This preview shows page 1. Sign up to view the full content.
Unformatted text preview: such as methanol and acetone. Radio telescopes are used to observe these very dark, cold clouds. The clouds are dense relative to the rest of the gas between the stars but are still much less dense than the atmosphere of a planet. Typical cloud densities are 100 to 1000 molecules per cubic centimeter while each cubic centimeter of the air you breath has about 2.5 10 19 molecules---a molecular cloud is tens to hundreds of times &quot;emptier&quot; than the best vacuum chambers we have on Earth! In the parts of a giant molecular cloud where very hot stars (O and B-type) have formed, the hydrogen gas surrounding them can be made to glow in the visible band to make what is called a H II region . The Orion Nebula is an example of this. It is the fuzzy patch you can see in the sword part of the Orion constellation. It is a bubble about 26 light years across that has burst out of one side of the Orion Complex....
View Full Document
This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10