do scientists really believe in the big bang theory?

if the big bang created the universe which is everything, and it is expanding, then what could is it expanding into?

Build a space ship that can go many, many times the speed of light, travel for a few million years, and you could quite possibly find out.

That is of course if you don't dissapear after you reach the border of expansion.

What I think, that it is nothingness, maybe another demension or something.

Seems to me that there is no possible way of finding out for sure.

Yes, in fact, they DO believe in the Big Bang theory. It fits the current observations and predicitons about what they'd find if things happened as they said so far have matched the theoretical model.

I'm not an astronomer, but the place to ask about BigBang (if you want the hard data and full explainations from astronomers) is the Bad Astronomy forums:

www.badastronomy.com

There's a number of theories on what the universe expands in.

There's a fair branch of string theory that holds weight in the theory of ekpyrosis. Hot damn it's been a while since I thought about this, that may not be the right term. Oh well, it's the theory that collisions between two or more large 3 Dimensional universes existed within a much larger 4-11 dimensional universe, and when they slammed together let off a discharge that was similar to a white hole, or the Big Bang.

It's really, very hard to explain without some nifty 3D graphics, sorry.

There are many theories out trying to explain the birth of our universe and its possible fate. Many are extensions of the superstring theory, like the ekpyrotic theory*, the one Viendin talked about.

Many problems arise with the original big-bang theory, such as horizon, flatness, monopole, etc. However, there has been some modifications of the theory, such as the early/new inflation theories, and the chaotic inflationary theory, that try to provide solutions or explanations to some of the problems stated above.

Due to limited technology, there is no direct way to find out which theory is correct regarding the birth/end of our universe. The only thing the scientists can do is to come up with new theories.

M-theory seems the most promising. Try researching on these, it might help or it might create more questions!

* - About the ekpyrotic theory. This animation from space.com might help visualize what Viendin described.



[edit on 26-9-2004 by jp1111]

Originally posted by Viendin
There's a number of theories on what the universe expands in.

There's a fair branch of string theory that holds weight in the theory of ekpyrosis. Hot damn it's been a while since I thought about this, that may not be the right term. Oh well, it's the theory that collisions between two or more large 3 Dimensional universes existed within a much larger 4-11 dimensional universe, and when they slammed together let off a discharge that was similar to a white hole, or the Big Bang.

It's really, very hard to explain without some nifty 3D graphics, sorry.

Thats the best explaination IMHO. I have spoken with one of the scientists that worked on the hubble project via email. I asked him "exactly how far can the HST veer into our universe. His answer (to the letter) was "There is no limit as to how far the Hubble Space Telescop can see. The only limitations are posed by the univers itself" He went on to say that the reason they so stongly believe in the big bang theory is because with the HST they can see a (still expanding mind you) ring around our entire universe some 13 - 17 or so billion light years out. Hubble can not see past this ring. and so theoretically our universe is still being created inside the ring as it expands. It is believed that some day when this ring around our universe slows down that gravity from all the mass of our universe will start to cause it to collapse back in on itself...... thats basically the way he explained it to me

what I dont understand is....where did all the matter come from?
what exactly exploded to start the big bang and where did all the energy required to do so come from? it had to come from somewhere
this is a very hard thing to comprehend as I am trying to figure this out within the limited mind that we human beings have

From what I understand it was always there. Just in the form of energy. And Theoretically the "Big Bang" was caused by two juxtaposed dimensional planes or membranes (not sure what the scientific name is) were constantly waving and they eventually hit eachother. and when they did all that energiy was released and caused an explosion. That is my understanding of the whole thing.(which is based solely on many late night and re-runs of nova and or origins)

I too would like to know how the big bang occurred. Did it all start
from something as small as an atom, or, was there one huge, gigantic,
gargantuan rock out in space that blew up and started spreading outward?
Whichever occurred, at what speed did it expand outward? It is estimated
OUR universe is approximately 14-16 Billion years old. Well, I tend to
differ from this. We are now able to see out into space almost to the
edge of our universe with the Hubble. The distance we can see stars, is
that 14-16 billion light year distance. Well, I don't believe it is possible the big bang spread out at the speed of light. I believe it spread out at a much slower rate. That would make our universe much, much older. The light
we are witnessing from 14 billion light years away was emitted 14 billion
years ago. If the universe spread out at a tenth of the speed of light, that
would make our universe 10 times older, somewhere in the range of
140-160 billion years old. Again, just because there was a big bang, doesn't mean it all spread out at the speed of light.
One could set off a few pounds of C4 and make a hell of an explosion, but it
sure won't travel at the speed of light.

