What information does 21 cm radiation provide about the gas ...

[jerry coleman]

What information does 21 cm radiation provide about the gas clouds?
 
  A) their motion
  B) their distribution
  C) their density
  D) their temperature
  E) all of these

Question 2

What is spectral resolution? Why can a large telescope allow for a higher spectral resolution than a smaller telescope?
 
  What will be an ideal response?

[carolinefletcherr]

Answer to Question 1

E

Answer to Question 2

Spectral resolution is a measure of the amount of detail that can be seen in a spectrum (i.e., how well it can separate out two spectral features from each other). It depends on how widely the light from a telescope is spread out, but the trade-off is that the more the light is spread out, the dimmer it becomes until it becomes undetectable. Since a large telescope gathers more light than a smaller telescope, it can spread the light out further and achieve a higher resolution.

[jerry coleman]

Thanks for the timely response, appreciate it

[kjohnson]

Excellent