How Can Black Holes Form and Behave in Our Universe?

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Discussion Overview

The discussion revolves around the formation and behavior of black holes in the universe, addressing theoretical concepts, the implications of spacetime deformation, and the effects of cosmic inflation. Participants explore various questions regarding the nature of black holes, Hawking radiation, and the conditions during the Big Bang.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions how black holes can exist given that concentrated matter deforms spacetime and slows time, asking how they can form in finite time from our perspective.
  • Another participant suggests that the distortion of spacetime primarily occurs inside the event horizon, indicating uncertainty about what happens beyond that point.
  • Concerns are raised about whether the expansion of space would prevent black holes from forming, with one participant arguing that it does not hinder the formation of stars or planets.
  • There is a discussion on Hawking radiation, with one participant questioning how black holes can evaporate and suggesting that once below a critical mass, a black hole should gain mass instead.
  • Another participant proposes that Hawking radiation implies micro black holes may not grow, while the effect on larger black holes is minimal.
  • Questions are posed about the Big Bang and whether rapid inflation prevented the universe from collapsing into a black hole, with one participant suggesting that the early universe could be viewed as the opposite of a black hole.
  • Participants discuss the nature of cosmic inflation, with one questioning the speed of expansion during that period and another clarifying that it was greater than the speed of light.

Areas of Agreement / Disagreement

Participants express various viewpoints and uncertainties regarding the formation and behavior of black holes, with no consensus reached on the questions raised. Multiple competing views remain on the implications of cosmic inflation and the nature of Hawking radiation.

Contextual Notes

Some claims rely on assumptions about spacetime and the effects of cosmic inflation, which are not universally agreed upon. The discussion includes unresolved questions about the conditions necessary for black hole formation and the behavior of matter during the early universe.

Tachyonie
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Ok here is a thing I don't understand: How can a black hole exist? There are several things bugging me about black holes:

1) The more concentrated the matter is, the more deformed spacetime is and the slower the time is (from our point of reference). How can Black Hole be created in finite amount of time from our perspective?
2) Shouldnt the expanding of space prevent black hole from being created? Pulling the matter appart just around the borders of black hole creation?

3) Hawking radiation, how can a black hole be evaporated by hawkings radiation? Once the mass lowers under the critical mass needed for black hole it should not undergo the process of radiation and should start gaining the matter back, no?

And something extra:

4) Just want to know, during Big Bang, when all the matter was super concentrated, the super inflation prevented the space from becoming one big black hole by stretching the space so fast that the matter could clump togever?

Thank you for answering my dumb questions. :)
Cheers
 
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The matter, on large scale is uniformly distributed, but this isotropy is broken by the mass of the object, this object create a gravity that contrasts the expansion anti energy.
 
Tachyonie said:
Ok here is a thing I don't understand: How can a black hole exist? There are several things bugging me about black holes:

1) The more concentrated the matter is, the more deformed spacetime is and the slower the time is (from our point of reference). How can Black Hole be created in finite amount of time from our perspective?
It's only really distorted inside the event horizon - what happens inside the event horizon is anyones guess.

2) Shouldnt the expanding of space prevent black hole from being created? Pulling the matter appart just around the borders of black hole creation?
No more than it would stop planets or stars forming.

3) Hawking radiation, how can a black hole be evaporated by hawkings radiation? Once the mass lowers under the critical mass needed for black hole it should not undergo the process of radiation and should start gaining the matter back, no?
Hawking radiation means it may be impossible for micro black holes to grow, the effect on stellar size black holes is very small.

4) Just want to know, during Big Bang, when all the matter was super concentrated, the super inflation prevented the space from becoming one big black hole by stretching the space so fast that the matter could clump togever?
You can regard the initial universe as sort of the opposite of a black hole - this was one of the early models.

Thank you for answering my dumb questions. :)
They're very good questions.
 
Durin inflation the velocity of expanding was c?
 
Ignition said:
Durin inflation the velocity of expanding was c?

No, it was order of magnitude greater.

I can't link in this forum yet, but someone posted a nice link to an explanation of what inflation was.

Just check out "Cosmic inflation" on wikipedia, you should find all the answer you need.

Or there is always the library for more valid info.
 
you can always type out 'www dot awesomewebsite dot com' or something like that if you know a good site and can't yet post URL's.
 

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