When the hydrogen used as fuel vanishes, and fusion slows, gravity causes the ... At this stage, the star becomes a large red giant. Because a red giant is so large, its heat spreads out and ...

Starquakes in stars from cluster M67 reveal hidden pauses that mark major internal changes. These pauses improve how we estimate star ages.

When all the hydrogen has been used up in the fusion process, larger nuclei begin to form and the star may expand to become a red giant. When all the nuclear reactions are over, a small star like ...

The galaxy was once nothing but a vast cloud of hydrogen, a little helium and lithium ... The most famous is to puff up to ...