Does Antimatter exist in the universe anymore?

AI Thread Summary
Antimatter exists in the universe and can be created in laboratories, particularly in particle accelerators, where it is produced momentarily before annihilating with matter. While it is challenging to contain significant amounts of antimatter due to its tendency to annihilate upon contact with matter, ongoing research, such as the ALPHA collaboration, studies its properties. Antimatter is also naturally produced through processes like positron emission in proton-rich nuclei and is found in cosmic rays. The early universe likely contained nearly equal amounts of matter and antimatter, but an imbalance allowed some matter to survive annihilation, a phenomenon that remains a mystery. Overall, antimatter continues to be a subject of scientific inquiry, with implications for understanding the universe's composition and fundamental physics.
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If Antimatter was completely annihilated after the Big Bang, how is it that we have studied it. As well as artificially created it? If we can't create normal matter, why would we be able to create antimatter? And since we can, why doesn't it immediately get annihilated from the contact of the matter?
 
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Positrons are antimatter (widely used in medical devices). Antimatter has been created in laboratories.
 
Nova said:
If Antimatter was completely annihilated after the Big Bang, how is it that we have studied it. As well as artificially created it? If we can't create normal matter, why would we be able to create antimatter? And since we can, why doesn't it immediately get annihilated from the contact of the matter?

It depends on what you mean by 'create' matter. We can certainly transmute elements by using atom smashers, and there are nuclear reactions in which antimatter can be created momentarily before it annihilates with regular matter. What is difficult to do is to contain and accumulate significant quantities of antimatter with current technology.
 
Nova said:
If Antimatter was completely annihilated after the Big Bang, how is it that we have studied it. As well as artificially created it? If we can't create normal matter, why would we be able to create antimatter? And since we can, why doesn't it immediately get annihilated from the contact of the matter?
Hi Nova! There is an ongoing collaboration called ALPHA which studies antimatter;
Home page: http://alpha.web.cern.ch/
How Alpha works: http://alpha.web.cern.ch/howalphaworks
And a clip from that page, showing some of the equipment:


EDIT:
This clip was better (description of equipment and techniques):
 
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The simple fact is that we can create both matter and antimatter. We do this all the time in particle colliders.

Nova said:
And since we can, why doesn't it immediately get annihilated from the contact of the matter?

If we say "shortly" instead of "immediately", then it usually does. The exceptions are when we store antimatter in order to study it.
 
Not only do we routinely create matter and antimatter in particle accelerators, and store it in traps or rings, it's important to note that antimatter is created by nature all the time. Nuclei that are proton rich compared to stable nuclei decay via positron - anti-electron - emission!

Linked is a chart of all known nuclei, the number of protons are on the y axis, the number of neutrons on the x axis. The black squares are the stable isotopes, and everything that is coloured pink is a nucleus that decays via positron (β+) emission. http://upload.wikimedia.org/wikipedia/commons/7/79/NuclideMap_stitched_small_preview.png
 
In addition to what has already been said, we are also constantly bombarded with anti-matter in cosmic rays. For example, the AMS-02 experiment has measured the positron fraction in the electron and positron cosmic ray flux (see, e.g., http://www.ams02.org/wp-content/uploads/2013/03/Press_2.jpg). Between 5 and 15 percent of the total flux is positrons, depending on the energy you are looking at.
 
Also, there is the suggestion that to solve the baryon asymmetry problem, you can have large portions of the universe composed of antimatter, as opposed to matter. It's not a terribly popular view, and it's not supported by some observational evidence, but it's not completely laughable either.
 
The original photon-baryon ratio of the early universe is totally dependent on matter - antimatter annihilations.
 
  • #10
wouldn't helium be a better option than hydrogen? you get to study even anti neutrons..
 
  • #11
Tejaslion said:
wouldn't helium be a better option than hydrogen? you get to study even anti neutrons..

Who are you quoting? That is, who SAID it is hydrogen? I'm not finding that in the thread. Please use the quote button. Thanks.
 
