Astronomy
Dark Matter Distribution and Its Influence on Galactic Rotation Curves
Quick fact
In the 1970s, astronomer Vera Rubin discovered that stars at the edges of spiral galaxies orbit just as fast as those near the center—defying Newton's laws unless there is far more mass than we can see.
Why this is interesting
If you could measure how fast stars orbit the center of a galaxy, you'd expect the outer ones to move slower than the inner ones. But they don't. Why?