Dark Energy, Light, the Universe, and Black Holes

In summary: The universe will keep expanding forever, but the rate of expansion will eventually slow down and reverse, and the galaxies will slowly begin to fall back in.
  • #1
bredmond812
9
0
Hi,

My name is Brandon, I am new here. My physics knowledge mostly comes from surfing the net, so I have a lot of gaps in my understanding. But i do love the stuff, and i try to stay open to it.

Anyway, i know about dark energy and the expansion of the universe. and i guess the expansion of space? the universe? is accelerating and i saw a question somewhere that says that there might be a time where acceleration of the expansion of the universe exceeds the speed of light.

Now I'm just asking, so I am not trying to postulate some new theory to save humanity, but it sounds like the universe has just become a black hole. I say this because the mass of the black hole has stretched spacetime into well, the black hole, so light can't even escape. And then if dark energy stretches space time to where light cannot keep up, isn't that pretty close to the same thing?

thanks in advance.

brandon
 
Space news on Phys.org
  • #3
cristo said:
This page may be a good first reference. I'm moving your post to the cosmology forum.

http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/universe.html

ok, I am sorry for the bad post location. i just didnt know if my conception of the issue was kinnd of borderline, so i put it somewhere where it may be less harmful to the more informed posts.
 
  • #4
The Hubble Volume is the region of space surrounding an observer in which the expansion exceeds the speed of light. The radius of the Hubble Volume is defined as [tex]\frac{c}{H_0}[/tex], where [tex]c[/tex] is the speed of light and [tex]H_0[/tex] is the Hubble Constant.
 
  • #5
it sounds like the universe has just become a black hole. I say this because the mass of the black hole has stretched spacetime into well, the black hole, so light can't even escape. And then if dark energy stretches space time to where light cannot keep up, isn't that pretty close to the same thing?
With accelerating expansion, the universe looks indeed quite like an inside-out Black Hole. Every observer sees an Event Horizon around her (some 25 bn lightyears proper distance away), and sees other galaxies falling toward that horizon, and ulitmately fade away there.
Of course, there's no singularity lurking behind to crunch the infalling (here: outfalling) galaxies in finite proper time.
 

Related to Dark Energy, Light, the Universe, and Black Holes

1. What is dark energy?

Dark energy is a theoretical form of energy that is thought to make up about 70% of the total energy in the universe. It is believed to be responsible for the observed accelerated expansion of the universe.

2. How does light travel through space?

Light travels through space at a constant speed of approximately 299,792,458 meters per second, or about 670,616,629 miles per hour. It travels in the form of electromagnetic waves, which do not require a medium to propagate.

3. What is the universe made of?

The universe is made up of various components, including ordinary matter (atoms and particles), dark matter (an invisible substance that makes up about 27% of the universe), and dark energy (making up about 70% of the universe).

4. How do black holes form?

Black holes are formed from the collapse of massive stars. When a star runs out of fuel and can no longer support itself against its own gravity, it collapses in on itself and forms a black hole. The gravity of a black hole is so strong that not even light can escape from it.

5. Can we see black holes?

We cannot directly see black holes as they do not emit any light. However, we can observe their effects on surrounding matter, such as the distortion of light and the movement of stars, which allows us to infer their presence.

Similar threads

  • Cosmology
Replies
13
Views
2K
Replies
6
Views
1K
Replies
6
Views
969
Replies
7
Views
1K
  • Cosmology
Replies
0
Views
722
Replies
22
Views
1K
Replies
19
Views
1K
Replies
3
Views
1K
Replies
2
Views
968
Back
Top