- #1

Shu Sheng

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- Thread starter Shu Sheng
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- #1

Shu Sheng

- #2

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It is one conceivable scenario that the entire mass of the observable universe could in the distant future = trillions of trillions of years - all end up inside one black hole.

That would eventually evaporate as radiation according to Stephan Hawking.

There isn't any reason I know of though, to suppose that the universe in such a state would do anything to halt or reverse the expansion of space.

Space would still exist but other than the black hole it would be devoid of any kind of matter.

A black hole cannot collapse - it already is in a collapsed condition.

That would eventually evaporate as radiation according to Stephan Hawking.

There isn't any reason I know of though, to suppose that the universe in such a state would do anything to halt or reverse the expansion of space.

Space would still exist but other than the black hole it would be devoid of any kind of matter.

A black hole cannot collapse - it already is in a collapsed condition.

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- #3

Drakkith

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No. Black holes are very small objects and the distances in space are extraordinarily large. Compressing all of the mass of the Milky Way into a single black hole would result in a black hole that is a tiny, tiny fraction of the Milky Way in size. In addition, to stop the expansion of the universe we would need more matter/energy to create more gravity that would slow and eventually reverse the expansion. But even including dark matter we don't have enough. The creation of a black hole does not create more gravity, it simply concentrates it. For example, if the Sun were compressed into a black hole, the planets would continue in their orbits as if nothing had happened.

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Chronos

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Shu Sheng

Thanks guys now I have a deeper idea of black holes :)

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it is possible but on opposite condition that the expansion of space-time overtake the growth of black hole means by the entropy of time ,space more and more expand like a sheet losing its thickness which may lead to more growth of black hole and by emerging in one another the whole mass of universe return to big bang singularity

hence the universe collapse,

and new universe begins.............

- #7

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This does not make sense. Can you restate what it is that you are saying?it is possible but on opposite condition that the expansion of space-time overtake the growth of black hole means by the entropy of time ,space more and more expand like a sheet losing its thickness which may lead to more growth of black hole and by emerging in one another the whole mass of universe return to big bang singularity

hence the universe collapse,

and new universe begins.............

- #8

DaveC426913

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How would the expansion of space time lead to the growth of a black hole? Cosmological expansion does not make things larger.it is possible but on opposite condition that the expansion of space-time overtake the growth of black hole means by the entropy of time ,space more and more expand like a sheet losing its thickness which may lead to more growth of black hole and by emerging in one another the whole mass of universe return to big bang singularity

If anything, expansion would actually result in the black hole being starved for fuel.

- #9

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A black hole with a mass of ≈ 8.7×10^{52} kg would have Schwarzschild radius *r*_{S} ≈ 13.7 billion lightyears... According to NASA/WMAP, that is a somewhat reasonable "Mass of the Universe" estimate... Is there a message hidden here, somehow?

The formula is simple:**r**_{S} (in meter) = 2*GM*/*c*^{2}, where *G* is Newton's gravitation constant, *M* is the mass in kg, and *c* the speed of light in m s^{-1}.

According to Hawking, it would be rather cold... 2.3×10^{-29} K...

The formula is simple:

According to Hawking, it would be rather cold... 2.3×10

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- #10

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No, it is not. It is an estimate of the OBSERVABLE universe. The whole universe is unknown in scope but likely at least orders of magnitude larger than the observable universe and possibly infinite.According to NASA/WMAP, that is a somewhat reasonable "Mass of the Universe" estimate ...

- #11

Chronos

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