# Hartle-Hawking Model (How the Universe Can Appear From Nothing)

1. Dec 16, 2009

### TimBowe

Jim Hartle and Stephen Hawking speculated that the universe quantum-fluctuated into existence from nothing.

The Hartle-Hawking idea describes the universe as a giant quantum fluctuation.

2. Dec 16, 2009

### TimBowe

There is nothing outside it. More precisely, there is no outside. There is no creation, it has neither beginning nor end. If the universe has no beginning and no end, we can’t ask why it was created at a particular moment in time because time ceases to exist.

Last edited: Dec 16, 2009
3. Dec 16, 2009

### arunma

It's an interesting theory, and I think it has merit (I'd be interested to see how it can be tested). Still, I don't fully understand what we mean when we say that the universe is $t_0$ years old. If the universe has no beginning as you say, then what is the meaning of the reciprocal of the Hubble parameter (times whatever prefactors the model requires)?

4. Dec 16, 2009

### TimBowe

Hawking and Hartle have proposed a method of combining quantum mechanics and general relativity.

5. Dec 17, 2009

### Chronos

Its an interesting idea, and fundamentally untestable. It assumes an a priori condition - quantum phyics as a 'background' which appears inconsistent with the 'nothing' premise.

6. Dec 17, 2009

### TimBowe

Yes, it may not really be created from "nothing".

7. Dec 17, 2009

### S.Vasojevic

This graphics is from WMAP's site. They seem to be pretty sure about universe starting with quantum fluctuation. So, pre-existing 'background', or what?

8. Dec 17, 2009

### TimBowe

Last edited: Dec 17, 2009
9. Dec 17, 2009

### justwondering

This sequence of posts is all very interesting and, once again, shows how little we actually KNOW. If one likes a mystery, this subject sure fits the bill! All of THIS perhaps being just a perturbation about zero is really wild. I don't think that we even have a chance of 'knowing', EVER. Is it a total waste to try, or just that WE can't help ourselves in trying?

10. Dec 18, 2009

### FlyTy

More answers lead to more and more questions. Yay, epic science battle!

Its been theorized that the universe is like a giant rubber band stuck in a cosmic dance. Collapsing only to re-expand.

If only it was as simple as black holes lead to white holes that lead to the creation of parallel universe.

11. Dec 25, 2009

### TimBowe

In the Hartle-Hawking model there is no beyond, no boundary, everything is perfectly self-contained. There proposal makes a number of predictions which are characteristic of our observed universe.

12. Dec 29, 2009

### edpell

I would say time like velocity is a measure between two points.

The time from the universe having an average temperature of 10 billion degree and having an average temperature of 2.7 degree is about 13 billion years. In order to say what did the universe look like 30 billion years before now there would have to be a time and a place 30 billion years distant. If that place does not exist then we can say there was no universe at 30 billion years ago.

13. Jan 8, 2010

### aib

In the universe EVERYTHING happens for a reason, one of the things that I've found to be particularly inconsistent is the old claims back in the Sagan days, that there was nothing prior to the universe, and then "bang" - some event, caused by nothing. In the current model the universe is expanding, so it also must be expanding into some medium. Sorry well established mainstream science, but I don't see the current model working. It is either there was something prior to the universe and something outside of it - that would make the current *finite with a starting point* model work, if there is a larger than the universe scale structure we cannot observe, or it is the universe had no beginning, will have no end, and is truly infinite.

14. Jan 8, 2010

### TimBowe

The universe can have no beginning, no end, and be finite and unbounded.

15. Jan 8, 2010

### justwondering

"In the universe EVERYTHING happens for a reason"

True, and those 'reasons' may ALL be just pure chance! Perhaps it makes a neater picture/concept if there were nothing before the Big Bang. Nothing like a fresh start you know.

16. Jan 9, 2010