Question: What is black mater?

Hayley Evers-King answered on 21 Mar 2013:

Black matter or dark matter is something that scientists think has to exist in the universe. The reason they think this is that there doesn’t seem to be enough mass that we can see to account for the behaviour of the universe – e.g. how things respond to gravity. We can’t see it because it doesn’t emit or absorb light. It”s very mysterious and there’s still a lot of research to be done to figure out exactly what it is and what it does. Great question 🙂