Why are black dwarfs virtually invisible?

1 Answer
Mar 18, 2018

Two reasons...


First Reason

A black dwarf is a white dwarf that has cooled to the point of emitting very little radiation. Add to that its small size (roughly the same size as the Earth) and you have a small object that is only really visible by the gravitational effects it has on nearby objects and the effect of transits.

Second Reason

They don't exist - at least not yet. The expected time for a white dwarf to cool and become a black dwarf is about #10^15# years, whereas the age of the universe is a mere #1.38 xx 10^10# years.