Black dwarf facts for kids
A black dwarf is a type of star that has cooled down a lot. It starts as a white dwarf star. When a white dwarf gets super cold, it stops giving off much heat and light. Then, it becomes very dark, almost black. Scientists aren't sure if black dwarfs actually exist yet. This is because it takes an incredibly long time for a white dwarf to become one. It takes much longer than the current age of the universe, which is about 13.8 billion years.
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How Stars Become Black Dwarfs
Stars like our Sun don't live forever. They go through different stages.
From Star to White Dwarf
A white dwarf forms from a medium or small-sized star. This includes any star less than about nine or ten times the size of our Sun. When these stars use up all their fuel, they can't make energy anymore. What's left is a very dense ball of gases. This dense ball is called a white dwarf.
From White Dwarf to Black Dwarf
After a star becomes a white dwarf, it slowly starts to cool down. It keeps getting colder and colder over a very long time. Eventually, it would stop giving off light and heat. At this point, it would become a black dwarf. Scientists are not sure exactly how long this cooling process takes. Some think it could take 1,000,000 billion years or even longer! Because the universe is only 13.8 billion years old, scientists believe that no black dwarf stars exist yet. They simply haven't had enough time to form.
The Future of Our Sun
Our own Sun will also change over time. In about 8 billion years, the Sun will use up its fuel. It will then become a white dwarf. After many more billions of years, it will continue to cool down. It will stop making light and heat. Eventually, it would become so dark that we wouldn't be able to see it. At that point, it would become a black dwarf.
