ISP 205 Exam #2 MSU (Practice Test)

Which of the following statements best explains why
the planets orbit in nearly a single plane and in the same
direction around the Sun?
1.A It's a mysterious coincidence: the planets form randomly,
so it's a puzzle how they orbit that way.
B The Sun rotates in the same direction, and spun out
the planets as it formed.
C The planets formed from a disk of rotating gas.
D The planets all rotate in same direction as they orbit.

c

Why are rocky planets close to the Sun and gas giants
farther out?
2.A Because rocks settled to the center of the solar nebula
and not farther out.
B Because the center of the solar nebula was too hot for
hydrogen ices to form.
C Because iron atoms preferentially moved to the center
of the solar nebula.
D Because of the Sun's strong magnetic fields.

B (maybe)

What is the leading scenario for the formation of the
Moon?
3.A It formed from the material ejected in a giant impact.
B It formed as an asteroid and was captured by the
Earth.
C It split out of a rapidly rotating Earth.
D It formed from the solar nebula along with the Earth

A

Why did the solar nebula heat up as it collapsed?
4.A As the cloud shrank, its gravitational potential energy
was converted to thermal energy.
B Nuclear fusion occurring in the core of the protosun
produced energy that heated the nebula.
C Radiation from other nearby stars that had formed
earlier heated the nebula.
D Collisions among planetesimals generated friction and
heat.
E The shock wave from a nearby supernova heated the
gas.

A

Why do asteroids and comets differ in composition?
5.A Comets formed from the jovian nebula, while asteroids
did not.
B Asteroids are much larger than comets.
C Comets are much larger than asteroids.
D Asteroids formed inside the frost line, while comets
formed outside.
E Asteroids and comets formed at different times

D

If the freezing point of ices of all types was at a much
lower temperature, what change would that imply for the
formation of our solar system?
6.A There would be no change in where gas giants could
form, because the freezing point of ices did not affect the
formation of gas giants.
B The gas giants could have formed at a closer distance.
C The gas giants would have to form at a larger distance.

C

Which of the following observations of an extrasolar
planet system would be inconsistent with our theory of planet
formation?
7.A Few or none of the planets have moons.
B Several of the planets rotate in opposite directions to
their orbits around the star.
C There are two terrestrial planets close to the star and
two gas giants further out.
D About half of the planets around a star orbit in one
direction, and half in the other direction.

B

The habitable zone is defined as a region around a star
where ...
8.A terrestrial planets can form.
B oxygen rich atmospheres can form.
C planets could have liquid water on their surface.
D signs of extra-terrestrial life have been detected.

C

Which of these observations would suggest the presence
of a planet orbiting a star?
9.
A the detection of X-ray radiation from the star
B The brightness of a star is slightly different between
two observations.
C A slight decrease in the brightness of a star that repeats
multiple times with regular periods.
D A rapid brightening of the star

-

A "hot jupiter" is a gas giant with similar mass to
jupiter, but ...
10.A ... it is much closer to its star making its atmosphere
much hotter.
B ... it is a very low mass star, rather than a planet.
C ... it has such a hot atmosphere it emits mainly in the
ultraviolet.
D ... it has more greenhouse gasses in its atmosphere.
E ... nuclear fusion is occurring in the core - making the
planet hotter.

A

You are looking for extrasolar planets using the
Doppler technique. What features are most important for
you to measure?
11.A The peak color of the spectrum.
B The brightness of the star.
C The wavelengths of lines in the spectrum.
D Whether there are more emission or absorption lines
in the spectrum.

A (maybe)

What type of extrasolar planet is most easily detected
by the Doppler technique?
12.A Jupiter-mass planets far from their sun.
B Earth-mass planets far from their sun.
C Jupiter-mass planets close to their sun.
D Earth-mass planets close to their sun

C

Why is Venus so much hotter than Earth?
13.A Venus is closer to the Sun.
B Venus rotates more slowly.
C Venus was formed before the Earth was.
D Venus has significant amounts of carbon dioxide in its
atmosphere.
E Venus is more massive.

D

Which of the following shows evidence for ancient river
beds?
14.A Venus.
B Mars.
C the Moon.
D Mercury

B

What is the fundamental reason that Mars has become
virtually geologically dead (unlike the Earth which is geologically
active)?
15.A Its multiple moons.
B The absence of human life on Mars.
C Its red color.
D Its greater distance from the Sun.
E Its relatively small mass.

E

If the polar ice decreases, what would happen, and
why?
16.A Cooling, because melted ice cools things off.
B Cooling, because more sunlight is reflected.
C Warming, because more sunlight is absorbed.
D Warming, because more sunlight is reflected.

D

What kind of thermal radiation does the Earth emit?
17.A infrared light
B visible and ultraviolet light
C visible light
D infrared, visible, and ultraviolet light
E infrared and visible light

A

Why does increasing the amount a greenhouse gas increase
the temperature of a planet?
18.A Greenhouse gases absorb visible light.
B Greenhouse gases absorb infrared light.
C Greenhouse gases emit infrared light.
D Greenhouse gases emit visible light

B

What is the scientific evidence for human contributions
to global climate change?
19.A Humans burn forests, drive cars, and build power
plants that directly heat the planet.
B Humans are responsible for every possible change to
the planet, since humans are the only intelligent life forms.
C Climate models show that extra carbon dioxide contributed
by humans is enough to match the data.
D There is no compelling evidence for human contributions
to climate change; the correlations do not show what
causes them.
E Humans deplete the ozone layer, allowing more ultraviolet
radiation to reach the Earth.

D

Why is Mars so much colder than the Earth?
20.
A Because Mars has a very thin, diffuse atmosphere.
B Because the albedo of Mars is similar to the Earth.
C Because Mars has a little less gravity than the Earth.
D Because Mars is farther from the Sun.

