Micro black holes, millions / billions of years?

  • Thread starter Nitox33
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  • #26
the evaporation time of a black hole is Tev=5120*pi*G2M2/hc4
where G is the Gravitational constant, M is the mass of the black hole and h is planks constant and c is the speed of light.
A black hole with the mass of a small asteroid (radius of 120 meters) of 1011Kg would last 2.7 billion years so there could be many of these dangerous entities around and we wouldn't know until it was nearly upon us. Perhaps the only way to detect these is by occultation of starlight
 
  • #27
wabbit
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But what would be the mechanism to produce such asteroid-mass blackholes 2.7 bn years ago?
 
  • #28
Chronos
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Sub stellar mass black holes could only have been produced during the very universe to the best of our knowledge, hence the name primordial black holes ]PBH]. Not to worry though, there are far more energetic process than the LHC that occur - even in our own atmosphere. If teeny black holes were produced in such a manner, earth [and every other massive body in the universe] would already be chock full of them. Since we do not see otherwise ordinary looking stars [or planets] winking out of existence, it is safe to deduce they do not possess much of a threat.
 
  • #29
Can't high velocity obliquely colliding back holes create a 'mist' of smaller black holes.
 
  • #30
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@Nitox33: Please open a new thread for that question, as it has nothing to do with black holes.

the evaporation time of a black hole is Tev=5120*pi*G2M2/hc4
where G is the Gravitational constant, M is the mass of the black hole and h is planks constant and c is the speed of light.
A black hole with the mass of a small asteroid (radius of 120 meters) of 1011Kg would last 2.7 billion years so there could be many of these dangerous entities around and we wouldn't know until it was nearly upon us. Perhaps the only way to detect these is by occultation of starlight
If they would be frequent, we would see them "colliding" with stars or planets everywhere. The evaporation would also give a notable signal (if close enough), and nothing has been detected so far.
Can't high velocity obliquely colliding back holes create a 'mist' of smaller black holes.
No, it just gives a single larger, fast-spinning black hole.
 
  • #31
Another scenario is black holes created at big bang time that have evaporated down to asteroid size.
 

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