black holes in the lab
IamSmooth, Sun Jun 11 2006, 07:59PMHave any physics labs been able to create microscopic black holes in the laboratory?
If so, why would their existance be so fleeting; how come they don't take in surrounding matter and continue to grow?
Re: black holes in the lab
Bjørn, Sun Jun 11 2006, 08:20PM
There have been some reports of possible black hole looking events but you need a very strong imagination to find any evidence.
The size of a laboratory black hole would be so extremely small that gravity would be insignificantly weak in comparison to other forces at play so it probably would make no difference to the behaviour.
Have a look here for one possible reason for small black holes to be short-lived: http://en.wikipedia.org/wiki/Hawking_radiation
Bjørn, Sun Jun 11 2006, 08:20PM
There have been some reports of possible black hole looking events but you need a very strong imagination to find any evidence.
The size of a laboratory black hole would be so extremely small that gravity would be insignificantly weak in comparison to other forces at play so it probably would make no difference to the behaviour.
Have a look here for one possible reason for small black holes to be short-lived: http://en.wikipedia.org/wiki/Hawking_radiation
Re: black holes in the lab
Marko, Sun Jun 11 2006, 08:40PM
Theoretically a black hole (quantum singularity) can consist of ona two pieces of matter crushed together close enough to be unable to escape their own gravity.
Problem is that here, diameter of 'event horizon' becomes an enormous number of times smaller than for example a proton.
You would need to use some enormous force to crush two protons together, break them into even smaller particles and make the goop small enough for a gravity law F = (m1*m2*G)/d^2 to continue work on its own.
If you try this in real world, for example slaming two protons together with particle accelerators
(using all the power on earth, even more if you need) they would bump together and explode in a bunch of lesse subatomic particles before they were even close to making some kind of singularity.
Actually it seems that such a thing can't happen under any conditions in universe.
I don't know (does somebody else?
) how would such a BH affect surrounding matter or if it would do anything at all.
For a black hole you seem to need some 'critical' mass (one decent star) that will collapse under it's own graviti, to the point where it reaches non-dimensional state, 'falling' into itself as a dot that has no dimensions.
Only thing we see is 'event horison' that is just the line where second cosmic speed reaches speed of light and nothing (matter, energy, it's all the same) can't escape the hole.
'hole' itself has no dimensions (a bit mind boggling, I admit), it has no space and time.
We could (maybe) say that it has completly warped out spacetime from the horizon.
If you could fall into hole (and survive cosmical forces of gravity) you would find yourself in incredibly far 'future' where the hole has evaporated because of hawking radiation and space we know is gone.
I guess that would be pretty scary...
omg omg, whataBS.
I hope some more physics-genius person on this forum can help you much more...
Marko, Sun Jun 11 2006, 08:40PM
Theoretically a black hole (quantum singularity) can consist of ona two pieces of matter crushed together close enough to be unable to escape their own gravity.
Problem is that here, diameter of 'event horizon' becomes an enormous number of times smaller than for example a proton.
You would need to use some enormous force to crush two protons together, break them into even smaller particles and make the goop small enough for a gravity law F = (m1*m2*G)/d^2 to continue work on its own.
If you try this in real world, for example slaming two protons together with particle accelerators
(using all the power on earth, even more if you need) they would bump together and explode in a bunch of lesse subatomic particles before they were even close to making some kind of singularity.
Actually it seems that such a thing can't happen under any conditions in universe.
I don't know (does somebody else?
) how would such a BH affect surrounding matter or if it would do anything at all. For a black hole you seem to need some 'critical' mass (one decent star) that will collapse under it's own graviti, to the point where it reaches non-dimensional state, 'falling' into itself as a dot that has no dimensions.
Only thing we see is 'event horison' that is just the line where second cosmic speed reaches speed of light and nothing (matter, energy, it's all the same) can't escape the hole.
'hole' itself has no dimensions (a bit mind boggling, I admit), it has no space and time.
