Pre big bang infinite cold inflation?

[zerozenones]

I was listening to Brian Cox on Intelligence Squared and he somewhat casually mentioned the general acceptance among physicists of a possibly "infinitely long" period of cold inflation predating the big bang and of the "sudden" stop to this inflation as the source of energy for the big bang... I'm just a science aficionado, but I thought I kept abreast of the current theory in that area of physics...but I've never heard of this! I'm retelling it from memory here and might not accurately relay what he explained, but can anyone elaborate on this for me?

 

[phinds]

Brian Cox is a very popular science popularizer but don't take him too seriously. There are several theories about pre-big-bang and they all share one thing in common which is that they all have zero evidence to back them up. In fact, as far as I know they are all unfalsifiable and thus not even science at all. Personally, I'm going with turtles all the way down since it makes just as much sense as any of the others

 

[siddharth23]

There are literally like a gazillion theories as to what happened before and after the big bang, each more intriguing that the previous one. For all you know, there were infinite number of big bangs and big crunches before the one that led to our universe. Big bang is generally considered the start of time and people just take shots in the dark about what existed before it.

 

[Chronos]

An infinite regression of big bangs would be aesthetically objectionable. Imagine having to live the same life over and over and over ...

 

[siddharth23]

An infinite regression of big bangs would be aesthetically objectionable. Imagine having to live the same life over and over and over ...

Not necessary there would have been life. Hawking says that it's strange that the rate at which the universe is expanding is the exact one which is necessary for the sustenance of life. Who knows how many times the Universe had to try to get that.

 

[phinds]

Not necessary there would have been life. Hawking says that it's strange that the rate at which the universe is expanding is the exact one which is necessary for the sustenance of life. Who knows how many times the Universe had to try to get that.

That's just a cop-out explanation. There's no real science behind it. How would you test it? How would you falsify it?

 

[siddharth23]

That's just a cop-out explanation. There's no real science behind it. How would you test it? How would you falsify it?

You're right. There isn't!

 

[nikkkom]

An infinite regression of big bangs would be aesthetically objectionable. Imagine having to live the same life over and over and over ...

First, laws of physics are unlikely to have concept of aesthetics. :)

Second, even if every BB had the same physical laws and parameters (i.e. lasted the same time, the maximum expansion was the same, etc) it does not mean that the exact same galaxies, stars, and planets form every time. Unless we are horribly wrong about quantum mechanics, we know that this is impossible.

 

[Chronos]

In an infinite loop of big bangs, whatever happens, however improbable, will be repeated an infinite number of times.

 

[bapowell]

Actually, it has been shown that primordial inflation cannot be extended arbitrarily far into the past, i.e. there still must be an initial singularity. For those interested, here are a few of the early papers making this claim: http://arxiv.org/abs/gr-qc/9312022 and http://arxiv.org/abs/gr-qc/0110012