  • #12
Anti matter is created continuously in the universe, just not in large quantities and it tends not to escape annihilation for very long. In the very early universe it is believed to have been almost as abundant as regular matter. There was, however, an imbalance that permitted a relatively miniscule amount of regular matter to survive annihilation. The reason for this is a mystery. All we know is it occurred before atoms had a chance to form.
 
  • #13
Drakkith said:
The simple fact is that we can create both matter and antimatter.
But antimatter and matter share the same properties right? So wouldn't it not make sense due to law of conservation?
 
  • #14
Generally, antiparticles have the same mass as their corresponding particles, but carry opposite quantum numbers (such as electric charge). Assuming that you have enough available energy and momentum to create the particle-antiparticle pair, no conservation laws are being violated.
 
  • #15
Nova said:
But antimatter and matter share the same properties right? So wouldn't it not make sense due to law of conservation?
What would make sense? Conservation of what?
 
  • #16
I keep seeing the word "create" over and over again. It is counter-intuitive. We should not be able to create matter, it exists and we are allowed to shape it, transform it, but not create it.
 
  • #17
nuuskur said:
I keep seeing the word "create" over and over again. It is counter-intuitive. We should not be able to create matter, it exists and we are allowed to shape it, transform it, but not create it.

That is simply not correct. Matter can be created and destroyed and it happens all the time. There's nothing counter-intuitive about it.
 
  • #18
Drakkith said:
That is simply not correct. Matter can be created and destroyed and it happens all the time. There's nothing counter-intuitive about it.

But matter is destroyed, its converted into energy via E=mc2 right?
Nova said:
But antimatter and matter share the same properties right? So wouldn't it not make sense due to law of conservation?

Just like what others said, it depends on the law of conservation of what. The law of conservation of charge holds because the particle-antiparticle pair have the same charge magnitudes but with opposite polarity (eg +e for a positron and -e for an electron). An annihilation of a particle-antiparticle pair does maintain conservation of energy and linear momentum, but the opposite phenomenon, called pair production (where a photon materializes into a particle-antiparticle pair), there must be a nearby massive object (eg. a nucleus) to maintain the law of momentum and energy conservation. The nucleus must be involved to carry away part of the initial photon momentum.
 
  • #19
nuuskur said:
I keep seeing the word "create" over and over again. It is counter-intuitive. We should not be able to create matter, it exists and we are allowed to shape it, transform it, but not create it.

Google for "pair production" - this is the process by which energy on the form of photons turns into an electron and an anti-electron.
 
  • #20
robotpie3000 said:
But matter is destroyed, its converted into energy via E=mc2 right?

Wrong. That is the theoretical maximum energy that can be extracted if you could create a 100% efficient process. Atom bombs, for example, as WAY far from 100% When matter is forced to change states, it is converted into many things, energy just being one of the possible ones, and it is usually as light and heat and other forms of matter. The heat is, I think, the main energy that one thinks of in atom bombs although there's a lot of light as well. I'm not sure what kind of particles are left over from the blast.
 
  • #21
phinds said:
Wrong. That is the theoretical maximum energy that can be extracted if you could create a 100% efficient process. Atom bombs, for example, as WAY far from 100% When matter is forced to change states, it is converted into many things, energy just being one of the possible ones, and it is usually as light and heat and other forms of matter. The heat is, I think, the main energy that one thinks of in atom bombs although there's a lot of light as well. I'm not sure what kind of particles are left over from the blast.

Ah thanks for that correction. So when a particle and its associated antiparticle collide and annihilate, only the "lost" mass is converted into energy, and the rest into the other forms you mentioned?
 
  • #22
An annihilation releases all the energy in the particles - the particles get annihilated and stop existing. 100% lost mass, sort of.

Nuclear weapons are not annihilation reactions, you transform atoms into different atoms. A tiny fraction (like 0.1% for fission) of their total energy gets released and the products have nearly the same mass of the original atoms (~0.1% less).
 