We could (maybe) say that it has completly warped out spacetime from the horizon.
If you could fall into hole (and survive cosmical forces of gravity) you would find yourself in incredibly far 'future' where the hole has evaporated because of hawking radiation and space we know is gone.
I guess that would be pretty scary...
omg omg, whataBS.
I hope some more physics-genius person on this forum can help you much more...
Re: black holes in the lab
Cesiumsponge, Sun Jun 11 2006, 10:59PM
A miniature black hole with the mass of say...several atomic nuclei...will have the exact gravitational pull as several atomic nuclei (not very much at all). It would not really grow unless you force fed it mass because it simply would not have enough gravitational attraction to capture it's own "food". Even random encounters with other gas molecules (for example) in an open environment might be considered extremely rare because atoms are mostly empty space, and the Schwarzschild radius of a black hole with the mass of atomic nuclei would be basically infintesmally small.
Black holes do follow the laws of physics as a body and their gravitational pull is dependant on their mass, which is usually a fraction of the star that existed once before (taking into account radiated mass and energy as the star dies). That is why so much of the "black holes in labs will swallow the Earth" outcry from some of the science-phobic public is silly.
To my knowledge, the necessary situations for the formation of natural black holes is pretty much guided by the Chandrasekhar limit. The only difference is black holes exist where their Schwarzschild radius/event horizon exists outside their surface diameter while ordinary objects do not. For example, I believe the Schwarzschild radius for the Earth is something on the order of 9-10mm in size. If the Earth was compacted under this critical radius (and it would subsequently crush itself into a singularity), it's Schwarzschild radius would exist outside it's own spherical size and be classified as a black hole. However through natural cosmic means, the Earth's gravitational forces will never exceed neutron or electron degeneracy limits required for such fantastic corpses.
As well, in the lab, you would need to collapse atomic material past it's electron and neutron degeneracy limits which is a very large amount of energy. I am not sure if calculations are abound on the Internet or journals, but I believe even the 1TeV particle accelerators would be considered toys when talking this type of energy magnitude. We have just started to probe subatomic particles and black holes appear to be far out there in terms of technological means.
A dimentionless thing isn't too difficult to imagine.
-A cube is three dimensions and can be described with three values of length, width, and height.
-A square is two dimensional and can be described with two values of length and width.
-A line is one dimensional and can be described with a value of it's length.
-A point has no real dimension as it has neither height, length, or width.
Cesiumsponge, Sun Jun 11 2006, 10:59PM
A miniature black hole with the mass of say...several atomic nuclei...will have the exact gravitational pull as several atomic nuclei (not very much at all). It would not really grow unless you force fed it mass because it simply would not have enough gravitational attraction to capture it's own "food". Even random encounters with other gas molecules (for example) in an open environment might be considered extremely rare because atoms are mostly empty space, and the Schwarzschild radius of a black hole with the mass of atomic nuclei would be basically infintesmally small.
Black holes do follow the laws of physics as a body and their gravitational pull is dependant on their mass, which is usually a fraction of the star that existed once before (taking into account radiated mass and energy as the star dies). That is why so much of the "black holes in labs will swallow the Earth" outcry from some of the science-phobic public is silly.
To my knowledge, the necessary situations for the formation of natural black holes is pretty much guided by the Chandrasekhar limit. The only difference is black holes exist where their Schwarzschild radius/event horizon exists outside their surface diameter while ordinary objects do not. For example, I believe the Schwarzschild radius for the Earth is something on the order of 9-10mm in size. If the Earth was compacted under this critical radius (and it would subsequently crush itself into a singularity), it's Schwarzschild radius would exist outside it's own spherical size and be classified as a black hole. However through natural cosmic means, the Earth's gravitational forces will never exceed neutron or electron degeneracy limits required for such fantastic corpses.
As well, in the lab, you would need to collapse atomic material past it's electron and neutron degeneracy limits which is a very large amount of energy. I am not sure if calculations are abound on the Internet or journals, but I believe even the 1TeV particle accelerators would be considered toys when talking this type of energy magnitude. We have just started to probe subatomic particles and black holes appear to be far out there in terms of technological means.
