Use these questions to test your understanding. If you get them wrong, you will be linked back to the relevant part of the notes. 

Be sure you study them thoroughly (don't just get a quick fix for your mistake) so your overall understanding is improved.

1. The planets in our solar system are thought to have come from

a. clumps of rocky material that exist between the stars

b. the same cloud of gas and dust in which the Sun formed

c. a cloud of gas in the Orion nebula

d. the Sun (they were flung out of the fast-spinning young sun)

2. As the solar nebula collapsed, it became a disk because

a. the overall rotation of the nebula plus collisions between particles made the particles go in more or less the same direction

b. the initial cloud was disk shaped

c. the Sun's gravity pulled the nebula material into the ecliptic plane

d. the self-gravity of the nebula pulled the material into the ecliptic plane

3. The outer planets are mostly large and gaseous because

a. beyond the frost line, hydrogen froze to form the jovian planets

b. the Sun's gravity caused the denser rock and metals to settle towards the center of the solar system, leaving lighter materials in the outer system

c. beyond the frost line, the gravity of large, ice-rich planetesimals captured the abundant light gases

d. the disk's spin flung lighter materials farther from the Sun

4. Because of the temperatures in the protoplanetary disk,

a. rocks, metals, and ices (hydrogen compounds) froze in the inner region only

b. rocks and metals froze in both the inner and outer regions, and ices froze only in the outer region

c. rocks and metals froze in the inner region only, and ices froze in the outer region only

d. rocks and metals froze in both the inner and outer regions, and ices and H and He gases froze only in the outer region

5. As the solar nebula collapsed under its own gravity,

a. it heated and spun up              b. it cooled and spun up

c. it cooled and spun down              d. it heated and spun down

6. You are sent to find dense and rocky planets. Where in the Solar System should you look?

a. very far from the sun              b. only in the middle

c. close to the sun              d. in circular orbits

e. in regions with lots of moons

7. What kind of experiment has proven most useful for finding planets around other stars?

        a. using a very large telescope to take pictures sensitive enough to capture their light

        b. listening for radio emissions from civilizations on them

        c. measuring the positions of the stars very accurately to detect the effects of the planets' gravity on their motions

        d. measuring accurate Doppler shifts in the stellar spectra to detect the effects of the planets graviational tugs on the stars' motions

        e. using spectrographs to measure absorption features associated with planetary atmospheres

8. A key characteristic of the cloud from which the Solar System formed was its

    a. rotation

    b. color

    c. age

    d. shape

    e. ability to have chemical reactions

9. Planetary systems form

        a. within the dense disks of material surrounding very young stars

        b. when young stars capture smaller bodies that foumed near them

        c. in near-collisions of young stars that pull matter our of them

        d. in eruptions of material from stars settling onto the main sequence

        e. from convection cells in jets from young stars