  • #23
robotpie3000 said:
Ah thanks for that correction. So when a particle and its associated antiparticle collide and annihilate, only the "lost" mass is converted into energy, and the rest into the other forms you mentioned?

Sorry, I was only talking about conversion. As mfb correctly pointed out, annihilation DOES release all of the energy
 
  • #24
How much anti-matter and matter would be required to create a Big Bang?
 
  • #25
Dryson said:
How much anti-matter and matter would be required to create a Big Bang?

The big bang was not an explosion. It was an expansion of space which resulted in a gradual reduction in the temperature and density of the universe over the past 13 billion years. In other words, the big bang was not a single explosive event, but a process of expansion.

You cannot create a big bang by annihilating matter and anti-matter.
 
  • #26
Drakkith said:
You cannot create a big bang by annihilating matter and anti-matter.
Well, you could in principle make a large bang, and even a big bang, but not a Big Bang. Luckily scientific language is so precise ;)
 
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  • #27
What is the difference in terms of spectrum ? Imagine you have isolated some element of antimatter and analysed it's spectrum (say anti-hydrogen) will it be same as normal matter hydrogen spectrum ?

If we find a distant galaxy made completely of antimatter , which is sufficiently away from other normal matter galaxies to avoid annihilation, will our telescopes be able to tell us that it's made of antimatter ?
 
  • #28
Monsterboy said:
What is the difference in terms of spectrum ? Imagine you have isolated some element of antimatter and analysed it's spectrum (say anti-hydrogen) will it be same as normal matter hydrogen spectrum ?
It should be the same, and several experiments are testing this with increasing precision (one example).

If we find a distant galaxy made completely of antimatter , which is sufficiently away from other normal matter galaxies to avoid annihilation, will our telescopes be able to tell us that it's made of antimatter ?
We should certainly see the boundary regions between antimatter and matter where annihilation would happen.
 
  • #29
mfb said:
We should certainly see the boundary regions between antimatter and matter where annihilation would happen.
Hannes Alfven in his, now very much dated, 1966 book Worlds-Antiworlds: Antimatter in Cosmology argued that initial annihilation at the boundary would create enough of radiation pressure to push the two kinds of matter apart and subsequently reduce the annihilation rate below detectable levels. I don't remember if he had any calculations there, it's been some years since I've read it. Still, the point can be made that this particular argument can be reasonably circumvented.

There are of course other serious issues with the picture, including the lack of a mechanism to separate matter and antimatter in bulk, but this one is not such a strong one.
 
  • #30
Bandersnatch said:
Hannes Alfven in his, now very much dated, 1966 book Worlds-Antiworlds: Antimatter in Cosmology argued that initial annihilation at the boundary would create enough of radiation pressure to push the two kinds of matter apart and subsequently reduce the annihilation rate below detectable levels. I don't remember if he had any calculations there, it's been some years since I've read it. Still, the point can be made that this particular argument can be reasonably circumvented.

There are of course other serious issues with the picture, including the lack of a mechanism to separate matter and antimatter in bulk, but this one is not such a strong one.
Well, that just opens up more questions. Where are those large surfaces without matter (of either kind)? Where are the antihelium nuclei AMS-02 is looking for?

We cannot fully rule out that model, but large amounts of antimatter look very problematic in many aspects.
 
  • #31
Drakkith said:
The big bang was not an explosion. It was an expansion of space which resulted in a gradual reduction in the temperature and density of the universe over the past 13 billion years. In other words, the big bang was not a single explosive event, but a process of expansion.

You cannot create a big bang by annihilating matter and anti-matter.

How can you expand space when only particles that are intractable with each other can expand?

Is space a particle?

all of space was contained in a single point - There had to have been some large explosion that created this single point in space otherwise we would be able to map the entirety of space based on the Big Bang Theory. But since our universe has a boundary to it I really don't think that we can say that all of space was contained in a single point.

http://en.wikipedia.org/wiki/Big_Bang
 
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  • #32
Dryson said:
How can you expand space when only particles that are intractable with each other can expand? Is space a particle?