A dimentionless thing isn't too difficult to imagine.
-A cube is three dimensions and can be described with three values of length, width, and height.
-A square is two dimensional and can be described with two values of length and width.
-A line is one dimensional and can be described with a value of it's length.
-A point has no real dimension as it has neither height, length, or width.
Re: black holes in the lab
Electroholic, Mon Jun 12 2006, 04:00AM
not really, a square is two dimentional. but you only need 1 parameter to describe it, same as a circle, lol.
Just joking.
and hey a sphere is 3d, but you only need 1 parameter!
sorry for being stupid...
Electroholic, Mon Jun 12 2006, 04:00AM
not really, a square is two dimentional. but you only need 1 parameter to describe it, same as a circle, lol.
Just joking.
and hey a sphere is 3d, but you only need 1 parameter!
sorry for being stupid...
Re: black holes in the lab
Carbon_Rod, Mon Jun 12 2006, 04:41AM
Well, if the universe were perceived as a Euclidian 3 space then something would appear as 3 dimensional. However n-vector spaces are not always limited to the same classical dimensional restrictions. There are some that suggest our universe is a hypercube – however we could not be fully aware of such a structure.
There have even been proposals suggesting micro black holes form and collapse all the time – err they may not even be perceivable due to violating traditional space-time causality. However, Hawking’s backward flowing time model suggests a rather interesting contradiction may indeed exist.
In my opinion it’s highly improbable using traditional apparatus of any reasonable scale.
Who knows -- we may finally have a safe place to cleanly dump our garbage.
Cheers,
Carbon_Rod, Mon Jun 12 2006, 04:41AM
Well, if the universe were perceived as a Euclidian 3 space then something would appear as 3 dimensional. However n-vector spaces are not always limited to the same classical dimensional restrictions. There are some that suggest our universe is a hypercube – however we could not be fully aware of such a structure.
There have even been proposals suggesting micro black holes form and collapse all the time – err they may not even be perceivable due to violating traditional space-time causality. However, Hawking’s backward flowing time model suggests a rather interesting contradiction may indeed exist.
In my opinion it’s highly improbable using traditional apparatus of any reasonable scale.
Who knows -- we may finally have a safe place to cleanly dump our garbage.
Cheers,
Re: black holes in the lab
Marko, Mon Jun 12 2006, 08:16AM
Yep, you are right.
Such a hole would need to hit another particle to actually eat it, and since it is incredibly small compared to any part of atom such an event would be pretty unlikely.
Marko, Mon Jun 12 2006, 08:16AM
Even random encounters with other gas molecules (for example) in an open environment might be considered extremely rare because atoms are mostly empty space, and the Schwarzschild radius of a black hole with the mass of atomic nuclei would be basically infintesmally small.
Yep, you are right.
Such a hole would need to hit another particle to actually eat it, and since it is incredibly small compared to any part of atom such an event would be pretty unlikely.
Re: black holes in the lab
Quantum Singularity, Mon Jun 12 2006, 04:58PM
Did someone call me?
I highly doubt that we will see a 'quantum' black hole before seing a regular stellar black hole. On the quantum level - talking about the size of elementary particles - gravity is one of the weakest forces and the nucluer and other forces (repulsion) are much much greater. It would take an enormous amount of power like stated above to force one to happen. Even at that, the closer particles get to each other the stronger the repulsion by the nuclear forces. I have not done any calculations about this but I would guess like said ebove that the Tevetron wouldnt come close.
However, when talking in cosmic terms a black hole is much more possible since over a very long distance gravity is the stongest force. I am not sure if there is any physical proof yet wether or not black holes exist in nature? The last I knew it was highly possible that they were at the center of many galaxies.
