White Dwarfs II

In the far distant future, the universe may be packed with diamonds — the remnants of stars like the Sun. Today, though, there are only a few of them. That’s because it takes a long time to make one.

When a star like the Sun dies, it flings its outer layers into space. That leaves only its hot but dead core — a white dwarf. Such an object is as heavy as a star, but only as big as Earth, which is much smaller than a star.

At first, a white dwarf is quite hot. So even though it’s small, it does produce light. It slowly cools off, though, which makes it dimmer. So over hundreds of billions of years, it will fade from view entirely — forming a black dwarf. But the universe isn’t old enough for even a single black dwarf to have formed.

Along the way, though, other things happen. Most white dwarfs are made mainly of carbon and oxygen. As they cool, the carbon crystallizes — turning to diamond. And the heavier the white dwarf, the faster that happens. For a white dwarf as massive as the one the Sun will form, it takes several billion years. But for heavier stars it can happen in as little as one billion years.

Astronomers have seen white dwarfs that have turned to diamond. But such stars are rare. That’s because they had to form from heavy stars, which are also rare. But as more stars become white dwarfs, the number of crystallized ones will grow — sprinkling more diamonds across the universe.

More about white dwarfs tomorrow.

Script by Damond Benningfield