Question

What are black dwarfs?

Answer 1

Black dwarfs are the remnants of red and white dwarfs after they have finished fusing hydrogen into helium and cannot produce light in the visible spectrum, appearing black.

Explanation:

For now, black dwarfs are a theory because the Universe is not old enough to host black dwarfs. White and red dwarfs take a TRILLION years to completely fuse hydrogen into helium and die out. A trillion is 10^12 and the Universe is only 1.38x10^9 years old.