The Big Bang

Sektor31 · Post by **Sektor31** » 2003-01-24 06:04pm

First off, let me state that I'm anti-Creation, and I'm NOT a fundie in any way. I am not trying to imply Intelligent Design.

Good, now we get to the real thing. What do you all think about the Big Bang theory? I have my doubts about it, such as where did the initial material come from?[/b]

Wicked Pilot · Post by **Wicked Pilot** » 2003-01-24 06:10pm

Sektor31 wrote:I have my doubts about it, such as where did the initial material come from?

It always existed

Joe · Post by **Joe** » 2003-01-24 06:12pm

I don't really doubt the big bang, but obviously I have no idea where the initial material came from. I don't even know if science can answer that problem.

Exonerate · Post by **Exonerate** » 2003-01-24 07:05pm

No time, energy, matter, or space before Big Bang. Hence, there is no "before" the Big Bang.

Durandal · Post by **Durandal** » 2003-01-24 07:12pm

The big bang theory is immensely complex and more difficult to grasp than most people think. When most people think of "big bang" they think, "A giant explosion, now I know everything about modern cosmology and I can debunk it with my newly-found understanding." This is how we get creationists. The fact is that cosmologists are not afraid to admit that there are problems with the current incarnations of big bang theory, just not the ones creationists think.

The big bang, however, is an observed fact. The problems come in when cosmologists try and model the mechanisms behind that event. Space is expanding, and if we trace the expansion back, we find that the initial state of the universe was a singularity with characteristics opposite those of a black hole. While a black hole is a singularity that exists throughout all time and no space, the initial singularity of the universe existed throughout all space and no time.

Trying to understand the universe in terms of "where did it come from" won't get you anywhere, because that question relies on a cause-and-effect chain, which is a temporal idea. Since time did not exist in the initial singularity, any reactions which took place would have been literally instantaneous.

Currently, a popular theory of what came "before" the big bang is an inflationary universe, in which all energy existed as vacuum energy, and then the universe became radiation-dominated, then matter-dominated as it cooled. Inflationary cosmology predicts small temperature variation in the cosmic microwave background, which is what we observe, so it's at least somewhat accurate.

The Dark · Post by **The Dark** » 2003-01-24 09:11pm

I thought I read in one of Hawking's books that current physics breaks down within some really small (but measurable) amount of time after the Big Bang (1e-19 second?). Anyone know anything about this (Durandal specifically, since you seem to be the most knowledgable about astrophysics)?

Illuminatus Primus · Post by **Illuminatus Primus** » 2003-01-24 09:30pm

They only basically try and trace it back to within Plank time. You can't work with measurements smaller than that.

GrandMasterTerwynn · Post by **GrandMasterTerwynn** » 2003-01-25 01:00am

Sektor31 wrote:First off, let me state that I'm anti-Creation, and I'm NOT a fundie in any way. I am not trying to imply Intelligent Design.

Good, now we get to the real thing. What do you all think about the Big Bang theory? I have my doubts about it, such as where did the initial material come from?[/b]

Well, the quickest answer is "It was there at the beginning." The Big Bang is the beginning of the universe. When it happened, that's when time started. So, any questions about where it all came from before are absoluely pointless for temporal creatures such as us. The universe simply didn't exist before the big bang.

Now, if you want to get really theoretical, scientists have theorized about the entire multiverse being comprised of a sort of quantum foam. Occasionally you get a random burst of multi-burst energy that makes one of the little bubbles in the foam expand to be a big bubble (big bang -> universe).

Baron Mordo · Post by **Baron Mordo** » 2003-01-25 01:23am

I never understood that part about the universe expanding to a certain point where it would start contracting and then time would go backward. Anyone have the explanation? In l33t if possible.

Durandal · Post by **Durandal** » 2003-01-25 01:43am

The Dark wrote:I thought I read in one of Hawking's books that current physics breaks down within some really small (but measurable) amount of time after the Big Bang (1e-19 second?). Anyone know anything about this (Durandal specifically, since you seem to be the most knowledgable about astrophysics)?

