Hi hmcdoc
I presume you would be referring to
the spectral analysis of the light
emitted from a galaxy. Spectroscopy
The light emission spectra of stars
reveal their chemical content. With
this info astronomers are able to
tell the age of the majority of the
detectible stars, and their "lifestyle"
Stars fall on a chart called the
Hertzsprung-Russell (HR) Diagram.
[ http://ast.star.rl.ac.uk/hr.html ]
This diagram lists the characteristics
of the stellar masses based on observations.
Detecting the chemical content and
activity of the stars that comprise
a galaxy, an Astronomer can tell a
great deal of the processes that
brought the galaxy about. Terms such
as new, hot blue stars, and old red
cold stars relate to the info scientists
gather from the star color.
Was this clear? If not, I'd be
glad to re-explain, or elaborate.
-AI |
