No. This is the hypothetical final stage of a white dwarf, after it cools down so much that it doesn't have a significant amount of energy left. This cooling down takes a long, long time, and white dwarves have not yet have the time to cool down that much (that is to say, the Universe is too young yet to have black dwarves).
Black dwarfs by their name are the opposite of hot. A black dwarf becomes a black dwarf when all residual heat has escaped into space. They will be as cold as space itself. See related question. If this is not an astronomy question but one of "another sexual" nature then I suggest re posting with more precise details in the question.
None of the above. White dwarfs and the black dwarfs they will become consist of a unique state of matter called electron degenerate matter.
I think white dwarfs. This is because they are much more low mass than black holes. White dwarfs are much more common in the universe than black holes, because we have only discovered a few black holes whereas we are aware of many white dwarfs.
According to astronomers and authors Jonathan Weiner and Carl Sagan, white dwarfs - which have been an accepted entities by all astronomers for decades - require an amount of time to "cool down" that well exceeds the current age of the universe - hence there hasn't been enough time for any of them to cool down yet and become "black dwarfs".
There are currently no black dwarfs. The time it would take for a white dwarf to cool to a black dwarf is greater than the current age of the universe.
Black dwarfs by their name are the opposite of hot. A black dwarf becomes a black dwarf when all residual heat has escaped into space. They will be as cold as space itself. See related question. If this is not an astronomy question but one of "another sexual" nature then I suggest re posting with more precise details in the question.
black dwarfs, cuz space is black too, so they would blend in with the night sky. red dwarfs would also be difficult to see, since they are very faint.
No white dwarfs have cooled to become black dwarfs in our galaxy because the universe is not old enough for this process to occur. White dwarfs take longer than the current age of the universe (approximately 13.8 billion years) to cool sufficiently to become black dwarfs, likely requiring hundreds of billions to trillions of years. As a result, all white dwarfs in the Milky Way are still in the cooling phase and none have yet reached the stage of becoming black dwarfs.
None of the above. White dwarfs and the black dwarfs they will become consist of a unique state of matter called electron degenerate matter.
their colour is one thing but a black dwarf originates from a white dwarf
Black dwarfs of black holes.
There are lots of white dwarfs; all the galaxies have them, including ours (the Milky Way).
A sphere.
I think white dwarfs. This is because they are much more low mass than black holes. White dwarfs are much more common in the universe than black holes, because we have only discovered a few black holes whereas we are aware of many white dwarfs.
No black dwarfs are thought to exist. The estimated time it takes for a white dwarf to cool to a black dwarf is greater than the current age of the universe.
According to astronomers and authors Jonathan Weiner and Carl Sagan, white dwarfs - which have been an accepted entities by all astronomers for decades - require an amount of time to "cool down" that well exceeds the current age of the universe - hence there hasn't been enough time for any of them to cool down yet and become "black dwarfs".
There are currently no black dwarfs. The time it would take for a white dwarf to cool to a black dwarf is greater than the current age of the universe.