That would be Planck time, which is about 10^-43 s. Any action which takes place in this timeframe is unobservable, and it is part of the mechanism by which black holes decay. You see, within Planck time, virtual particle/anti-particle pairs are spontaneously created all the time. They pop into existence and then annihilate each other, all within 10^-43 s. Basically, Planck time is the equivalent of quantizing time. As light is transmitted in discrete units called photons, time is "transmitted" in discrete units of 10^-43 s. However, we have an extraordinarily poor understanding of time at this point.

I believe that we will, one day, be able to understand the mechanisms behind the big bang, even though there was no time to describe them. While we may not be able to produce a good conceptual model of what happened, the new mathematics being developed that are used in string theory are definitely a start to understanding dimensions beyond our perceptions. Science hasn't let us down yet, folks. We've shown that, with enough time, effort and research, we can understand phenomena which were previously baffling to us.

Baron Mordo wrote:I never understood that part about the universe expanding to a certain point where it would start contracting and then time would go backward. Anyone have the explanation? In l33t if possible.

Well, cosmologists are pretty sure that the universe won't contract, but its expansion will keep accelerating. If the universe did indeed contract, then time would begin going backward. To understand this, you have to realize the difference between two objects simply moving away from each other and the space between them increasing. When cosmologists talk about the universe's expansion, they mean that space is being stretched out. Space and time are intrinsically connected. You might have heard that astronauts in orbit actually come back younger than they should, like if we sent a twin into orbit while leaving his twin brother on Earth, the twin who was in orbit would actually come back slightly younger than his twin, depending on how long he stayed up there. Since gravity is the curvature of spacetime, where greater gravity causes greater curvature, it's simple to infer that greater spacetime curvature will cause time to move more quickly, while a lesser curvature will cause it to pass more slowly.

Cosmologists also have determined that the entire spacetime of the universe, on very large scales, is flat. In other words, all the gravitational pulls of everything in the universe have a net effect of cancelling out. Now, imagine that you are one object, and you're walking toward another object which is receding from you because of the expansion of space. Now, you start walking toward it at a rate equivalent to the rate which you are being separated from it. You remain relatively stationary with respect to that object. Now, imagine that the space between you and the object begins to contract while you are stationary. You are now being pulled toward that object, which has the effect of basically traveling back in time to points where you and that object were closer together.

Another way to look at it is like this. Space and time are irrevocably connected. What affects one affects the other, and what one does, the other does. If space contracts, so does time.

Post by **Darth Wong** » 2003-01-25 01:53am

It should also be noted that the alternate approach being peddled by many (the Bible) has not only failed to explain the mechanisms behind the Big Bang, but also fails to explain pretty much 100% of astrophysics. In fact, you would be hard-pressed to design a working toilet with the knowledge stored in the Bible.

Arrow · Post by **Arrow** » 2003-01-25 09:04am

Ok, here's one thing that confuses me. I keep hearing that space-time is flat. while at the same time I keep hearing that space-time is sitting the wall of a much greater dimension (which only gravity can penetrate) that is spherical or saddle shaped (with the latter offering an explanation for dark matter - an objects gravity gets counted multiple times since gravity can travel through this extra dimension while nothing else in space-time can). So, are these two conflicting ideas or two different things?

SyntaxVorlon · Post by **SyntaxVorlon** » 2003-01-25 11:25am

There are numerous big bang theories, unlike what creationists believe is one big group of non-believers.
One(early big bang theory) supposes that the entire univers was originally packed into one very dense very tiny black hole which for some reason decided to expand. While others think that the universe before was nothing, no time, no space, no reality. And these days there are those who believe that the universe is cyclic, bang, crunch, bang, crunch, and all quite big. And still others are into the idea of numerous universes "stacked" on top of eachother as different d-planes, one may visualize this as a stack of paper that you are seeing through another dimension, each sheet being a universe.