Just for clarification: A black hole is a body who's gravitaional pull is so strong that nothing can escape within it event horizon. A singularity is a bit different, and I have heard different ways its explained. But basically it is a point that occupies no space and is infinitely dense. That one is a bit mind boggling. And quantum, like said above, just means on the scale of elementary particles.
Quantum Singularity, Mon Jun 12 2006, 04:58PM
Did someone call me?
I highly doubt that we will see a 'quantum' black hole before seing a regular stellar black hole. On the quantum level - talking about the size of elementary particles - gravity is one of the weakest forces and the nucluer and other forces (repulsion) are much much greater. It would take an enormous amount of power like stated above to force one to happen. Even at that, the closer particles get to each other the stronger the repulsion by the nuclear forces. I have not done any calculations about this but I would guess like said ebove that the Tevetron wouldnt come close.
However, when talking in cosmic terms a black hole is much more possible since over a very long distance gravity is the stongest force. I am not sure if there is any physical proof yet wether or not black holes exist in nature? The last I knew it was highly possible that they were at the center of many galaxies.
Just for clarification: A black hole is a body who's gravitaional pull is so strong that nothing can escape within it event horizon. A singularity is a bit different, and I have heard different ways its explained. But basically it is a point that occupies no space and is infinitely dense. That one is a bit mind boggling. And quantum, like said above, just means on the scale of elementary particles.
Re: black holes in the lab
IamSmooth, Mon Jun 12 2006, 05:08PM
So let's clear something up, and hopefully those with some advanced physics or astrophysics degree will know the answer...
When a star collapses I believed that it's mass was so great that nothing escapes, but it occupies three dimensions. I contrast this with the "singularity."
So, the question is "is it true that a black hole does not have to be a singularity" as alluded to in the previous reply?
IamSmooth, Mon Jun 12 2006, 05:08PM
So let's clear something up, and hopefully those with some advanced physics or astrophysics degree will know the answer...
When a star collapses I believed that it's mass was so great that nothing escapes, but it occupies three dimensions. I contrast this with the "singularity."
So, the question is "is it true that a black hole does not have to be a singularity" as alluded to in the previous reply?
Re: black holes in the lab
Marko, Mon Jun 12 2006, 05:12PM
Black hole occupies no space, and is infinitely dense.
The thing we see as a big black scary thing is generally it's horizon.
A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size. (and you can divide them by size if you wish).
(omg, double post. mod please merge, thanks :) )
[Done but what's wrong with the edit button?]
Again, any BH, 2-proton or galaxy center one both are dimensionless and both have horizons
(Schwarzschild radius-es if you wish).
For a horizon you need high enough gravity that it becomes a point where 2nd cosmic speed exceeds speed of light. (so no matter can escape from that point)
If mass is so great that nothing escapes, BH cannot escape it too and turns into a singularity.
Marko, Mon Jun 12 2006, 05:12PM
Just for clarification: A black hole is a body who's gravitaional pull is so strong that nothing can escape within it event horizon. A singularity is a bit different, and I have heard different ways its explained. But basically it is a point that occupies no space and is infinitely dense. That one is a bit mind boggling. And quantum, like said above, just means on the scale of elematary particles.
Black hole occupies no space, and is infinitely dense.
The thing we see as a big black scary thing is generally it's horizon.
A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size. (and you can divide them by size if you wish).
(omg, double post. mod please merge, thanks :) )
[Done but what's wrong with the edit button?]
So let's clear something up, and hopefully those with some advanced physics or astrophysics degree will know the answer...
When a star collapses I believed that it's mass was so great that nothing escapes, but it occupies three dimensions. I contrast this with the "singularity."
So, the question is "is it true that a black hole does not have to be a singularity" as alluded to in the previous reply?
Again, any BH, 2-proton or galaxy center one both are dimensionless and both have horizons
(Schwarzschild radius-es if you wish).
For a horizon you need high enough gravity that it becomes a point where 2nd cosmic speed exceeds speed of light. (so no matter can escape from that point)
If mass is so great that nothing escapes, BH cannot escape it too and turns into a singularity.