Particles themselves don't expand, the distance between each particle increases. The same thing happens with the expansion of space. The distance between unbound objects increases over time. There are plenty of threads in the cosmology subforum about this.
 
  • #33
Dryson said:
How can you expand space when only particles that are intractable with each other can expand?
Intractable means "hard to control or deal with," like an intractable problem. I don't understand what you mean by "particles that are intractable with each other".
 
  • #34
vela said:
Intractable means "hard to control or deal with," like an intractable problem. I don't understand what you mean by "particles that are intractable with each other".

I meant to write particles that interact with each other in an energetic manner.
 
  • #35
Drakkith said:
Particles themselves don't expand, the distance between each particle increases. The same thing happens with the expansion of space. The distance between unbound objects increases over time. There are plenty of threads in the cosmology subforum about this.

If space was a particle then it would have an energetic interaction value present that can be tested. Space is also the distance between each particle that increases and decreases over time based upon particle interaction. If space was expanding then it would have an energetic value.

But since space cannot be tested as an energetic particle but can be proven to be a medium that particles move through perhaps space can be summed up as the residual value of anti-matter that was present in space before our Universe slowly cooled.

I still don't believe that space is expanding but rather the particles in space are moving through space.

I think Spock made the reference that "Space was the thing that was moving."
 
  • #36
@Dryson: That does not make sense at all.
Dryson said:
I still don't believe that space is expanding but rather the particles in space are moving through space.
This is not a question of belief. Particles moving through space are incompatible with our observations.
 
  • #37
Bandersnatch said:
Hannes Alfven in his, now very much dated, 1966 book Worlds-Antiworlds: Antimatter in Cosmology argued that initial annihilation at the boundary would create enough of radiation pressure to push the two kinds of matter apart and subsequently reduce the annihilation rate below detectable levels. I don't remember if he had any calculations there, it's been some years since I've read it. Still, the point can be made that this particular argument can be reasonably circumvented.

There are of course other serious issues with the picture, including the lack of a mechanism to separate matter and antimatter in bulk, but this one is not such a strong one.

mfb said:
Well, that just opens up more questions. Where are those large surfaces without matter (of either kind)? Where are the antihelium nuclei AMS-02 is looking for?

We cannot fully rule out that model, but large amounts of antimatter look very problematic in many aspects.

In early high school (not long after It was published), I was a big 'fan' of Alfven's book. I have a first printing. However, this book was a key part of what led me to pursue study of GR when I read claims it was inconsistent with GR. Indeed, it is fundamentally inconsistent with GR and the book seems blissfully unaware of key mathematical theorems of GR. In particular, this book proposes a cyclic cosmology, but the collapse phase as presented by Alfven would satisfy all conditions of the singularity theorems, so the benign re-expansion powered by boundary layer annihilation is a mathematical absurdity. This book is now only a nice historic curiosity by a very accomplished plasma physicist who seems never to have chosen to put in the effort to learn GR.
 
  • #38
Do we actually create matter in particle accelerators? I mean , sure we collide particles together but do we actually 'create' matter. If yes, then in what sense?
Also, I'd like to clarify: if all the antimatter was annihilated at the Big Bang, that must mean that there was more matter than antimatter to begin with. Was there? Why?
 
  • #39
UncertaintyAjay said:
Do we actually create matter in particle accelerators? I mean , sure we collide particles together but do we actually 'create' matter. If yes, then in what sense?
You could say "produce" or "make" if you like it better :). They don't get created from "nothing". See e.g. http://hyperphysics.phy-astr.gsu.edu/hbase/particles/accel.html and http://www.fnal.gov/pub/science/inquiring/questions/jackie.html.

UncertaintyAjay said:
Also, I'd like to clarify: if all the antimatter was annihilated at the Big Bang, that must mean that there was more matter than antimatter to begin with.
Have a look at http://en.wikipedia.org/wiki/Baryon_asymmetry.
 
