Question: How do scientists find out new information about dark matter when it's so far away?

Andres Olivares del Campo answered on 6 Nov 2016:

I said that you can find Dark Matter in galaxies far away because, since Dark Matter tends to attract each other (like the Sun attracts the Earth) , there is usually a lot of Dark Matter in places where there is a lot of mass, like in galaxies.

However, there is Dark Matter going through you all the time, even as you are reading this! This Dark Matter could have been in the Sun and suddenly given a push of energy which allows it to reach the Earth, or it could be the result of two other type of particles colliding and creating energy. Either way, the reason why you do not feel all this Dark Matter going through your body is because it interacts very weakly, therefore the chances that you feel something are very very very small!

Now, the way scientist try to learn more about Dark Matter is by building detectors (like the one for neutrinos in my profile) that could observe the interaction of a Dark Matter particle. The way this works is basically, if you imagine two marbles, one small and moving towards the other one, which is big and does not move (this marble is at the detector). When the first marble hits the other one, it would make the second one move a bit in some direction. You can imagine that the small marble is a Dark Matter particle. and the big one is some atom (like Xenon). Then, even though you cannot see the Dark Matter particle directly, you can observe the moment on the second particle in your detector. Even if this happens very rarely, if you have a lot of marbles or if you wait long enough, you could eventually see this happening, and that is what scientist trying to detect Dark Matter are hoping!