Are scientists overthinking a question on anti-matter?

[Themohawkninja]

I just watched a video explaining what anti-matter is, and the studies being done to determine if the anti-particles are exactly equal to their counter-parts. One question that the narrator stated science wants to answer is "why is the universe mainly matter, and not anti-matter?". Isn't that a silly question to ask, because if the universe was primarily anti-matter, wouldn't we (in the alternate reality) consider it to be normal matter, and thereby consider what we (in this reality) consider normal matter to be anti-matter?

[Xeutack]

Probably, but that is a deterministic approach and doesn't really explain why in particular the matter containing negative electrons and positive protons emerged more abundant... or why one of the types of matter even ended up more abundant than the other at all.

[K^2]

The question isn't why it's just matter and not anti-matter. The question is why there isn't the same amount of both.

In every experiment we have ever been able to conduct, we produce equal amounts of matter and anti-matter. Not a single known reaction produces more of one or the other. Not a one. Yet, here we are, in the universe filled with one and not the other. Of course, we chose to call the one that's in abundance matter and the other anti-matter. Which is which isn't really a big problem. But where did all this matter come from? Seems to be from big-bang. But then where is all the anti-matter that should have been created along the way?

There are several different hypotheses on the matter, and I won't get into details. Either way, however, it points to limitations of our knowledge, and figuring out the answer will be a major breakthrough in fundamental physics.

[Themohawkninja]

The question isn't why it's just matter and not anti-matter. The question is why there isn't the same amount of both.

In every experiment we have ever been able to conduct, we produce equal amounts of matter and anti-matter. Not a single known reaction produces more of one or the other. Not a one. Yet, here we are, in the universe filled with one and not the other. Of course, we chose to call the one that's in abundance matter and the other anti-matter. Which is which isn't really a big problem. But where did all this matter come from? Seems to be from big-bang. But then where is all the anti-matter that should have been created along the way?

There are several different hypotheses on the matter, and I won't get into details. Either way, however, it points to limitations of our knowledge, and figuring out the answer will be a major breakthrough in fundamental physics.

If it isn't too much trouble, could you link, or at least name those theories for me to research?

[K^2]

This is a good place to start: Baryogenesis.

Edit: They only discuss the spontaneous symmetry breaking as an option. (Universe starting with zero baryon number.) But there are some hypotheses that are based on baryon number starting out non-zero. Simplest having to do with geometry of the space-time and suggesting that anti-matter is "before" the big-bang. All of this goes way beyond Standard Model, however.

Edited June 24, 2013 by K^2

[Brabbit1987]

The question isn't why it's just matter and not anti-matter. The question is why there isn't the same amount of both.

In every experiment we have ever been able to conduct, we produce equal amounts of matter and anti-matter. Not a single known reaction produces more of one or the other. Not a one. Yet, here we are, in the universe filled with one and not the other. Of course, we chose to call the one that's in abundance matter and the other anti-matter. Which is which isn't really a big problem. But where did all this matter come from? Seems to be from big-bang. But then where is all the anti-matter that should have been created along the way?

There are several different hypotheses on the matter, and I won't get into details. Either way, however, it points to limitations of our knowledge, and figuring out the answer will be a major breakthrough in fundamental physics.

Could not have said it better myself. Anti-matter is a real mystery. However, it's to be expected, since we don't actually know that much about all the laws of physics. I think the last video I watched with an CERN Scientist said we only know a small percentage of physics, like 5% or 6% or something.

[Brotoro]

The antimatter that was created in about equal quantities with matter during the early phases of our universe's evolution was all annihilated, and that energy is now in the cosmic background radiation. The Big Question is why there was a little more matter than antimatter to begin with...since that small leftover bit is what we are made of.

[K^2]

I think the last video I watched with an CERN Scientist said we only know a small percentage of physics, like 5% or 6% or something.

97% of statistics are made up on the spot. The percentage you quote has no chance of being accurate other than by mere chance, and even then, highly dependent on how you choose to gauge the fraction.

The most important thing you should understand about science is that while it answers many practical questions, like how we would go about building a bridge, it doesn't actually answer any fundamental questions, like why any of that is true. Or even whether it's actually true, for that matter. Pretty much all of the physics we've known turned out to be wrong, and what little that hasn't looks very suspicious. But science isn't about finding truth. It's about finding practical models. By that measure, there is no guarantee that it's even possible to know how things actually work. So what fraction of the unknowable do we actually know? Is there even a way to answer such a question?