ZOOMER

Ah, the Big Bang Theory. The entire universe we have today that suddenly began to expand to what it is today from something smaller than the period at the end of this sentence. Doesn't quite make sense to me.

Could the universe possible be spherical? I mean it would take hundreds of millions of years travelling faster than light to find out but I mean theoretically, because the universe can't end, it could just continue to a point one has already been?


What I also dont seem to understand is the theory of expansion. I mean if the universe is of infinite size then how is it expanding, is matter being pulled apart all around us?

Originally posted by fusion360

What I also dont seem to understand is the theory of expansion. I mean if the universe is of infinite size then how is it expanding, is matter being pulled apart all around us?

I am not sure where the newly created mass is coming from exactly. But as for the continued expansion of a supposed already infinite universe....... Well (and this is all theoretical) Our known universe is only a small part of something supposedly infinitely large. See the animation above. If what science tells us is right than our entire universe is in one of those membranes. as for the universe as a whole being infinite well. there could be an infinite number of said membranes. and each could possible have a universe much like our own.... thats how it was explained to me

Originally posted by fusion360
theoretically, because the universe can't end, it could just continue to a point one has already been?

Hmmmmmm? So do you mean like in an old Atari game whereas one could walk off one side of the tv and then come our on the other? I dont think that that is possible because if it were than our universe wouldn't be infinite.

Originally posted by Ignorance Is Bliss


Hmmmmmm? So do you mean like in an old Atari game whereas one could walk off one side of the tv and then come our on the other? I dont think that that is possible because if it were than our universe wouldn't be infinite.

But then this brings us back to expansion theory i also mentionned in the last post. If the universe is infinite, then how is it still expanding? I remember once seeing a picture of a donut shaped universe ((no Homer Simpson joke intended), and that, after hundreds of millions of years, you could return to the same spot you bagan at. Its a theory that could explain the infinite size of the universe and its constant expansion, this might be confusing but im thinking and having problems gettin it out, that while you're moving further away from the point you began, you could also be moving closer once again to it? Ok sounds stupid but we all have a theory.

Well the fact is that there is an infinity of infinities... Some mathematician could explain that better than me, but the fact that the universe is infinite (as we suppose now) doesn't prevent it to grow even further, because there will always be a "bigger" infinity that can enclose the previous one... If I remember it well, the set of infinities is represented by the letter א (aleph) and it is a set comparable to the natural numbers, i.e. it is not continuous, but infinite.

My 2 cents
Big bang = Let there be light.
Science is the best way yet devised for marveling at gods work.

From what I've heard from places, the Big Bang was caused when everything in the universe was being compacted together, and it finally just burst and created a huge explosion, releasing energy.

Also, the universe is currently expanding. But one theory I've heard is that once the universe reaches a "certain point" in size, it will start to contract. It will contract and reduce itself down to nothing, symbolizing the end of the universe, maybe waiting for another Big Bang to happen. This is all theory again.

And yes, most scientists do believe in the Big Bang. The only people that I know who don't believe in it are the huge religious nuts who believe God created everything. I'm not about to get into this huge debate, but the Big Bang does have evidence. Many arguments against it come from the fact that energy cannot be created or destroyed...a simple rule in physics. Now, this rule holds true on Earth, but once you move out into space with particles even smaller than protons and neutrons (I forgot some of their names), this theory become false. I forgot a lot of stuff about this nature, so sorry if it sounds all rushed, but it is the basic theory around the Big Bang.

