To me there's nothing better than gazing up at the stars on a clear night. I often wonder how old they all are. Now astronomers have found a way to accurately measure a star's age.
They do this by looking at how fast a star spins. Like anything set in motion, the longer you leave it, the slower it gets. Stars appear quite featureless from a distance, so to see how fast they spin astronomers had to look for telltale sunspots on their surfaces.