Originally posted by Metal Brain How can matter be dispersed without an explosion?
Your question seems to assume it wasn't fairly homogeneously distributed in the first place. Particle production happened during reheating at the end of the inflationary era so it it happened everywhere in causally connected patches at the same time.
Originally posted by Metal Brain "Further there was nothing in Hawkings lecture notes that contradicts anything I've said here."
What Humy said contradicts Hawking, you are making the claim that because we can see back in time by observing stars and galaxies we have proof the big bang was not an explosion. Explosion or not, we can't see back that far. Do you agree or disagree?
What Humy said contradicts Hawking,
Which part of what he said?
And, since his opinions of the big bang doesn't necessarily represent the generally preferred theory on the big bang in particular, why would it matter if I did say something that contradicted him? Many good cosmologists rightly or wrongly disagree with his opinions on this.
He wasn't the one that made the big bang theory and he isn't considered to hold some kind of special privileged authority on it over and above that of the many other cosmologists that rightly or wrongly disagree with him.
Explosion or not, we can't see back that far.
actually, we can via indirect observation. Just one example: the microwave background radiation that matches the predicted echo of the big bang. What is stopping us seeing that in the present day?
Originally posted by DeepThought Your question seems to assume it wasn't fairly homogeneously distributed in the first place. Particle production happened during reheating at the end of the inflationary era so it it happened everywhere in causally connected patches at the same time.
I figured since Hawking said it was a singularity where the laws of physics break down until the expansion it was not already distributed.
I did read a little about it on a physics forum though. I think I see where you are coming from now. I did a search using the words "expanding time" because I found it hard to believe space could expand without time expanding. Someone on that forum explained it with a 2D surface with objects attached. The 2D surface is a balloon and blowing up the balloon was like space expanding. The small objects would move away from each other even though they are in a fixed position.
Is this the general idea you are trying to get across? If so, does it explain why the expansion is accelerating?
Originally posted by Metal Brain "Further there was nothing in Hawkings lecture notes that contradicts anything I've said here."
What Humy said contradicts Hawking, you are making the claim that because we can see back in time by observing stars and galaxies we have proof the big bang was not an explosion. Explosion or not, we can't see back that far. Do you agree or disagree?
I am not making such a claim. I am not responsible for humy's posts. The claim I was making was that by observing ancient stars and very distant galaxies we can conclude that the laws of physics haven't changed in 13 billion years.
Whether you regard the big bang as an explosion or not depends on what you think an explosion is. I don't think it is ridiculous to refer to it as one.
We can see the cosmic microwave background which happened 300,000 years after the big bang, and in the future we may be able to detect the cosmic neutrino background at 1 second after the big bang. Looking at anisotropies in the CMB gives us information about earlier epochs, naturally we can't "see" from before then as the universe was opaque in that era.
Further the evidence for the Big Bang is that distant galaxies are receding from us with a velocity proportional to their distance. So the entire theory hangs on observation of luminous objects that must have been formed no earlier than of the order of 100 million years after the big bang.
Originally posted by DeepThought I am not making such a claim. I am not responsible for humy's posts. The claim I was making was that by observing ancient stars and very distant galaxies we can conclude that the laws of physics haven't changed in 13 billion years.
Whether you regard the big bang as an explosion or not depends on what you think an explosion is. I don't think it is ...[text shortened]... that must have been formed no earlier than of the order of 100 million years after the big bang.
I did some slight edits to my last post because I realized I didn't explain it as well as I could have.
Can you explain why the expansion is accelerating?
Space and time are unequivocally linked. Space cannot expand unless time expands with it. Space expanding explains why the universe is expanding. Time expanding explains why the universe is accelerating.
Originally posted by Metal Brain I did some slight edits to my last post because I realized I didn't explain it as well as I could have.
Can you explain why the expansion is accelerating?
At the present time, the accelerating expansion is thought to be coming from a force we have not figured out as of yet. All we have right now is the observation that is best explained by postulating the universal expansion is accelerating. They didn't postulate a fundamental law about that as of yet. There are theories but nothing is written in concrete yet.
