<p>I figured I might as well expand my earlier comment into an answer, as I've cobbled together some more information.</p>

<p>You're talking about the <a href="https://en.wikipedia.org/wiki/Cyclic_model" rel="nofollow">cyclic model</a>, which states that the universe goes through cycles of Big Bangs and Big Crunches. We live in the middle of one of those cycles. Albert Einstein was one of the first to investigate it, but his efforts came to nothing.</p>

<p>The theory has been reincarnated, most recently in 2002 by <a href="http://www.space.com/2372-recycled-universe-theory-solve-cosmic-mystery.html" rel="nofollow">Paul Steinhardt and Neil Turok</a>. They propose that the cosmological constant has changed over time, which could make the accelerating expansion of the universe fit into the theory. Another good article on their idea can be found <a href="http://www.nature.com/news/2006/060501/full/news060501-8.html" rel="nofollow">here</a>. Roger Penrose has also come up with a theory - <a href="http://www.ideasroadshow.com/issues/sir-roger-penrose-2013-07-12" rel="nofollow">Conformal Cyclic Cosmology</a> - along similar lines as Einstein's. You can use <a href="https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology" rel="nofollow">this</a> as a starting point for more reading.</p>

<p>A related topic is the <a href="https://en.wikipedia.org/wiki/Big_Bounce" rel="nofollow">Big Bounce</a>, which attempts to address the Big Bangs and Big Crunches.</p>

CC BY-SA 3.0
2015-01-22T05:51:21.197Z
This is all great stuff. Thanks so much for pointing me in the right direction!
MillerMedia
CC BY-SA 3.0
2015-01-14T21:54:34.290Z
2015-01-14T21:54:34.290Z
HDE 226868
<p>I've been reading some of Stephen Hawking's work on the theory of the expansion (and ultimate contraction) of the universe and was curious if anyone has every hypothesized that the universe has possibly gone through this cycle before (or many many times before).</p>

<p>I know it would be impossible to determine because the idea of the universe contracting back to the size it was at the point of the Big Bang (or at the end of a Big Crunch) suggests that all of the laws of physics would break down but has anyone hypothesized and written work on this. I'd be curious to read more about the idea if so.</p>

CC BY-SA 3.0
2015-01-03T13:07:42.690Z
A couple of rather recent articles in *Nature* are relevant: (1) [Clash over the Kardashians of science](http://www.nature.com/nature/journal/v512/n7513/full/512117e.html) and (2) [Scientific method: Defend the integrity of physics](http://www.nature.com/news/scientific-method-defend-the-integrity-of-physics-1.16535).
David Hammen
CC BY-SA 3.0
2015-01-03T14:27:22.217Z
[Yes.](https://en.wikipedia.org/wiki/Cyclic_model) If you're interested in the historic aspects (of, say, Einstein's investigation), feel free to put this on HSM instead. If you're interested in the details of the model, though, Astronomy is a better fit.
HDE 226868
CC BY-SA 3.0
2015-01-03T18:02:43.977Z
@DavidHammen, I understand what you're getting at with those links but I don't see why exploring the idea is a problem? Curiosity, even for a beginner, is not a bad thing. I'm entering through the same door many others have...
MillerMedia
CC BY-SA 3.0
2015-01-04T17:37:05.803Z
I think [this](http://en.wikipedia.org/wiki/Cycles_of_Time) book is related.
Yashbhatt
CC BY-SA 3.0
2015-01-07T08:58:30.903Z
@HDE226868, that link is great, thanks. That's exactly the kind of thing I was looking to read.
MillerMedia
<universe><big-bang-theory><expansion><early-universe>
Big Bang / Big Crunch cycle?
MillerMedia
# Big Bang / Big Crunch cycle?

(Asked by: username_0 on 2015-01-03)

I've been reading some of Stephen Hawking's work on the theory of the expansion (and ultimate contraction) of the universe and was curious if anyone has every hypothesized that the universe has possibly gone through this cycle before (or many many times before).

I know it would be impossible to determine because the idea of the universe contracting back to the size it was at the point of the Big Bang (or at the end of a Big Crunch) suggests that all of the laws of physics would break down but has anyone hypothesized and written work on this. I'd be curious to read more about the idea if so.

**Tags:** universe, big-bang-theory, expansion, early-universe

> **Comments:**
> **username_1**: A couple of rather recent articles in *Nature* are relevant: (1) [Clash over the Kardashians of science](http://www.nature.com/nature/journal/v512/n7513/full/512117e.html) and (2) [Scientific method: Defend the integrity of physics](http://www.nature.com/news/scientific-method-defend-the-integrity-of-physics-1.16535).  
> **username_2**: [Yes.](https://en.wikipedia.org/wiki/Cyclic_model) If you're interested in the historic aspects (of, say, Einstein's investigation), feel free to put this on HSM instead. If you're interested in the details of the model, though, Astronomy is a better fit.  
> **username_0**: @username_1, I understand what you're getting at with those links but I don't see why exploring the idea is a problem? Curiosity, even for a beginner, is not a bad thing. I'm entering through the same door many others have...  
> **username_3**: I think [this](http://en.wikipedia.org/wiki/Cycles_of_Time) book is related.  
> **username_0**: @username_2, that link is great, thanks. That's exactly the kind of thing I was looking to read.  

---

## 1 answers

### Answer by username_2 on 2015-01-14. Score: 3 | Accepted answer

I figured I might as well expand my earlier comment into an answer, as I've cobbled together some more information.

You're talking about the [cyclic model](https://en.wikipedia.org/wiki/Cyclic_model), which states that the universe goes through cycles of Big Bangs and Big Crunches. We live in the middle of one of those cycles. Albert Einstein was one of the first to investigate it, but his efforts came to nothing.

The theory has been reincarnated, most recently in 2002 by [Paul Steinhardt and Neil Turok](http://www.space.com/2372-recycled-universe-theory-solve-cosmic-mystery.html). They propose that the cosmological constant has changed over time, which could make the accelerating expansion of the universe fit into the theory. Another good article on their idea can be found [here](http://www.nature.com/news/2006/060501/full/news060501-8.html). Roger Penrose has also come up with a theory - [Conformal Cyclic Cosmology](http://www.ideasroadshow.com/issues/sir-roger-penrose-2013-07-12) - along similar lines as Einstein's. You can use [this](https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology) as a starting point for more reading.

A related topic is the [Big Bounce](https://en.wikipedia.org/wiki/Big_Bounce), which attempts to address the Big Bangs and Big Crunches.

> **Comments:**
> **username_0**: This is all great stuff. Thanks so much for pointing me in the right direction!  

---

