Exploring the Possibility of Our Universe Being Inside a Black Hole"

In summary, the thread "Dark matter and black holes" mentions that as the mass of a black hole increases, its density decreases. This idea was also mentioned in a book on black holes in the 1970s and is still being explored today. However, research has shown that the universe cannot be inside a black hole due to the absence of a cauchy horizon. This limits the observable volume of the universe but does not necessarily limit the volume that contains matter.
  • #1
Vincent Neave
13
0
I was just reading the thread "Dark matter and black holes" started by Tanzanos and in a reply our PF Mentor, Janus, mentioned that the more mass a black hole has, the less dense it needs to be.

This reminded me of an idea I read in a book on black holes in the 1970s that as the universe contained enough mass and was of sufficient density, there was a possibility that it could actually be inside one!

Well, a lot of matter has passed through the event horizon since then so can anyone tell me if this possibility has been explored further, or if research has uncovered data that has proved it to be impossible?
 
Astronomy news on Phys.org
  • #2
I am in the middle of reading a book "Cosmic Numbers" by James D. Stein. In it he makes the same point, that is the event horizon for the universe, as we know, is much greater than 13.7 billion light years.
 
  • #3
Hi,

Thanks for that, I'd forgotten all about it until the thread I was reading jogged my memory,
nice to know it wasn't just a figment of my aging imagination!
 
  • #4
The book you may be thinking of is The Collapsing Universe by Issac Asimov, where he makes that same point in the last few pages.
 
  • #5
If the universe were a black hole, it should have a cauchy horizon. This is not observed.
 
  • #6
Chronos said:
If the universe were a black hole, it should have a cauchy horizon. This is not observed.

Does that necessarily limit the volume of the universe, at least the volume that contains matter?
 
  • #7
skeptic2 said:
Does that necessarily limit the volume of the universe, at least the volume that contains matter?
Technically not, just the observable portion.
 

1. What is a black hole?

A black hole is a region of space where the gravitational pull is so strong that nothing, including light, can escape from it. This is caused by a large amount of matter being squeezed into a very small space, creating a strong gravitational field.

2. How do we know if we are in a black hole?

Currently, there is no way to definitively know if we are inside a black hole. However, scientists can study the effects of a black hole, such as the distortion of light and the extreme gravitational forces, to make educated guesses about whether we are inside one.

3. Could our entire universe be inside a black hole?

Some scientists have proposed the idea that our universe could be inside a black hole, but this is still a highly debated and speculative theory. There is currently no concrete evidence to support this idea.

4. What would happen if we were in a black hole?

If we were to venture too close to the event horizon (the point of no return) of a black hole, we would experience extreme gravitational forces that would stretch and compress our bodies. Ultimately, we would be torn apart and crushed by the immense gravity.

5. Can black holes be escaped?

Once an object, including light, crosses the event horizon of a black hole, it cannot escape. However, if an object is far enough away from a black hole, it can avoid being pulled in by its gravitational forces. So, in a sense, black holes can be escaped if we maintain a safe distance.

Similar threads

  • Astronomy and Astrophysics
Replies
11
Views
1K
  • Astronomy and Astrophysics
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
5
Views
1K
Replies
3
Views
1K
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
28
Views
5K
  • Astronomy and Astrophysics
Replies
2
Views
1K
Replies
6
Views
1K
  • Special and General Relativity
Replies
5
Views
538
Back
Top