Timeblog.net

This week, astrophysicists has announced the first prove that Dark Matter exists. Dark Matter is a particle that we haven’t detected und understood yet, but we think that it makes up a lot of our universe…but the first important step has been taken, as proving that such a thing exists is comforting, because we now know that the overall direction of thinking isn’t completely wrong. Although we can’t produce dark matter in any experiment, we can observe the universe, as dark matter has to interact with known matter by gravity. So if we can observe gravitational behavior that would not be possible just by the detectable matter, we can deduce the influence of dark matter.

Picture links to the Chandra X-Ray observatory page

As far as I understand it, a collison of two galaxy clusters was observed with an X-Ray telescope, and the existence of Dark Matter was proven by mapping the gravitational fields. This wouldn’t be so significant if not for the fact that in this collison, the visible matter was removed from the Dark Matter. The non-interacting Dark Matter went right through the collision and the normal matter was at a different place, so they could deduce that Dark Matter was present. The other possibility that was always present in observations when this seperation didn’t occur was that the gravitational force would just need a modification. In this case, a modification of gravitation isn’t able to explain the observed gravtational fields.

Here’s an article by Sean Carroll on CosmicVariance about it, and for those who don’t like reading, there’s an audio segment on Science Friday where Sean talks as a guest. He also shortly talks about the much more mysterious Dark Energy.