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Old 11th November 2017, 12:07 PM   #41
Ron_Tomkins
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So what exactly does the theory posit in the first place? That for every piece of matter, there should be an antimatter equal? There should be an antimatter Ron Tomkins, and an antimatter Empire State, and an antimatter Mona Lisa?

If this is so, and the Universe is supposed to be comprised of bits of matter-antimatter pairings, aren't these destined to clash and annihilate each other, thus producing.... nothing in the end? And if so, is this what Michio Kaku means by "the universe shouldn't exist"?
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Old 12th November 2017, 03:41 AM   #42
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Originally Posted by alexi_drago View Post
Not that I know much about it but have a question, is it known what stage or epoch particle-anti particle annihilation could occur? As in would it (or not) occur in the quark epoch, would it occur at the very moment of the big bang, is there any time it wouldn't have occurred but then a condition reached in the universe that did allow it?
I'll have to go back and look it up, but very early. Annihilation of course can happen at any time, but there was a period wherein the average photon collisions were high enough energy to produce proton/anti-proton pairs, and that's when the matter and anti-matter would both have been produced. During that period there was a balance between the annihilation events and production events and you would have had similar numbers of photons to matter particles.

When things cooled off enough the photons didn't have as much energy and weren't producing proton/anti-proton pairs anymore, but those that were around were still able to annihilate. At that point they quickly did so. Whatever asymmetry there was would have arisen before this transition period and we were left with matter and no anti-matter.

I'm not sure about the exact time frame off the top of my head, but we're talking extremely short times. Its certainly earlier than 1 second after the Big Bang, but I'm not sure how much earlier.
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Old 12th November 2017, 07:51 AM   #43
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Originally Posted by Ron_Tomkins View Post
So what exactly does the theory posit in the first place? That for every piece of matter, there should be an antimatter equal? There should be an antimatter Ron Tomkins, and an antimatter Empire State, and an antimatter Mona Lisa?

If this is so, and the Universe is supposed to be comprised of bits of matter-antimatter pairings, aren't these destined to clash and annihilate each other, thus producing.... nothing in the end? And if so, is this what Michio Kaku means by "the universe shouldn't exist"?
Photon collisions in an extremely high energy environment can result in proton/anti-proton pair production. This always produces both matter and anti-matter particles, partly due to conservation principles.

If you start out with the same amount of matter as anti-matter and things cool off so no more are being produced, then the naive assumption is that you should be left with the same amount.

We're not.

That's weird.

The suggestion is that more of the anti-matter than matter decayed before annihilating, and so there as less of it left over. So when it was all annihilated there was still some excess matter.

But that only works if there's a difference between matter and anti-matter, and a recent experiment looking for the specific differences that could allow that turned out not to show any differences.

So that's still weird.

But no, no one has suggested an anti-Ron Tomkins. But if you do run into someone who looks like you and he holds out his left hand...
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Old 12th November 2017, 08:12 AM   #44
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Originally Posted by Roboramma View Post
Photon collisions in an extremely high energy environment can result in proton/anti-proton pair production. This always produces both matter and anti-matter particles, partly due to conservation principles.

If you start out with the same amount of matter as anti-matter and things cool off so no more are being produced, then the naive assumption is that you should be left with the same amount.

We're not.

That's weird.

The suggestion is that more of the anti-matter than matter decayed before annihilating, and so there as less of it left over. So when it was all annihilated there was still some excess matter.

But that only works if there's a difference between matter and anti-matter, and a recent experiment looking for the specific differences that could allow that turned out not to show any differences.

So that's still weird.

But no, no one has suggested an anti-Ron Tomkins. But if you do run into someone who looks like you and he holds out his left hand...
Got it. So as long as we shake with the right hand, it should be ok then
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