Mini-Black Holes and Stars Winking Out

  • Thread starter RJ Emery
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  • #1
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Isaac Asimov, in his 1979 book A Choice of Catastrosphes: The Disasters That Threaten Our World, raised the possibility that mini-black holes created with the Big Bang may burrow into stars and cause them to wink out (pp. 92-96).

Stephen Hawking in 1974 suggested that (to quote Asimov) "... in the first moments of the formation of the universe, innumerable black holes of all masses from that of a star down to tiny objects of a kilogram or less" were produced. The smaller ones Hawking dubbed "mini-black holes."

I have two questions related to the above:

1) What is the current thinking about mini-black holes, including the creation of black holes of any size or mass with the Big Bang?

2) Has anyone seriously looked for missing stars?

WRT (2), astronomers constantly search for any unusual variation or brightness (e.g., supernova) in any stellar object. Some researchers have also looked for brown dwarfs eclipsing background stars in the Milky Way or the nearby companion galaxies.

However, has anyone actively compared past and current surveys of star fields for missing stars?
 

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  • #2
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can a really small hole be black??
as it needs a lot of mass to trap light
and kilo is not enuff no matter how small and dence
or even a solar mass

can a small BH eat a star?
wouldn't it just pass thru eating some but not a lot of mass
and keep going at about the same speed it came with
unless the BH was really moving slow and is trap in a inside the star orbit

if a BH did eat a star don't we get a light show pluss X-rays
kinda like a mini quasar? and thats hard to miss
 
  • #3
ranger
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can a really small hole be black??
as it needs a lot of mass to trap light
and kilo is not enuff no matter how small and dence
or even a solar mass
It seems the smallest mass needed for a mini BH would be in the order of Planck mass.
http://en.wikipedia.org/wiki/Micro_black_hole
 
  • #4
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can a really small hole be black?? as it needs a lot of mass to trap light and kilo is not enough no matter how small and dense or even a solar mass
No matter how small a singularity may be, it would be black, just on a much smaller scale. Regardless of its initial size, it would grow as it comes into contact with matter. If a mini-black hole existed within our solar system, it would itself not likely be visible but only discernible through its gravitational interactions with the members of the solar system.

Can a small BH eat a star?
Yes, depending on how fast it is moving relative to the star. If it is fast moving and strikes a glancing blow, it probably would not do serious, lasting damage. If it is fast moving and punches through the nuclear center, it could severely disrupt if not extinguish the fusion process there. The star may take some time to recover, during which interval the star's energy output would be substantially reduced.

Wouldn't it just pass through eating some but not a lot of mass and keep going at about the same speed it came with unless the BH was really moving slow and is trap in a inside the star orbit.
If the black hole is slow moving and did become trapped in the nuclear center, then it may well consume the star, and the star would fade out, quite literally here today, gone tomorrow. And it is precisely for that scenario that I wonder if anyone ever checked for missing stars.

If a BH did eat a star don't we get a light show plus X-rays. Kind of like a mini-quasar? and thats hard to miss
The light show occurs with rapidly spinning black holes around which an accretion disk forms. It may be a necessary prerequisite for black holes of any size to be rapidly spinning, but I do not know for sure. If that light show is taking place within a star, it won't be visible. See, for example http://antwrp.gsfc.nasa.gov/apod/ap951226.html" [Broken].
 
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  • #5
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No matter how small a singularity may be, it would be black, just on a much smaller scale. Regardless of its initial size, it would grow as it comes into contact with matter. If a mini-black hole existed within our solar system, it would itself not likely be visible but only discernible through its gravitational interactions with the members of the solar system.


<<HOW!!! a black hole to be black needs enuff mass to be greater then speed of light in its gravity so HOW does a mini hole trap light??
dence is not = to black if mini mass>>>


Yes, depending on how fast it is moving relative to the star. If it is fast moving and strikes a glancing blow, it probably would not do serious, lasting damage. If it is fast moving and punches through the nuclear center, it could severely disrupt if not extinguish the fusion process there. The star may take some time to recover, during which interval the star's energy output would be substantially reduced.

<<as a mini BH is so small and so dence a star even at it's thickest center point
should be like going thru fog or dust in a aircraft and not much drag at all
and ''extinguish the fusion process'' again HOW it goes thru like a knife thru butter soft butter>>


If the black hole is slow moving and did become trapped in the nuclear center, then it may well consume the star, and the star would fade out, quite literally here today, gone tomorrow. And it is precisely for that scenario that I wonder if anyone ever checked for missing stars.

<<a mini hole cannot eat mass very fast
and there is alot of mass in a star
so no not a day or a week or a year
pluss time effects too make it even longer
a small hole grows slow
event horizen is small
as is its gravity>>>


The light show occurs with rapidly spinning black holes around which an accretion disk forms. It may be a necessary prerequisite for black holes of any size to be rapidly spinning, but I do not know for sure. If that light show is taking place within a star, it won't be visible. See, for example http://antwrp.gsfc.nasa.gov/apod/ap951226.html" [Broken].
X rays will get out as will other effects
remember the hole is small and eating slowly
 
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  • #6
Janus
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No matter how small a singularity may be, it would be black, just on a much smaller scale. Regardless of its initial size, it would grow as it comes into contact with matter. If a mini-black hole existed within our solar system, it would itself not likely be visible but only discernible through its gravitational interactions with the members of the solar system.
Not quite. You have to take Hawking radiation into consideration. The smaller the black hole, the greater the output of Hawking radiation and the greater the hole's Hawking Temperature.

For example, a mini-black hole with the mass of 2e19 kg (about the mass of the Saturn satellite Hyperion) would have a Hawking temp of around 6000°K, which is close to the surface temp of the Sun. It would actually glow in the visible light spectrum.
 
  • #7
Chronos
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And Janus pointed out a compelling argument against miniature black holes - there are none in the 'hood'. Hawking has also backed off this prediction by correctly noting the gamma ray background radiation is insufficient to support the existence of such objects in meaningful quantities. BTW, the planck mass black hole eating the earth is a preposterous idea. First of all, it would evaporate almost before it formed, second, its gravitational attractive force would be exactly that of a planck mass - immeasurably insignificant.
 
  • #8
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Chronos how could a planck mass black hole be black
I understand there dought they exist
and may not live long if they do
but how can a small mass be black [not allow light to excape]

and if in a billion to one chance
a black hole was traped inside a star
what would we see happen
mini quasar? x-rays ? nothing?
 
  • #9
"2) Has anyone seriously looked for missing stars?"

Answer:
There a report exists which describes a German star catalog
of the 19th century with hundred thousands of cataloged
stars a n d the missing of more than 70 stars.

Star catalogue: Bonner Durchmusterung, see
Documentation for the Computer Readable Version
W.H. Warren, p. 12, 13, Table 9.
The missing stars are listed by the names of
the catalogue-entry.
 
  • #10
Chronos
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Black holes are misunderstood and ascribed mythological powers in the popular press. The LHC will not cause the demise of earth by producing tiny black holes that sink to the core of the earth and eat it from the inside out. Earth has been bombarded by high energy cosmic rays since it formed. The energy of these particles make LHC energies look like an ice cube in a blast furnace. However many tiny black holes were created by these monumental collisions, earth has not yet been consumed.
 

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