Re: black holes in the lab
IamSmooth, Mon Jun 12 2006, 05:54PM
Does this mean that at the center of every black hole, including the supermassive black holes thought to be at the center of galaxies, is a singularity?
IamSmooth, Mon Jun 12 2006, 05:54PM
Does this mean that at the center of every black hole, including the supermassive black holes thought to be at the center of galaxies, is a singularity?
Re: black holes in the lab
mike0t4ever, Mon Jun 12 2006, 06:06PM
mike0t4ever, Mon Jun 12 2006, 06:06PM
Firkragg wrote ...
....A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size....
uhh and mass....A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size....
Re: black holes in the lab
Marko, Mon Jun 12 2006, 06:25PM
Isn't mass proportional to size (of horizon, of course)?
But yes, that would surely be more appropriate word...
Marko, Mon Jun 12 2006, 06:25PM
uhh and mass
Isn't mass proportional to size (of horizon, of course)?
But yes, that would surely be more appropriate word...
Re: black holes in the lab
Quantum Singularity, Tue Jun 13 2006, 01:18AM
So than a black hole cannot exist without there being a singularity? Said another way, is it then impossible for there to be a 'stable' mass of a certain value and size that has a stong enough magnetic pull to not allow light to escape? Or is it that any object regardless of size or mass that has a gravitational pull that can suck light in must be of infinite density and not occupy any space (other than the apparent space of the event horizon)? I was under the impression that there was another threshold that had to be reached for a black hole to become infinitely dense and form a singularity.
Quantum Singularity, Tue Jun 13 2006, 01:18AM
Firkragg wrote ...
Black hole occupies no space, and is infinitely dense.
The thing we see as a big black scary thing is generally it's horizon.
A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size. (and you can divide them by size if you wish).
Black hole occupies no space, and is infinitely dense.
The thing we see as a big black scary thing is generally it's horizon.
A mini black hole out of 2 protons or one in center of galaxy have no physical differences except size. (and you can divide them by size if you wish).
So than a black hole cannot exist without there being a singularity? Said another way, is it then impossible for there to be a 'stable' mass of a certain value and size that has a stong enough magnetic pull to not allow light to escape? Or is it that any object regardless of size or mass that has a gravitational pull that can suck light in must be of infinite density and not occupy any space (other than the apparent space of the event horizon)? I was under the impression that there was another threshold that had to be reached for a black hole to become infinitely dense and form a singularity.
Re: black holes in the lab
Cesiumsponge, Tue Jun 13 2006, 01:20AM
I think black hole and singularity are used interchangably today By now, I am not sure it matters, but I recall "black hole" was a slang for singularities and describes the Schwarzschild radius of a singularity. Obviously it appears as a "black hole" in the backdrop.
A singularity can never be directly observed as it exists inside it's Schwarzschild radius but as mentioned, you can determine it's mass by measiring the Schwarzschild radius. Also the natural formation of such from dying stars are guided by the Chandrasekhar and Tolman-Oppenheimer-Volkoff limits based on a factor of solar masses.
In order to create a small singularity that fall well below those limits, you need to exceed neutron degeneracy which takes a LOT of energy.
Granted, scientists and physicists sometimes come up with clever ways to cheat and use backdoor methods to accomplish things without breaking the laws of physics so it might be possible. Occasionally you hear articles of teams proposing to create miniature black holes and other exotic research. I'm not sure if any of these have ever come into fruitation though.
Cesiumsponge, Tue Jun 13 2006, 01:20AM
I think black hole and singularity are used interchangably today By now, I am not sure it matters, but I recall "black hole" was a slang for singularities and describes the Schwarzschild radius of a singularity. Obviously it appears as a "black hole" in the backdrop.
A singularity can never be directly observed as it exists inside it's Schwarzschild radius but as mentioned, you can determine it's mass by measiring the Schwarzschild radius. Also the natural formation of such from dying stars are guided by the Chandrasekhar and Tolman-Oppenheimer-Volkoff limits based on a factor of solar masses.
