Want to slow aging? Gently fuse hydrogen all over your surface

Not to be macabre, but white dwarfs are useful. These are the corpses of stars like the Sun. When stars like this run out of fuel in their cores they blow off their outer layers, exposing the hot, dense core: a white dwarf with the mass of a star packed into a sphere the size of the Earth. The beauty of white dwarfs is that they don’t generate any energy of their own. They’re basically embers, hot balls of glowing matter that cool and fade as they age.

This means they can be used as cosmic cloc...