The Earth is currently headed away from the nearest dwarf star and won't start heading back towards it until about the beginning of July. However, there's no danger of a collision any time soon; we've been orbiting it like this for about five billion years. (The nearest dwarf star is, of course, the Sun.)
There are other dwarf stars "headed towards" Earth in the sense that they're getting closer to us, but again, there's no danger of a collision in the foreseeable future; none of them are headed directly towards us, and the distances involved are so large compared to the relative speeds that the Earth will have become uninhabitable long before any of them could get here even if they were headed directly at us.
No. It is estimated that it would take trillions of years for a white dwarf to cool to a black dwarf. The universe is not old enough for that to have happened yet.
Yes, some of the 20 nearest stars are white dwarfs. For example, Sirius B, the companion star to Sirius A, is a white dwarf. Among the 20 brightest stars, Sirius B is the only white dwarf.
NO!!
It is not old enough. It is estimated that it would take trillions of years for a white dwarf to a black dwarf. The universe is only about 13.8 billion years old.
Not necessarily. Blue stars are short-lived compared to other stars, so they can never be very old, but a red dwarf star can be any age.
A few weeks ago, scientists announced that there were probably three times more stars in the universe than they had previously believed. They didn't "discover" any new stars; they came to believe that there were far more tiny, dim brown dwarf and red dwarf stars than they had thought.
None that are known. Earth is the only place in the universe known to have life and it is highly unlikely that any of the dwarf planets in our solar system have any life.
Only one star has any effect on Earth. The sun is the source of the heat and lightwithout which there would be no life on Earth. None of the other stars has any effect.
Only one star has any effect on Earth. The sun is the source of the heat and lightwithout which there would be no life on Earth. None of the other stars has any effect.
We don't think there are any black dwarf stars yet. There hasn't been long enough for them to cool to the "black" stage. When there has been, then presumably some of them will have satellites.
They can be any age. A brown dwarf is a failed star, one that is not massive enough to start nuclear fusion. A brown dwarf may have formed recently, or could be almost as old as the universe itself.
There are no known stars on a collision course with the Sun. The closest star to our solar system, Proxima Centauri, is still over 4 light-years away. Any potential star encounters with the Sun would be on incredibly long timescales.