1 Apr
2013
1 Apr
'13
2:25 p.m.
Joe, they look at absorption features in the spectrum. That tells them pretty precisely what is in front of what, and what it's made of . On Mon, Apr 1, 2013 at 1:50 PM, Joe Bauman <josephmbauman@yahoo.com> wrote:
I've always wondered how astronomers know the red explosive-looking material is coming from the galaxy and is nothing something in the foreground.