Question

2/ when we say that the eight official IAU planets have orderly motions, what do we mean?

A/ we mean that they all orbit the Sun in the same big circle, all in a line, one after the other, all revolving counterclockwise

B/ we mean that they orbit the Sun in nearly circular orbits, all going clockwise, all in the same plane

C/ we mean that they orbit the Sun in nearly circular orbits, all going counterclockwise, all in the same plane

D/ we mean that they orbit the Sun in a sphere, all going counterclockwise

5/ where in the solar nebula did rentals condense, in all likelihood?

A/ only outside the frost line

B/ only inside the frost line

C/ it never got cold enough in the solar nebular for metals to condense

D/ everywhere throughout the solar nebula, except very close to the Sun

6/ what, in all likelihood, is the primary reason for the separation of planetary properties (roc/metal-rich vs gas-rich) with distance from the Sun in our Solar System?

A/ scientists can’t explain this observation

B/ the location of the frost line in the Solar Nebula and the types of materials which were able to condense within or outside that line

C/ the location of the bombardment line in the solar nebula and where a planetesimal was located relative to that line

D/ how quickly the solar wind was able to reach the planet to turn off hydrogen and helium gas accretion

7/ Imagine that instead of being between the orbits of Mars and Jupiter, the frost line had instead been located at about Earth’s orbit. What impact might that have had on the number of terrestrial planets in our solar system?

A/ the location of the frost line had nothing to do with the formation of the planet

B/ the number of terrestrial planets would probably have gone down.

C/ there would probably have been no impact

D/ the number of terrestrial would have gone up

8/ why do scientists think did the Jovian planets stop growing?

A/ once a Jovian planet reaches Jupiter’s size, feedback mechanisms in its accretion disk prevent further growth

B/ the solar wind blew the remaining gas away, preventing further growth by accretion gas

C/ they naturally stopped growing once they had accreted all of the gas in the solar nebula

D/ all of the hydrogen compounds and rock/metal condensates beyond the frost line destroyed themselves in collisions, so they could not collide with Jovian planet planetesimals and make them grow

9/ imagine that the solar wind had turned on later in the formation of the solar system than it did. What impact might that have had on the growth of the planets?

A/ planetary formation would have been extended, and planets would have ended up being bigger than they are

B/ planetary formation would have been interrupted and planets would have ended up being smaller than they are

C/ there would have been no impact

13/ 4 planets orbit 4 identical stars. All 4 planets orbit their parent stars at identical average distances. The planets are all terrestrial-type planets, and range in size from small to very large. Which planet would you expect to be the most geologically active?

A/ the rockiest planet

B/ the biggest planet

C/ a planet which is smaller than the biggest planet, but larger than the smallest planet

D/ the smallest planet

14/ Consider what would have happened to a large (~10 times the mass of the Earth) planetesimal if it had formed beyond the orbit of Neptune. If that planetesimal had gone on to form a planet, how would you expect that planet’s mass to compare to the mass of Saturn

A/ larger mass than Saturn

B/ similar to our Sun

C/ smaller mass than Saturn

D/ same as Saturn

15/ which Jovian planet has the biggest internal pressure?

A/ Jupiter

B/ Neptune

C/ Uranus

D/ Saturn

16/ which Jovian planets, if any, have cores which are differentiated into a layer of hydrogen compounds and a layer of rock and metal?

A/ Jupiter

B/ Saturn

C/ Uranus

D/ neptune

E/ all of the above

F/ only Jupiter and Saturn

G/ only Uranus and Neptune

H/ none

17/ why is Io more volcanically active than our moon?

A/ Io is still warm from its formation process

B/ Io is much larger than our moon

C/ Io has a different internal heat source

D/ Io has a higher concentration of radioactive elements

Answer 1

2) The answer to this question is C.

All planets actually move around the sun in elliptical orbits, that are almost circular, and in the same plane. As for the direction, we can say that it is counter clockwise, if we view from the direction of the north pole of the sun.

5) The answer to this question is D.

Frost line is the region outside the solar nebula where volatile elements like ammonia. methane etc condense. The melting point of metals is much higher than such compounds. So, they will condense inside, as well as outside the frost line. So, anywhere, except close to the sun, they will condense.

6) The answer to this question is B.

Different materials start to condense at different distances and they tend to accumulate at those distances over time.

7) The answer to this question is B.

The terrestrial planets are made of solids. Once the frost line is closer, gases will get cooler at this distance, and form jovian planets, thus reducing the no of terrestrial planets.

8) The answer to this question is B

Scientists speculate that after 10 million years of formation, the sun's solar wind cleared away all the gas and dust to outside the solar system.

9) The answer to this question is A

As said in the previous part, the solar wind caused planets to stop growing. A late solar wind means that the planets grow bigger.

13) The answer to this question is B

The geological activity depends on the amount of heat from the sun, stored by the planet. Larger the planet, more energy it holds.

14) The answer to this question is A

A large planetsimal will have high attraction and will attract all the matter in its surroundings. But saturn formed out of itself with no such attraction to collect stars.

15) The answer to this question is A

The internal pressure depends on the mass of the planet. Since Jupiter is the largest, it will have largest internal pressure.

16) The answer to this question is F

Only jupiter and saturn has enough internal pressure to compress the solids into a rock.

17) The answer to this question is C

Lo is a moon of Jupiter. It is volcanicaly active heat form friction generated inside it due to jupiter's gravity.