In order to create a small singularity that fall well below those limits, you need to exceed neutron degeneracy which takes a LOT of energy.
Granted, scientists and physicists sometimes come up with clever ways to cheat and use backdoor methods to accomplish things without breaking the laws of physics so it might be possible. Occasionally you hear articles of teams proposing to create miniature black holes and other exotic research. I'm not sure if any of these have ever come into fruitation though.
Re: black holes in the lab
Desmogod, Tue Jun 13 2006, 01:23AM
No, that is not the case, one thing that we try to avoid in physics is infinities.
A black hole still has mass, and it will still emit (hawking) radiation like a hot body, therefore, a black hole isn't truly black.
It will also occupy volume in space.
Desmogod, Tue Jun 13 2006, 01:23AM
Firkragg wrote ...
Black hole occupies no space, and is infinitely dense.
Black hole occupies no space, and is infinitely dense.
No, that is not the case, one thing that we try to avoid in physics is infinities.
A black hole still has mass, and it will still emit (hawking) radiation like a hot body, therefore, a black hole isn't truly black.
It will also occupy volume in space.
Re: black holes in the lab
Simon, Tue Jun 13 2006, 06:26AM
The event horizon of a black hole contains a volume and this is the usual definition of the size of the black hole. Saying that the hunk of matter inside occupies a finite volume is a different thing.
Theoretical physicists who shy away from the idea of infinite density have come up with alternative descriptions of black holes that do not involve singularities.
Simon, Tue Jun 13 2006, 06:26AM
The event horizon of a black hole contains a volume and this is the usual definition of the size of the black hole. Saying that the hunk of matter inside occupies a finite volume is a different thing.
Theoretical physicists who shy away from the idea of infinite density have come up with alternative descriptions of black holes that do not involve singularities.
Re: black holes in the lab
Quantum Singularity, Tue Jun 13 2006, 08:24AM
Don't the laws of physics not apply beyond the boundary of the event horizon of a singularity? In which case you wouldnt have to avoid the infinites because there are no laws that govern whats beyond the event horizon? And I thought by definition that a singularity is a single point in space (point, that means no dimension or volume)?
And I dont beleive anyone said they will not have mass, or infinite mass for that matter, although I could have missed that. They have infinite density because the mass they have takes up no space/volume.
Quantum Singularity, Tue Jun 13 2006, 08:24AM
No, that is not the case, one thing that we try to avoid in physics is infinities.
A black hole still has mass, and it will still emit (hawking) radiation like a hot body, therefore, a black hole isn't truly black.
It will also occupy volume in space.
Don't the laws of physics not apply beyond the boundary of the event horizon of a singularity? In which case you wouldnt have to avoid the infinites because there are no laws that govern whats beyond the event horizon? And I thought by definition that a singularity is a single point in space (point, that means no dimension or volume)?
And I dont beleive anyone said they will not have mass, or infinite mass for that matter, although I could have missed that. They have infinite density because the mass they have takes up no space/volume.
Re: black holes in the lab
Carbon_Rod, Wed Jun 14 2006, 01:27AM
â€Don't the laws of physics not apply beyond the boundary of the event horizon of a singularityâ€
It’s a mystery – there are literally dozens of reasonable hypothesis. Some suggest manifolds in space-time that could not be considered classical mass by any means (infinite or otherwise.)
Most theories today however are not falsifiable by experiment – but a plausible explanation may be observable someday
Personally I think cartoon ACME Inc. holes are less controversial and more logical then some of the ideas.
Cheers,
Carbon_Rod, Wed Jun 14 2006, 01:27AM
â€Don't the laws of physics not apply beyond the boundary of the event horizon of a singularityâ€
It’s a mystery – there are literally dozens of reasonable hypothesis. Some suggest manifolds in space-time that could not be considered classical mass by any means (infinite or otherwise.)