Originally posted by sonhouse At the present time, the accelerating expansion is thought to be coming from a force we have not figured out as of yet. All we have right now is the observation that is best explained by postulating the universal expansion is accelerating. They didn't postulate a fundamental law about that as of yet. There are theories but nothing is written in concrete yet.
Originally posted by Metal Brain I did some slight edits to my last post because I realized I didn't explain it as well as I could have.
Can you explain why the expansion is accelerating?
Your edit made me lose track a little. The accelerating expansion isn't something that is well understood. In Einstein's theory one can add a term to the Einstein Field equations called the cosmological constant. Einstein did that as an ad hoc way of keeping the universe static, then they discovered it was expanding so the term was dropped for years. An accelerating expansion implies a cosmological term, but no one has any very good ideas about why there should be such a term. The catch-all phrase to describe this is Dark Energy, but there isn't a particularly good hypothesis as to what dark energy is.
Originally posted by Metal Brain The assertion that the big bang was not an explosion. I am asking for proof because I don't believe anybody has it. That is all I dispute. Many posters on here seem to think I am disputing the big bang theory which is not the case at all. Can't you people read?
The Big Bang Theory is based on the observation that space is expanding. The obvious conclusion is that at one time it started from a very small point and expanded outwards to what it is today. This is expansion of space, not expansion in space, the later being called an explosion. You are, in fact disputing the Big Bang Theory, as the expansion of space is what it is all about.
Originally posted by Metal Brain Here is my theory:
Space and time are unequivocally linked. Space cannot expand unless time expands with it. Space expanding explains why the universe is expanding. Time expanding explains why the universe is accelerating.
Now, tell me. What is wrong with my theory?
answer:
1, "time expands" makes no sense. What does "time expands" mean? "expands" in what sense? why don't you elaborate on that and just tell us?
2, you clearly are not a physicist. To have any credible chance of having a valid new cosmological theory that rivals the current models, you must at the very least have studied and understood basic physics and that includes all the mathematics of that physics.
Actually, even that is probably not enough for it is probably also essential you also have studied and understand all the current models including all the mathematical side of them. If you haven't, it is extremely unlikely indeed that you can make a good valid new cosmological theory which is why not even I would try and make one despite my physics background!
You haven't even understood the concept of expanding space so you fail to understanding what the Big Bang theory is thus you are in no position to begin speculating on alternative theories.
Originally posted by twhitehead The Big Bang Theory is based on the observation that space is expanding. The obvious conclusion is that at one time it started from a very small point and expanded outwards to what it is today. This is expansion of space, not expansion in space, the later being called an explosion. You are, in fact disputing the Big Bang Theory, as the expansion of space is what it is all about.
'The obvious conclusion is that at one time it started from a very small point and expanded outwards to what it is today"
That is what I thought based on Hawking's link, but deepthought seems to disagree. He claims it was not at a small point or singularity.
"This is expansion of space, not expansion in space"
That is what I am talking about, expansion of space. How can space expand without time expanding? The two go together. If they didn't, objects (matter) could be at the same place at once. This is not orderly enough for us to exist.
I am not disputing the big bang at all. Reread what I wrote.
Originally posted by KazetNagorra An explosion is the expansion of some substance, usually a (flammable) gas, within space.
The Big Bang describes the (rapid) expansion of space.
True, but any rapid expansion can be described as an explosion, even space. My point is that something is not just dragging the matter along, but accelerating it. I am saying the acceleration is time expanding with the space.
Just as time is passing at a slight difference here on earth than in space above it so is the outer part of space because time is relative. Do you see where I am coming from?
1, "time expands" makes no sense. What does "time expands" mean? "expands" in what sense? why don't you elaborate on that and just tell us?
2, you clearly are not a physicist. To have any credible chance of having a valid new cosmological theory that rivals the current models, you must at the very least have studied and understood basic physics an ...[text shortened]... the Big Bang theory is thus you are in no position to begin speculating on alternative theories.
"1, "time expands" makes no sense. What does "time expands" mean? "expands" in what sense? why don't you elaborate on that and just tell us?"
Space without time? How can that be possible? If that were true 2 objects could be at the same place in space. Time prevents that from happening.
It is as if you are not thinking of time as being relative as you should.
25 Aug '14 20:29
NASA has said the big bang is a misnomer
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