[Person012345]

I just watched a video explaining what anti-matter is, and the studies being done to determine if the anti-particles are exactly equal to their counter-parts. One question that the narrator stated science wants to answer is "why is the universe mainly matter, and not anti-matter?". Isn't that a silly question to ask, because if the universe was primarily anti-matter, wouldn't we (in the alternate reality) consider it to be normal matter, and thereby consider what we (in this reality) consider normal matter to be anti-matter?

Yes, and in such a case it would be "why is it most this stuff"

The problem is that anti-matter and matter should be created in equal parts. Yet we see a predominance of one over the other. Why?

[Giggleplex777]

What about the neutral long kaon? They produce on average slightly more positrons than electrons.

[Brabbit1987]

97% of statistics are made up on the spot. The percentage you quote has no chance of being accurate other than by mere chance, and even then, highly dependent on how you choose to gauge the fraction.

The most important thing you should understand about science is that while it answers many practical questions, like how we would go about building a bridge, it doesn't actually answer any fundamental questions, like why any of that is true. Or even whether it's actually true, for that matter. Pretty much all of the physics we've known turned out to be wrong, and what little that hasn't looks very suspicious. But science isn't about finding truth. It's about finding practical models. By that measure, there is no guarantee that it's even possible to know how things actually work. So what fraction of the unknowable do we actually know? Is there even a way to answer such a question?

I don't think I was viewing that as some type of super accurate percentage but thanks for explaining things I already knew lol. I merely pointed that out as an example of how little we actually know, which leads to why we know so little about anti-matter.

Also, you know, I am more likely to believe someone from CERN then you, so no offense. Though I most certainly do agree with you lol because you stated the obvious to me.

[WestAir]

I don't think I was viewing that as some type of super accurate percentage but thanks for explaining things I already knew lol. I merely pointed that out as an example of how little we actually know, which leads to why we know so little about anti-matter.

Also, you know, I am more likely to believe someone from CERN then you, so no offense. Though I most certainly do agree with you lol because you stated the obvious to me.

K^2 actually works in the field of physics. For all intents and purposes, his words should hold just as much weight as any other professional scientist.

[metaphor]

It could be possible that matter and antimatter do exist in equal parts in the universe. We just happen to live in a part where due to random chance, matter is more plentiful by about 1 part in 100,000. We can only see the 92 billion light-year wide observable universe, but this might be only a tiny part of the entire universe.

[K^2]

What about the neutral long kaon? They produce on average slightly more positrons than electrons.

This is slightly misleading. They produce equal number of both, since charge is a conserved quantity, and K_L is a neutral particle. However, it is slightly more likely to first decay into a À^- + e⁺ than À⁺ + e^-. This is a major puzzle, and it might hint at the preference for one kind of matter over the other, but not the reason for why it's not the same of both. The pion (À^±) is still going to eventually decay into e^± and you end up with equal number of particles and anti-particles produced.

[Brabbit1987]

K^2 actually works in the field of physics. For all intents and purposes, his words should hold just as much weight as any other professional scientist.

Right, but this is on a forum. One, I didn't know that, and two, proof? While it's not that I don't believe it, it's just I am still more likely to believe someone who I can clearly see. Then you also have to ask, does he work in particle physics? Theoretical physics? What field of physics does he work in?

It's the same reason why my words as a game developer means nothing here on these forums. It's also the same reason why when someone talks about a particular game, I may not know what it is.

Last, you also have to consider, which person knows more? Which person has more experience? So no, his words can't be held to the same degree as someone I absolutely know, has the experience and knowledge and clearly works for CERN.

Course as I said before, it's not like I disagree anyway with what he said earlier. I simply just wanted to mention that.

[Brotoro]

I've read a good sampling of K^2's posts over time, and I can tell that he appears to know of what he speaks.

[K^2]

For the record, I am a Ph.D. Candidate, doing research in particle theory with focus on non-perturbative quantum field theory and meson structure. If you need links to any of my conference talks, I can provide them. As for whether I'm as qualified as a CERN scientist would depend on the scientist and the topic. Statistically, a random CERN scientist is likely to have more experience. And if we start talking about specifics of the experiments, I'm going to be way out-classed by almost any experimentalist. But in terms of theory, I am going to at very least know where bounds of my understanding are.

[Brabbit1987]

I've read a good sampling of K^2's posts over time, and I can tell that he appears to know of what he speaks.

Yep I agree, never said he didn't. :3

For the record, I am a Ph.D. Candidate, doing research in particle theory with focus on non-perturbative quantum field theory and meson structure. If you need links to any of my conference talks, I can provide them. As for whether I'm as qualified as a CERN scientist would depend on the scientist and the topic. Statistically, a random CERN scientist is likely to have more experience. And if we start talking about specifics of the experiments, I'm going to be way out-classed by almost any experimentalist. But in terms of theory, I am going to at very least know where bounds of my understanding are.