Arrow · Post by **Arrow** » 2003-01-25 11:46am

I've heard of the stack theory before, both in relation to spheric and saddle shape geometry, as it is a possible explaination of dark matter. However, I don't understand the 'flat' space-time geometry and how it relates to the spherical or saddle shaped geometry the the extra dimension that space-time is simply a 'wall' of.

SyntaxVorlon · Post by **SyntaxVorlon** » 2003-01-25 12:16pm

It's hard to understand, I don't fully understand it myself. The idea of space time being flat or curved is a debate between Einstein and Classical Physics, though I remember a while ago that the flat idea was proved by a science satellite's x-ray photos. I might look this stuff up again.

Durandal · Post by **Durandal** » 2003-01-25 05:08pm

Arrow Mk84 wrote:Ok, here's one thing that confuses me. I keep hearing that space-time is flat. while at the same time I keep hearing that space-time is sitting the wall of a much greater dimension (which only gravity can penetrate) that is spherical or saddle shaped (with the latter offering an explanation for dark matter - an objects gravity gets counted multiple times since gravity can travel through this extra dimension while nothing else in space-time can). So, are these two conflicting ideas or two different things?

Spacetime means our three, observable spatial dimensions plus one temporal dimension. It sounds like you're talking about Euclydian space resting on non-Euclydian space (hyperbolic geometry), but that is probably an idea that comes out of string theory, which is untestable currently. I wouldn't worry too much about it until we get a working fusion reactor.

Oh, interesting fact of the day. In hyperbolic geometry, the angles in a triangle add up to more than 180 degrees.

HemlockGrey · Post by **HemlockGrey** » 2003-01-25 05:19pm

Oh, interesting fact of the day. In hyperbolic geometry, the angles in a triangle add up to more than 180 degrees.

How very non-Euclidean.

Aaagh! You've unleashed Cthulhu!

Arrow · Post by **Arrow** » 2003-01-25 05:50pm

Durandal wrote: It sounds like you're talking about Euclydian space resting on non-Euclydian space (hyperbolic geometry), but that is probably an idea that comes out of string theory, which is untestable currently.

Yup, that what I was talking about.

neoolong · Post by **neoolong** » 2003-01-25 06:10pm

HemlockGrey wrote:
Oh, interesting fact of the day. In hyperbolic geometry, the angles in a triangle add up to more than 180 degrees.
How very non-Euclidean.

Aaagh! You've unleashed Cthulhu!

Yup, using non-Euclidean geometry I was able to make a equilateral triangle with three right angles.

Lord Edam · Post by **Lord Edam** » 2003-01-25 06:50pm

Durandal wrote: The big bang, however, is an observed fact.

"and god said 'fuck that was bright' and was blinded for all eternity"

VF5SS · Post by **VF5SS** » 2003-01-25 07:49pm

Lord Edam wrote:
Durandal wrote: The big bang, however, is an observed fact.
"and god said 'fuck that was bright' and was blinded for all eternity"

You're wrong. The giant farting bug said, "Aaaaaaaaah!!! I need Preparation H! I shouldn't have had that bean dip..."

kheegster · Post by **kheegster** » 2003-01-25 09:22pm

...and behold, the great Zod said:"I'm coming, I'm COMING........"...

UltraViolence83 · Post by **UltraViolence83** » 2003-01-28 04:56am

Hey, there's a contradiciton in astronomy that I keep seeing, I'd like some clearification... Ok, they say they've measured galaxies moving away form us, as well as each other, yet other sources say that Andromeda is coming towards us! Can someone please clear this up for me?

Arrow · Post by **Arrow** » 2003-01-28 08:11am

Andromeda is in the local group, so it and the Milky Way (and the other clouds of stars in the local group) have a gravitational pull on one another. The other galaxies are very distance, and the gravitation pull between us and them is almost nonexistant. Therefore they move away from us as the universe expands.

His Divine Shadow · Post by **His Divine Shadow** » 2003-01-28 08:27am

Durandal wrote:Space is expanding

Are we sure that space itself is expanding and not just the matter that inhabits space?

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