Week 7, clip 10

Timepoint:  09:33.3

1) What two mechanisms might contribute to star formation in spiral galaxies?  

- Relativistic compression and density waves.
- Supernova shocks and relativistic compression.
- Density waves and supernova shocks.
- None of the above options contribute to star formation.

Answers:
1) Density waves and supernova shocks.