Astronomy Chapter 15 Quiz Q&As

The detection of most extra-solar planets is done by

noting Doppler shifts due to their gravitational influence on their star's motion.

Most of the extrasolar planets found so far were detected by

noting the Doppler shifts of the star as the planet orbits it from side to side.

In terms of its orbit, which of the terrestrials is oddest?

Mercury

How did Mercury's location in the solar system affect its composition?

Mercury is rich in metals because only metallic grains could survive the high temperatures so near the Sun.

Describe two methods that have already been used to study extrasolar planets, and which one gives us the most information. (SA)

Most have been detected by the Doppler shifts they induce in the motion of their home stars, with the periodicity of these shifts telling us their periods. But in the rare cases where the jovian transits its sun, the timing of this light loss gives us the actual masses, sizes, and even densities of the transiting planets.

Which of these is not a consequence of resonance?

Venus' cloud and surface rotation rates

The Kuiper Belt is

a collection of asteroid-sized icy bodies located outside the orbit of Neptune.

Beyond our own solar system, the planets found to date have tended to be

large jovians with orbits more like terrestrial planets.

So far, beyond the solar system the extrasolar planets found have been mostly

large jovians with terrestrial-type orbits.

According to the Solar Nebula theory, planets

should be a common result of star formation.

With rapid collapse from icy planetesimals, what theory would have the jovians growing quickly into giants?

core-accretion

How does the melting and vaporization point of materials determine the composition of the planets?

Durable solids that are very hard to melt and vaporize form close to the Sun, making terrestrial planets.

How did the discovery of Sedna in 2004 fill in a theoretical gap in our knowledge of the outer solar system? (SA)

Sedna is almost as big as Pluto, but much farther out, in fact at the inner edge of the Oort Cloud. So there are large bodes as well as small comet nuclei out in this last frontier of the solar system.

Which statement about extrasolar planets found to date is true?

Some are so close to their stars that their periods are just a few days.

Why did a major planet not form out in the Kuiper Belt?

Some may have, but they have since migrated to orbits nearer the Sun.

What are some of the properties of objects in the solar system that a theory of its origin DOES NOT need to account for? Explain. (SA)

There are many answers to this: Mercury's spin-orbit coupling, Venus' runaway greenhouse effect, the Moon's synchronous rotation, the emergence of life on Earth and its absence on Mars, the Kirkwood gaps in the asteroid belt, and the rings and atmospheric appearance of the outer planets.

Why are the jovian planets so large?

They formed from the largest protoplanets which swept gas from the solar nebula.

Why are the jovian planets so large? (SA)

They were far enough from the Sun that low temperatures allowed most materials to condense out of the nebula, forming planetesimals so large that they attracted and held nebular helium and hydrogen.

What is a distinguishing characteristic of planetesimals which was critical to planetary formation?

They were large enough so that their gravity could attract more material and grow still larger.

The Oort Cloud is believed to be

a spherical cloud of cometary nuclei far beyond the Kuiper Belt.

In comparing our own solar system with others found to date, we find:

a. multiple planets are found in some systems. b. jovians often lie much closer to their suns than ours do. c. that most orbits are less circular than planets around our Sun. d. hot Jupiters, even closer to their stars than Mercury is to our Sun. ALL OF THE ABOVE

Which of the following is not icy in composition?

asteroids

As the terrestrial protoplanets grew in size, their strengthening gravitational fields produced many high-speed collisions between planetesimals and protoplanets which led to what process?

fragmentation

Allowing for more time for the jovians to form, what theory would rely more on gas and less on solid materials?

gravitational instability

The most distant objects in our solar system are

in the Oort Cloud.

A late collision with a large planetesimal may have caused what feature on Mars?

its curious north-south asymmetry

As of early 2010, the number of extrasolar planets found was

over 400, orbiting more than 300 stars.

The concept that Jupiter and the other jovians formed farther out than their present orbits is called

planetary migration.

Objects that are in a 3:2 orbital resonance with Neptune are called

plutinos.

"Catastrophes" are NOT needed to explain

the asteroid belt.

The chief reason the asteroid belt formed is because

the gravitational perturbation of Jupiter disrupting stable orbits there.

In terms of composition

the jovians are much more like the sun than the terrestrials are.