Question

section vocabulary
nebula a large cloud of gas and dust in interstellar space; a region in space where stars are born
solar nebula a rotating cloud of gas and dust from which the sun and planets formed

1. describe what happened to the solar nebula?
2. identify what force pulls the matter in a nebula together?
3. explain how did the gas giant planets form?
4. explain how did the inner, rocky planets form?
5. identify where did most of the gas in the solar nebula end up?
6. list what are the four inner, rocky planets?
7. apply concepts what would happen to a nebula if the pressure inside it was greater than the force of gravity? explain your answer.

Explanation:

1. The solar nebula collapsed under gravity, began to spin faster (conservation of angular momentum), flattened into a disk, and the center became the Sun while planets formed in the disk.
2. Gravity is the force that pulls matter in a nebula together.
3. Gas giant planets formed from the accumulation of gas (mainly hydrogen and helium) around a rocky or icy core in the outer regions of the solar nebula disk.
4. Inner, rocky planets formed from the accretion (sticking together) of dust and small rocky particles in the inner solar nebula disk.
5. Most of the gas in the solar nebula ended up in the Sun.
6. The four inner, rocky planets are Mercury, Venus, Earth, and Mars.
7. If the pressure inside a nebula was greater than the force of gravity, the nebula would expand. Gravity acts to pull matter together, while pressure (e.g., thermal pressure from heated gas) acts to push matter apart. If pressure > gravity, the net effect is expansion.

Answer:

1. It collapsed, spun faster, flattened into a disk, Sun formed at center, planets in disk.
2. Gravity.
3. Gas accumulated around a core in outer disk.
4. Accretion of dust and rocky particles in inner disk.
5. In the Sun.
6. Mercury, Venus, Earth, Mars.
7. The nebula would expand as pressure (pushing) > gravity (pulling).