What does dark matter even do?

摘要

WHAT'S the matter with dark matter? Its name, for one thing. Dark matter is so-called because of the idea that it is like being in a room without a light on. But actually, we know the universe is filled with light even with lots of dark matter in it. We see evidence of this very often - directly from the sun during the day and reflecting off the moon at night. On a clear night we can see stars too. With sensitive instruments, we can also detect the cosmic microwave background radiation that pervades all of space-time. The universe isn't like a room without a light on. It is much more like a giant room with billions of lights spread out all over the place. Light goes right through dark matter - it is transparent. So transparent matter or clear matter would be a better name. However, we are in the dark about what exactly dark matter is.