Wheres the big bang point?

Nikolai · Post by **Nikolai** » Thu Aug 21, 2008 12:26 pm

Inflation is a short period of very rapid expansion just after the Big Bang

This is science, not philosophy of science. The philosopher should be above all this

John W. Kelly · Post by **John W. Kelly** » Thu Aug 21, 2008 4:47 pm

Richard Baron wrote: Inflation is a short period of very rapid expansion just after the Big Bang. There are however theories around to the effect that inflation can go on at other times.

It sounds to me as though inflation is faster than expansion.

John W. Kelly · Post by **John W. Kelly** » Thu Aug 21, 2008 4:53 pm

Nikolai wrote:
Inflation is a short period of very rapid expansion just after the Big Bang
This is science, not philosophy of science. The philosopher should be above all this

I would argue that what happens after the BB is indeed science and what happened before the BB is philosophy.

Arising_uk · Post by **Arising_uk** » Tue Sep 02, 2008 8:30 pm

Hi Folks,
I posted the thought because I've been thinking about Bostoms argument in the Bacteria and Mars thread. Whilst thinking about time and Evolution of and within the Universe it dawned on me that the Big Bang and Galaxies velocities, i.e. we're pretty sure they are all 'rushing away' from us in all directions, should mean that they are all rushing away from a point. So I hoped that the more physical amongst us would be able to tell me if we have found the point they are all rushing away from? If not why?
a_uk

RachelAnn · Post by **RachelAnn** » Wed Sep 03, 2008 12:16 am

Q. "If you could have been born in any era, which one would it be?"
A. "The Big Bang."

S G R · Post by **S G R** » Thu Sep 04, 2008 9:11 pm

A_uk

The example normally given to explain how expansion from the Big Bang works is to consider our three dimensions reduced to two and made into a balloon, as the balloon is blown up everything on its surface moves apart. The fascinating thing about this analogy is that there is a point where everything is expanding away from, it is the centre of the balloon but this point is in another dimension to our two dimensional universe . This extra dimension is time!

Arising_uk · Post by **Arising_uk** » Thu Sep 04, 2008 11:16 pm

SGR,
I thought the 'balloon' would appear(as I'd just thought of it as well

).
Whilst I get the analogy with respect to this thing called 'spacetime' and the increasing 'distance' between Galaxies. Would we still not have an 'arrow' of 'direction as they are 'moving' from some central point if the BB is correct? If they are 'moving' in all directions then the BB is wrong?
a_uk

Diomedes71 · Post by **Diomedes71** » Fri Sep 05, 2008 7:06 pm

Hi All

Arising_Uk
The problem you are having is a topological one. Hell it's the problem we all have. I think we're not a hundred percent sure on what the topological make up of the universe is. That's off the point.
The reason we believe in the big bang is because of the evidence that supports it which centres around the fact that we are indeed speeding at ever increasing rates away from our neighbouring glaxies. As SGR exellently explained as evidenced by the observable red shift. What hasn't yet been mentioned is that the prdiction of a Big Bang led to conclusion that if it where so then there would be a background temperature to space. This was subsequently found with the background microwave detector. But the background temperature was not to be even otherwise galaxies would never have formed. And upon inspection fluctuactions where observed. These are BIG facts that before we desert our 'not perfect' big bang theory another theory must predict.

On to your 'Centring' question/ problem. From my understanding of the Balloon analogy, also detailed by our learned friend SGR, if you had enough time and speed of course, if you set of in one direction you would return to the same point. Further with the balloon analogy the idea of a centre becomes meaningless like corners on a circle.

I hope you can disern some sense frm all that.

Regards

Diomedes71 · Post by **Diomedes71** » Sun Sep 07, 2008 11:52 am

THE BALLOON ANALOGY
You paint lots of spots on a balloon and as you futher inflate said balloon which ever spot you focus on all the other spots seem to be accelarating away from the spot you are focused on. Focus on a different spot and you the new spot appears to be the new centre of the expansiton.

The problem this is an analogy, and shows a small glimps of an idea of how there could be sense in the universe without an observabel centre.
The limitation of the analogy is because we see in 3D and still cling like the dumb apes we are to the concept of - aahhh but .. the balloon has a centre. There is a place outside of/ beyond the balloon. I can not visualise any model which takes us from the 2D analogy to the 3D, I don't think anybody can, unless you can visualise high dimensional matrix work, may be a hundred people in the world can. But i can see the futility in asking if I lived in a 2D universe and i was on the balloon.... Where is the centre.. I can supend my disbelief/ comon sense notions and apply this to my universe of possibly 9 or more dimensions and say.. OK it means nothing to ask this question.

John W. Kelly · Post by **John W. Kelly** » Sun Sep 07, 2008 5:10 pm

Thanks for a great explaination Diomedes71 and S G R! I've heard the balloon anology many times, but not as clear as you both have shown.

John W. Kelly · Post by **John W. Kelly** » Fri Sep 12, 2008 9:07 pm

S G R wrote: as the balloon is blown up everything on its surface moves apart.

I understand that the galaxy Andromeda is moving closer to the Milky Way. Are we just "catching up" to Andromeda, even though our local group is exanding from other groups?

Diomedes71 · Post by **Diomedes71** » Sat Sep 13, 2008 11:32 am

Hi John

If Andromeda and the Milky Way are approaching each other then neither is 'catching up' with the other. Gravity has merely ensnared the two in mutual attraction which is greater than the rate if expansion of the universe.

An aside, most people only think of the galaxies rushing away from each other in an expanding universe. The actual 'fabric' of space between galaxies is said to be expanding too. Most evidenced by the red shift of light where its wavelength is lengthened over it's journey over the vast distances.

Regards

RachelAnn · Post by **RachelAnn** » Sat Sep 13, 2008 1:58 pm

Fascinating!! Keep writing on science, this is wonderful!

John W. Kelly · Post by **John W. Kelly** » Sat Sep 13, 2008 4:34 pm

Diomedes71 wrote: The actual 'fabric' of space between galaxies is said to be expanding too.

Never thought of it that way!

Diomedes71 · Post by **Diomedes71** » Sat Sep 13, 2008 6:50 pm

Thanks,

A further analogy I use with my son is this.

I throw a blanket on the floor( with lots of wrinkles in it ) and set some marble on it. I explain the blanket is the space the marbles the galaxies. I gentle pull the blanket and stretch it. I explain the blanket is also what emimated from the Big Bang and is the 'play ground that is our universe'. And it makes no sense to ask what is beyond the blanket or what was there before the big bang... Everything was IN the big bang.

Regards