60-Second Adventures in Astronomy. Number
8: Dark Matter. What's the matter with
dark matter? Fritz Zwicky was a Swiss
astronomer who could probably get you 81
points on a triple word score in
Scrabble. In the 1930s he noticed that
galaxies within clusters were zooming
around far quicker than their mass would
logically dictate, so he figured that
there must be some extra mass in there,
some sort of dark invisible matter
slurping around the universe. He
imaginatively called this dark matter
'dark matter'. But the problem is trying to
prove it, because unlike other dark
things you can see right through this
stuff and this gave Ziggy another idea.
According to Einstein's theory of
general relativity, the more mass
something has, the more it magnifies and
distorts objects that you can see
through it. So by studying the distortion
of distant galaxies, we can calculate
that there must be some extra mass
between us and them, but because we can't
see it touch it or weigh it, is not
surprising that we can't figure out
exactly what it is and that's what the
matter with dark matter is. It makes up
most of the mass in the universe but
when it comes to knowing the details
we're still in the dark.
 
