TonyG

Hi Sal, wondered if you'd spot this thread

wez_sti

Surely if the universe is infact spherical, then if travelling in a straight line long enough we would reach the side? Like if we were trapped in a giant ball, although round, if you travelled in one direction you'd eventually reach the edge?

TonyG

Um, the ball is an analogy. In the analogy, it's only the surface of the sphere that is our universe; we're two dimensional creatures stuck to the surface. Moving through the middle of the sphere would be like us moving through time.

wez_sti

Riiiiight, but we can move on 3 axis..??

Maz

iTrader: (34)

I imagined the universe to be an enclosed sphere with us on the inside . Therefore the notion of reaching the end of the universe completely plausible. However this is not possible according to the theory. Why is this if we are inside a bubble so to speak? I know astronomers have seen the edge of our universe some fifteen billion light years away and just seen a red mist. What is beyond this red mist??

BOB.T

Nah, inside or outside the ball, I still don't get it!

BOB.T

Is it 42?

JTaylor

Maz

iTrader: (34)

So what is in the middle of the sphere??

wez_sti

i think what he is suggesting is the we are within the surface that makes up the sphere, so no matter which way we move 'eventually' we will end up where we started...

although my small brain only see's this surface as 2 dimensions so i dont quite 'get' it....

Maz

iTrader: (34)

Yes but what is in the middle? Surely because the universe is made up of matter therefore it is subject to the laws of physics. this would entail the middle of the sphere is subject to these same laws.

wez_sti

I think for this theory to be possible the centre of the sphere would need to be truly empty, void of any matter at all, other wise the there would be a gravatational pull surely...?

TonyG

That (in the analogy) would be the start of the Universe - in time. The 'inside' of the sphere is what has happened in the past, and 'outside the sphere' is what's happening in the future.
It's a bit like an onion, with each layer representing the whole universe at one moment in time.

wez_sti

But surely, to reach the origin of the big bang, which everything is expanding from, you would just need to go in the opposite direction to what we are all travelling in now, not a 4th dimension..?

TonyG

The 'edge' that you're on about here is the light from the Big Bang. What you have to hink about is that when you look out over huge distances, you're not only looking across distance, but further and further into the past, because the speed of light is not instantaneous. For instance, the Sun is 8.5 minutes ago, Jupiter is about 30ish minutes ago, the nearest star is 4.5 years ago, the Andromeda Galaxy is 2 million yers ago....

TonyG

The Big Bang origin is here where I'm sitting as much as anywhere else in the universe. When it happened, the whole universe was in one place at the same time, a singularity. One bang later, and the universe expands like an inflating balloon (back to the 2-dimensional analogy again). The stars/galaxies/matter is all stuck on the surface of this balloon, and all getting farther and farther apart as time goes on.

We see a 3 dimensional universe, but it's made of many more - we just can't see them, but we can imagine them.

wez_sti

So all the matter and electro magntetic rays expanding from the big bang are moving out in an ever expanding ring shape with the light rays the furthest out and i assume the heavier dense matter towards the center of the ring...

But if you could still travell back in space (not time) to the source of the bang, what would be there?

And once you get past the light from the big bang could there not be another big bang somewhere out there also??

Could two expanding universes collide..?

TonyG

First bit - not quite as it's space that's expanding, and carrying all the universe bits along with it.

You can't travel to the centre of the Big Bang, it's wherever you are sitting now. And here. And 15 billion light years away. You can't get past the light from the Big Bang. If you got to the point 15 billion light years away (assume that you can do it instantaneously), you'd still look in all directions and see the same background glow 15 billion light years from where you are

Last bit - who knows? Just because we haven't seen it happen doesn't mean it can't. It would be interesting to watch though.

wez_sti

I think this is all a bit beyond my comprahention...

I'd of though if you could travel fast enough (admitidly stupidly fast) you would be able to overtake the light from the big bang, no?

are we not expanding away from the source of the bang?

danwrx1980

What I find most interesting is that of all the numerical values associated with the Universe, such as our sun for instance, if its size was increased or decreased by as little as 0.1% I seem to remember, it would be impossible for us to have life on this planet. When you read into it a little more, you find a lot of numerical values like that. Such as the way matter is spread throughout the galaxy. If gravity was something like 0.000001% stronger or weaker there would either be a big 'clump' of matter that would be impossible to support life or it would be spread through the galaxy like soup, in which case again it would be impossible for life to have evolved.
This begs two questions for me;
1, were the values of the universe chosen by some superior being or race of beings? If so, where did they stand when they chose these values? (serious mind ****)

2, are there millions of different universes out there and do we just live in the one where the conditions are right?

Either way, its some serious thinking to be done, and I don't have the time, right now, got to mow my lawn

Mitchy260

The big bang is when it all started though and the universe has expanded from that so you cannot look past the big bang 15billion years ago! I think the furthest they have looked back is 14.2billion years, still 750million years in front of the big bang.

The thing i cant get my head around is what are we expanding into? Are we going to keep on expanding or are we going to reach a limit (Like an elastic band) and come hurtling back into where the big bang originated

wez_sti

definately no. 2. Thats that sorted for ya! Now go cut the grass!

TonyG

You can't outrun light unless you do something exotic (warp space, find a wormhole shortcut, both of which Einstein's theory of Relativity allow)
We are expanding away from the origin of the Big Bang, but only in time. It's not like a normal explosion that you see in any "Arneee/Bruce Willis" film.

wez_sti

Yeah i'm aware of the infinite force to accelerate an infinite mass theory, but was thinking outside of the box

as for the second part, you've just made my brain ache!

TonyG

Was that the Bruce/Arneee comment?

lozgti

What is this big bang expanding into? Nothingness?What is that? It must be infinite.

Can someone draw all this so I can understand it.

wez_sti

haha, na the thought of 'time' exanding

getting the simular 'hamster running round its wheel' feeling i got when reading Hawkins!

My brain finds it hard to cope with anything other than time being a constant straight line...

Mitchy260

Anyway our sun is going to end it for us on earth.

The sun will expand into a red giant and expand to 100 times the size it is now. It will eat up mercury and venus and be so close to earth that it will burn it to a crisp.

Human civilisation will not go on unless we can move to a new star and solar system.

Scary thoughts but its a good 5 billion years away yet! We'll blow ourselves up well before that anyway!

wez_sti

reckon with the advance we have made in just the last few hundred years, a billion years should be long enough for to do pretty much what we like!

Although as you say, we'll no doubt of wiped ourselves out by then!

Mitchy260

Yes but we'd have to move our civilisation to a new star and solar system to go on! We could not remain in our solar system because our sun will die and burn itself out.

You'd have to be lucky enough that the planet was in the safe habitable range of the star, not too close but not too far!

Then how would we get there? Space travel in gigantic ships travelling to another star, even our closest stars at 4-5 light years away would be a mission to reach! Travelling at the speed of light in a space craft i think is impossible and it would still take 4-5yrs to get there. Travelling at normal space craft speed and your looking at hundreds/thousands of years to get to another solar system.

The earth will 1 day be a burnt lifeless rock floating in space, makes you think when you look at the bigger picture are we even important at all.

If we have not killed ourselves by then im sure an asteroid will.