Most theories today however are not falsifiable by experiment – but a plausible explanation may be observable someday
Personally I think cartoon ACME Inc. holes are less controversial and more logical then some of the ideas.
Cheers,
Re: black holes in the lab
Dr. Slack, Wed Jun 14 2006, 11:11AM
Although both are hypothesised and neither has been proved conclusively to exist, black holes and singularities are very different things.
The theory behind black holes is very well supported. A black holes does not need a singularity inside to be black, only sufficient mass. There are places in the universe where a block hole would fit observations well. There are known simple mechanisms by which they could form.
There is no theory behind singularities beyond physicsits saying "so then when nuclear repulsion is overcome and Pauli exclusion is overcome, there's nothing to hold this stuff apart, and it all goes down to ... omg ... nothing". FWIW, I don't believe in singularities, I just don't think we know enough yet about what happens at the extremes of pressure and density (well it helps me sleep at night, other people believe crazier things!) Physicists are starting to come up with theories that avoid infinite density in a singluarity, partly 'cos it's interesting maths, and I suspect partly because they don't believe in infinite density either. Whether such will ever be testable is another matter.
Dr. Slack, Wed Jun 14 2006, 11:11AM
Although both are hypothesised and neither has been proved conclusively to exist, black holes and singularities are very different things.
The theory behind black holes is very well supported. A black holes does not need a singularity inside to be black, only sufficient mass. There are places in the universe where a block hole would fit observations well. There are known simple mechanisms by which they could form.
There is no theory behind singularities beyond physicsits saying "so then when nuclear repulsion is overcome and Pauli exclusion is overcome, there's nothing to hold this stuff apart, and it all goes down to ... omg ... nothing". FWIW, I don't believe in singularities, I just don't think we know enough yet about what happens at the extremes of pressure and density (well it helps me sleep at night, other people believe crazier things!) Physicists are starting to come up with theories that avoid infinite density in a singluarity, partly 'cos it's interesting maths, and I suspect partly because they don't believe in infinite density either. Whether such will ever be testable is another matter.
Re: black holes in the lab
benbradley, Wed Jun 14 2006, 09:29PM
Here's an interesting news story to help answer the OP's question (though these might be closer to "femtoscopic" than merely "microscopic":
Any black hole generated in the lab would be made of only a few particles (in this case a couple of gold atom nuclei), and thus would have an extremely, I say EXTREMELY short lifetime before totally evaporating due to Hawking radiation.
Even if the mass of a mountain were somehow compressed to make a black hole, it would surely evaporate in however long it would take (milliseconds? microseconds? Regardless, I wouldn't want to be on the same planet) rather than take in enough matter to make up for its "evaporation" by Hawking radiation. To double in mass it would have to take in a mountain of material, and even if it's going at high speed it will only take in a very small cross section of matter in its path.
Calculations I made from the formula on this page:
tells me that a one pound (2.2kG) black hole will evaporate in about one nanosecond. The lifetime varies with the cube of the mass, so the lifetime of the alleged black hole in the article would be hugely shorter.
benbradley, Wed Jun 14 2006, 09:29PM
Here's an interesting news story to help answer the OP's question (though these might be closer to "femtoscopic" than merely "microscopic":
Any black hole generated in the lab would be made of only a few particles (in this case a couple of gold atom nuclei), and thus would have an extremely, I say EXTREMELY short lifetime before totally evaporating due to Hawking radiation.
Even if the mass of a mountain were somehow compressed to make a black hole, it would surely evaporate in however long it would take (milliseconds? microseconds? Regardless, I wouldn't want to be on the same planet) rather than take in enough matter to make up for its "evaporation" by Hawking radiation. To double in mass it would have to take in a mountain of material, and even if it's going at high speed it will only take in a very small cross section of matter in its path.
Calculations I made from the formula on this page:
tells me that a one pound (2.2kG) black hole will evaporate in about one nanosecond. The lifetime varies with the cube of the mass, so the lifetime of the alleged black hole in the article would be hugely shorter.
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