# Dark Energy, Light, the Universe, and Black Holes

1. Jan 29, 2009

### bredmond812

Hi,

My name is Brandon, Im 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 im 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 blackhole, so light cant even escape. And then if dark energy stretches space time to where light cannot keep up, isnt that pretty close to the same thing?

brandon

2. Jan 29, 2009

### cristo

Staff Emeritus
3. Jan 29, 2009

### bredmond812

ok, im 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. Oct 7, 2010

### Kevin_Axion

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 $$\frac{c}{H_0}$$, where $$c$$ is the speed of light and $$H_0$$ is the Hubble Constant.

5. Oct 8, 2010

### Ich

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.