D

Why didn't a planet form where the asteroid belt is
now located?
21.A The temperature in this portion of the solar nebula
was just right to prevent rock from sticking together.
B There was too much rocky material to form a terrestrial
planet, but not enough gaseous material to form a jovian
planet.
C Gravitational tugs from Jupiter prevented material
from collecting together to form a planet.
D There was not enough material in this part of the solar
nebula to form a planet.

C

In what direction does a comet's tail point?
22.A Towards the Earth.
B Towards Polaris, the North Star.
C Away from the Sun.
D Towards the Sun.
E Towards the Moon

C

If impacts that destroy much of life on Earth happen
about once every 100 million (100,000,000) years, and your
typical human life span is about 100 years, what are your
chances of dying from an impact?
23.A One in a hundred (100).
B One in 10 trillion (10,000,000,000)
C One in a billion (1,000,000,000).
D One in a million (1,000,000).
E One in a trillion (1,000,000,000)

D

How does a major impact in one spot on Earth affect
the climate of the entire Earth?
24.A It sends debris into the Earth's atmosphere that
blocks sunlight, making the Earth's surface cooler.
B The impact tears a hole in the Earth's atmosphere,
allowing heat energy to escape.
C The hole that the impact creates leads to a massive
release of greenhouse gases.
D The giant crater created by the impact fills up with
water, which increases the quantity of greenhouse gases in
the atmosphere.
E Since we haven't lived through a major impact, we do
not know.

-

Why isn't Pluto considered a major planet anymore?
25.
A Because it doesn't have any moons.
B Because it is too far away from the Sun to count as a
planet.
C Because it is one of many small icy rocky dwarf planets
in the outer solar system.
D Because it was caught dating Jupiter's girlfriend.

-

Order the interior layers of the Sun from the hottest
to the coldest.
26.A core, radiation zone, convection zone, photosphere
B photosphere, convection zone, radiation zone, core
C radiation zone, core, convection zone, photosphere
D photosphere, convection zone, core, radiation zone

A

Why isn't the Sun shrinking or expanding?
27.
A Because the Sun has lived for billions of years.
B Because gas pressure balances gravity in the Sun.
C Because the Sun is spinning so fast, the centrifugal
forces keep the surface of the Sun supported against collapse.
D Because the Sun is a solid substance.

B

What is the source of the Sun's energy?
28.
A Diet Coke and Mentos.
B We do not know because we can't travel to the center
of the Sun.
C Chemical energy.
D Nuclear fusion.
E Gravitational potential energy.

D

Which of the following statements is an inference from
a model (rather than an observation)?
29.
A The corona is hotter than the photosphere.
B The Sun's core is gradually turning hydrogen into helium.
C The Sun emits neutrinos.
D The photosphere is made out of mainly hydrogen and
helium.
E The photosphere emits visible light.

B

When the temperature of the Sun's core goes up, what
happens next?
30.
A Fusion reactions slow down, the core expands and
heats.
B Fusion reactions speed up, the core shrinks and cools.
C Fusion reactions slow down, core shrinks and heats.
D Fusion reactions speed up, core expands and cools.

D

How does the fusion of hydrogen into helium produce
the energy that powers the Sun?
31.
A The helium has a little bit less mass than the four
hydrogens that get fused together to make it, and this difference
comes out as energy according to E = mc2
B This has not been figured out yet.
C Because helium is a hotter element, having more hydrogen
than helium raises the temperature of the Sun, providing
the light we see.
D Increasing the amount of helium increases the speed
of light, c, inside of the Sun, and this produces the energy we
see.
E Because helium atoms emit more energetic photons
than hydrogen atoms, so the net result of fusing hydrogen
into helium is more energetic photons

-

How do we know how old the Sun is?
32.
A From Newton's version of Kepler's third law and the
orbits of the planets.
B From calculating its fuel supply and how fast it is using
it up.
C From ages of solar system meteorites, based on radioactive
elements.
D From its speed and distance from us.

C

Which of the following quantities is equal to the energy
per second generated by the Sun's nuclear reactions?
33.
A the force of gravity holding the Sun together
B the luminosity of the Sun's photosphere
C the temperature of the Sun's core
D the temperature at the Sun's photosphere

B

Which of the following properties of a star can be measured
during a single night at the telescope?
34.
A luminosity
B apparent brightness
C distance
D parallax

A

If the distance between us and a star is doubled, with
everything else remaining the same, the luminosity
35.
A is decreased by a factor of four, and the apparent
brightness is decreased by a factor of four.
B remains the same, but the apparent brightness is decreased
by a factor of four.
C is decreased by a factor of two, and the apparent
brightness is decreased by a factor of two.
D remains the same, but the apparent brightness is decreased
by a factor of two.
E is decreased by a factor of four, but the apparent
brightness remains the same.

B

Which main sequence star has has the lowest mass?
36
A G
B M
C A
D O
E Can't tell from information provided.

B

Which star is the hottest star?
37.
A A
B G
C O
D M
E Can't tell from information provided.

C

If a star has a mass of 10 solar masses and a luminosity
of 10,000 solar luminosities, how long is its lifetime? (The
Sun's life time is 10 billion years.)
38.A 100 billion years
B 10 million years
C 100 trillion years
D 1 million years

-

How do we estimate the surface temperature of a star?
39.
A By estimating its luminosity.
B By measuring the Doppler shifts of absorption lines in
its chromosphere.
C By estimating its parallax.
D By obtaining its spectrum and classifying the spectral
type.

-

Which star cluster is the youngest star cluster? The
one where the brightest main sequence stars are ...
40.
A O stars
B M stars
C A stars
D B stars
E G stars

A