the asteroid belt)?
a) We can see the gaps through telescopes.
b)We can identify the gaps by looking for stellar occultations in which
an asteroid passed in front of a star as seen from Earth.
c) We have not actually detected any gaps, but theory says they must
exist.
d) We know the gaps must be present to explain how our spacecraft have
successfully navigated the asteroid belt without suffering collisions.
e) We notice gaps on graphs showing the distribution of asteroids with
different orbital periods. Ans✓✓✓e) We notice gaps on graphs showing
the distribution of asteroids with different orbital periods.
The number of comets in the Oort cloud is probably about
A) a thousand.
B) a million.
C) a billion.
D) a trillion.
E) a quintillion. Ans✓✓✓D) a trillion.
, Which of the following does not lend support to the idea that Pluto is a
Kuiper-belt object?
A) Pluto has a cometlike composition and density.
B) Pluto is regarded by many to be a planet.
C) Some asteroids have their own moons.
D) Pluto has a more eccentric orbit than other planets.
E) Some known Kuiper-belt objects are hundreds of kilometers across.
Ans✓✓✓b) Pluto is regarded by many to be a planet.
Based on its orbit, Pluto is a large member of
a) the asteroid belt.
b) the Oort cloud.
c)the moon system around Neptune.
d) an extrasolar planetary system.
e) the Kuiper belt. Ans✓✓✓e) the Kuiper belt.
On average, how often do impactors about 10 km in size, large enough
to produce mass extinction, hit Earth?
A) once every century
B) once every thousand years
C) once every million years
D) once every hundred million years
E) once in Earth's history Ans✓✓✓D) once every hundred million years
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+
5) Why do asteroids and comets differ in composition?
A) Asteroids formed inside the frost line, while comets formed outside.
B) Asteroids and comets formed at different times.
C) Comets formed from the jovian nebula, while asteroids did not.
D) Comets are much larger than asteroids.
E) Asteroids are much larger than comets. Ans✓✓✓A) Asteroids
formed inside the frost line, while comets formed outside.
Why aren't small asteroids spherical in shape?
A) The strength of gravity on small asteroids is less than the strength of
the rock.
B) Small asteroids have odd shapes because they were all chipped off
larger objects.
C) Large asteroids were once molten and therefore became spherical, but
small asteroids were never molten.
D) Large asteroids became spherical because many small collisions
chipped off pieces until only a sphere was left; this did not occur with
small asteroids. Ans✓✓✓A) The strength of gravity on small asteroids
is less than the strength of the rock.
Where are the Trojan asteroids located?
A) surrounding Jupiter
,B) along Jupiter's orbit, 60° ahead of and behind Jupiter
C) in the center of the asteroid belt
D) on orbits that cross Earth's orbit
E) on orbits that cross Mars's orbit Ans✓✓✓B) along Jupiter's orbit, 60°
ahead of and behind Jupiter
How do we know that there are large gaps in the average distances of
asteroids from the Sun (within the asteroid belt)?
a) We can see the gaps through telescopes.
b)We can identify the gaps by looking for stellar occultations in which
an asteroid passed in front of a star as seen from Earth.
c) We have not actually detected any gaps, but theory says they must
exist.
d) We know the gaps must be present to explain how our spacecraft have
successfully navigated the asteroid belt without suffering collisions.
e) We notice gaps on graphs showing the distribution of asteroids with
different orbital periods. Ans✓✓✓e) We notice gaps on graphs showing
the distribution of asteroids with different orbital periods.
The number of comets in the Oort cloud is probably about
A) a thousand.
B) a million.
C) a billion.
D) a trillion.
E) a quintillion. Ans✓✓✓D) a trillion.
, Which of the following does not lend support to the idea that Pluto is a
Kuiper-belt object?
A) Pluto has a cometlike composition and density.
B) Pluto is regarded by many to be a planet.
C) Some asteroids have their own moons.
D) Pluto has a more eccentric orbit than other planets.
E) Some known Kuiper-belt objects are hundreds of kilometers across.
Ans✓✓✓b) Pluto is regarded by many to be a planet.
Based on its orbit, Pluto is a large member of
a) the asteroid belt.
b) the Oort cloud.
c)the moon system around Neptune.
d) an extrasolar planetary system.
e) the Kuiper belt. Ans✓✓✓e) the Kuiper belt.
On average, how often do impactors about 10 km in size, large enough
to produce mass extinction, hit Earth?
A) once every century
B) once every thousand years
C) once every million years
D) once every hundred million years
E) once in Earth's history Ans✓✓✓D) once every hundred million years