  • #40
UncertaintyAjay said:
Do we actually create matter in particle accelerators? I mean , sure we collide particles together but do we actually 'create' matter. If yes, then in what sense?
The antimatter is not there before, and after the collision we have antimatter (and more matter). I would call that "create".
Also, I'd like to clarify: if all the antimatter was annihilated at the Big Bang, that must mean that there was more matter than antimatter to begin with. Was there? Why?
It does not mean that, see the wikipedia link for details.
 
  • #41
I was referring to Novas original statement, in which he said that all the antimatter was anhilliated, in which case there must have been more matter than antimatter. The explanations on the Wikipedia page refer to why we do not observe as much antimatter as we do matter . Or how more matter than anti matter could be produced
 
  • #42
It goes down to basic relativity... matter and energy cannot either be created or destroyed, only changed from one form to another just like a match going from solid matter to plasma by the addition of heat.

Antimatter, despite the connotation follow the same rules as matter... the big misunderstanding is that antimatter is destructive to matter, and it's not. A molecule of water will interact with its antimatter counterpart it will interact with it as if it were any other molecule. The antimatter particle is a MIRROR image of OUR particles. The charges positions of electrons would be reversed.

The Law of Conservation Mass/Energy states that mass/energy ARE the same thing and cannot be created or destroyed, only transformed from one to the other i.e. My monitor is shooting photons that have mass, it is actually shooting matter at me ONLY because it is plugged into the socket. The electricity TRANSFORMS in mass that I can see.

Antimatter is interesting, takes too much energy to feasibly "convert" mass into anitmatter tho. I'm sure it wil change drastically soon and who knows how they may benefit/hurt us...
 
  • #43
My over all point being, yes antimatter CAN be created and converted due to Laws of Relativity and the fact that anitmatter IS mass and reacts like all other mass relatively.
 
  • #44
chkneater said:
It goes down to basic relativity... matter and energy cannot either be created or destroyed, only changed from one form to another just like a match going from solid matter to plasma by the addition of heat.

Matter can be created and destroyed, it happens every day at the LHC and other particle colliders.

Antimatter, despite the connotation follow the same rules as matter... the big misunderstanding is that antimatter is destructive to matter, and it's not. A molecule of water will interact with its antimatter counterpart it will interact with it as if it were any other molecule. The antimatter particle is a MIRROR image of OUR particles. The charges positions of electrons would be reversed.

This is incorrect. A molecule of water interacting with its equivalent antimatter molecule WILL result in an annihilation of both molecules. Note that a normal interaction between two water molecules involves a close range repulsion from their respective electrons. Replace one molecule of water with its antimatter equivalent and you no longer have a repulsion between electrons, but a strong attraction between the electrons and the positrons. The end result is annihilation.

The Law of Conservation Mass/Energy states that mass/energy ARE the same thing and cannot be created or destroyed, only transformed from one to the other i.e. My monitor is shooting photons that have mass, it is actually shooting matter at me ONLY because it is plugged into the socket. The electricity TRANSFORMS in mass that I can see.

This is also incorrect. Conservation laws do not state that mass and energy are the same thing and indeed they are not. Einsteins equation e=mc2 is commonly claimed to tell us that mass and energy are the same thing, but this is also incorrect. The equation tells us that an amount of energy added or removed from a system results in an amount of mass added or removed to the system, with the amount of mass determined by the equation. Mass and energy are NOT the same thing in physics, though they are related. Also, photons do not have mass even though they have energy.

Antimatter is interesting, takes too much energy to feasibly "convert" mass into anitmatter tho. I'm sure it wil change drastically soon and who knows how they may benefit/hurt us...

Unlikely. Matter/antimatter creation using particle colliders is a very complicated process and it is very unlikely we are going to drastically increase the efficiency in the process anytime soon.
 
  • #45
Unfortunately this thread has generated a lot of pseudoscience and personal theories for responses lately that have had to be deleted. Since the original question has been answered adequately I am going to lock this thread to prevent more troublesome replies.
 
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