Pretty neat. Wish I was that smart lol. Well, then again, I think I should say instead, wish I wasn't so lazy since I am not exactly stupid either XD.

Edited June 24, 2013 by Brabbit1987

[bsalis]

If there was perfect symmetry we would not be here to talk about it. That's a sort of obvious answer.

Only a very small asymmetry is required. Just because it has not been seen/proven yet does not mean it does not exist.

[K^2]

Only a very small asymmetry is required. Just because it has not been seen/proven yet does not mean it does not exist.

It's not just asymmetry. Every known process conserves lepton and baryon numbers. Yet for there to be an imbalance due to an asymmetry, these numbers must not be conserved. Instead, the difference of the two should be a conserved quantity. Some models predict such a thing, but there is no experimental confirmation. Direct or indirect.

[Thaniel]

In a more macro perspective, a possible sollution, or explanation, could be that at the time of creation of our "current" universe, instead of the Big-bang bubble expanding more or less like a bubble from a center point, it could have exanded into two (I´ll be scientificly acurate here now, so be warned) "blobs", much like the hourglass nebula (MyCn 18). That way, one of the "blobs" could start out life with a more "positive charge" if you like and the other with a more negative charge. The total balance of particles would still hold true, but each half of the universe could be made up of predominantly matter or antimatter.

Just a thought thogh.

[LewisTherin]

In a more macro perspective, a possible sollution, or explanation, could be that at the time of creation of our "current" universe, instead of the Big-bang bubble expanding more or less like a bubble from a center point, it could have exanded into two (I´ll be scientificly acurate here now, so be warned) "blobs", much like the hourglass nebula (MyCn 18). That way, one of the "blobs" could start out life with a more "positive charge" if you like and the other with a more negative charge. The total balance of particles would still hold true, but each half of the universe could be made up of predominantly matter or antimatter.

Just a thought thogh.

The standard cosmological model and observational evidence suggest that the universe doesn't have a center, rather everything is expanding away from everything else as a result of the stretching of space. It's not an explosion with objects moving through space from the middle, rather clumpy bits of matter are basically stationary and the co-ordinate system is getting larger, the wiki article on the topic can probably explain it better:

https://en.wikipedia.org/wiki/Metric_expansion_of_space

The idea that one particular direction or area of the universe would be made up of antimatter is (depending on what scale you're looking at) contrary to the cosmological principle that the universe is basically the same no matter which direction you look in or from where you look. On a relatively small scale you could have galaxies that have formed from antimatter scattered around the place, but if there was a particular bias in their location we'd have a lot of explaining to do.

[DerekL1963]

It could be possible that matter and antimatter do exist in equal parts in the universe. We just happen to live in a part where due to random chance, matter is more plentiful by about 1 part in 100,000. We can only see the 92 billion light-year wide observable universe, but this might be only a tiny part of the entire universe.

The problem with this theory is that it breaks a fundamental tenet of cosmology, one that underlies pretty much all physics as we understand it - the universe is more or less the same everywhere. Now this principle may in fact turn out to be false, but you have to demonstrate that falsehood before proposing a theory that requires it to be false.

[Mr Shifty]

Pretty much all of the physics we've known turned out to be wrong. . .But science isn't about finding truth. It's about finding practical models.

I'm an engineer, not a scientist, so maybe that's why this statement strikes me as a bit odd. For all intents and purposes, practical models are the truth. We trust our instruments and models to the degree to which they allow us to make practically accurate predictions. This is really the only objective measure of truth. And physics hasn't turned out to be wrong; it is possible to predict -- with high accuracy -- a wide range of phenomena using only Newtonian mechanics. Physics has turned out to be approximate, but is still almost always Good Enough®.

[metaphor]

The problem with this theory is that it breaks a fundamental tenet of cosmology, one that underlies pretty much all physics as we understand it - the universe is more or less the same everywhere. Now this principle may in fact turn out to be false, but you have to demonstrate that falsehood before proposing a theory that requires it to be false.

The cosmological principle asserts that the laws of physics are the same everywhere in the universe. This can be true even if there are bubbles of matter and antimatter. Both matter and antimatter would follow the same laws of physics.

The large-scale structure part of the cosmological principle is based on our observation of the observable universe and is not a physical law by itself. It is something that is approximately true in our (92 billion light year) corner of the universe but it is not known outside of that.

The matter and antimatter bubble theory is something that could be tested, for example if we found a small gradient in the matter distribution between opposite ends of the observable universe. It is something like Newton's law of gravity getting replaced by general relativity. Newton's gravity is still observably true, just not in large enough gravitational fields. The cosmological principle could still be observably true, just not at large enough scales.