Hi Fraser n Pamela ...

I really love your show ... great format and content.

My question: "When we analyse spectra from a distant object, how can we tell what spectral characteristics can be attributed to the emitting source, and what characteristics are a result of changes to the spectra caused by the emitted photons travelling though a media like a molecular or gas cloud?"

Thank You,
brendan o'brien
outback
Australia

You might want to post this question over on the Science & Technology part of BAUT:

http://www.bautforum.com/space-astro...tions-answers/

This Astronomy Cast forum is pretty quiet most of the time. Neither Fraser or Pamela really post here. If you want to submit a question for the podcast your best bet is to email it to info@astronomycast.com.

But, I think you'll get quicker answers by posting on the main BAUT side of the board.

Rob

will do