Across
- 5. fusion The process by which two or more small nuclei fuse to make a bigger nucleus
- 6. A developing planetary body that grows by the accumulation of matter/material
- 7. Collision of asteroids on planets in the early solar system
- 8. system sun, planets, and all the other objects that revolve around the sun
- 9. the earliest stage of a star's life
Down
- 1. A gigantic explosion in which a massive star collapses and throws its outer layers into space
- 2. a cloud of gas and dust in space
- 3. compression A process by which the gravity of an object compresses it, reducing the size and increasing density.
- 4. Disk spinning mass of gas and dust from which stars and planets form