The Interstellar Medium
DUST
- blocks light, produces dark nebulae
- reddens light, making stars look redder
- reflects light, making blue reflection nebulae
- polarizes light
GAS
- usual atoms (hydrogen most abundant)
- hot, low density gas filled with clouds
- molecular clouds are cold (10-100 Kelvins) and dense
Magnetic Fields,
Cosmic Rays,
Photons,
More???
What happens in those dark molecular clouds?