From what i understand, the universe is as large as there is mass/energy. Outside that there is no universe.But, if an observer were to travel beyond that boundary they would by their existence "stretch they boundary" as the observer would have mass/energy. So what I interpret this as, is that the universe is both finite and infinite in size.

What still confuses me is that there can never be "nothing" in space, particles and anti-particles appear randomly everywhere, its part of quatum mechanics. Which must mean these "virtual" particles expand the universe to infinity. Where there is nothing there must be virtual particles.

On the point of the Big-Bang theory it was meant to have started from a singularity, an infinately small point, which contained everything in the universe and where time started. What this means is that anything that happened before it would have no consequence on what happened after the big-bang, so anything that did happen might as well have not happened!

There are also many string theories on the start of the universe, which are just as viable. The big-bang seems to have the most observational evidence so ill go along with that...for now.

Originally posted by Chieftian Chaos

Many arguments against it come from the fact that energy cannot be created or destroyed...a simple rule in physics. Now, this rule holds true on Earth, but once you move out into space with particles even smaller than protons and neutrons (I forgot some of their names), this theory become false.

I agree, there is a thing called quantum tunneling, where paticles can "borrow" energy. The shorter the time the more energy they can borrow!(Very basic description)
Heres a good link to a brief description of quantum tunneling and other quantum mechnics issues:
www-theory.chem.washington.edu...

Hell, its all pretty weird. I like to just accept that science is not about truth but about which theories at the time,that are most accurately able to predicts observations.

Thats my say

[edit on 15-10-2004 by kutusha]

[edit on 15-10-2004 by kutusha]

[edit on 15-10-2004 by kutusha]

Originally posted by Chieftian Chaos
From what I've heard from places, the Big Bang was caused when everything in the universe was being compacted together, and it finally just burst and created a huge explosion, releasing energy.

Nothing is known, nor can be known, about what occured before the Big Bang. Science breaks down inside a singularity. We know nothing, and as far as is currently know can never know anything, about the state of things at that time.

What you're describing, though, is known as the Big Bounce. It's an idea from String Theory, and is only applicable if they can figure out quantum gravity. String Theory isn't yet advanced enough to deal with this problem, and our technology isn't yet advanced enough to test the few predictions it's made. It only works out if String Theory can get rid of the idea of a singularity.

Also, what explosion? Things aren't flying through the universe, rather the universe itself is getting bigger. To that effect, there is no explosion involved. And questions such as "What happened before the Big Bang?" and "What is our unvierse expanding into?" are best left to philosophers and theologins. They're beyond the realm of science, and a scientific answer should not be sought.

Also, the universe is currently expanding. But one theory I've heard is that once the universe reaches a "certain point" in size, it will start to contract. It will contract and reduce itself down to nothing, symbolizing the end of the universe, maybe waiting for another Big Bang to happen. This is all theory again.

This happens if lambda, the cosmological constant, is 0, and the Big Crunch isn't going to happen. Buy a parka, cause the universe is probably going to go out in a few trillion years due to heat death.

And yes, most scientists do believe in the Big Bang. The only people that I know who don't believe in it are the huge religious nuts who believe God created everything.

Not true. There are reputable wo/men of science who believe in other competing theories. They're in the minority, though.

I'm not about to get into this huge debate, but the Big Bang does have evidence. Many arguments against it come from the fact that energy cannot be created or destroyed...a simple rule in physics. Now, this rule holds true on Earth, but once you move out into space with particles even smaller than protons and neutrons (I forgot some of their names), this theory become false. I forgot a lot of stuff about this nature, so sorry if it sounds all rushed, but it is the basic theory around the Big Bang.

Actually, mass/energy conservation holds for the smallest and largest of things. You just have to take a time average. If a particle "borrows" energy from the universe, it HAS to give it back.

Energy does not have to be conserved at moment of the Big Bang, though, because of the singularity. Physics doesn't hold up, and anything goes. There is no more, and no less, energy in the universe than there was at the time of its creation. It just manifests itself in different ways.