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Author Topic: What would a ball of anti-matter look like? Anti-matter periodic table?  (Read 1947 times)

Offline Europan Ocean

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If a ball of anti-matter, perhaps the lightest solid kind were made, and it was suspended with no contact with matter, in a vacuum chamber, with a clear viewing glass, when looked upon under light, what would it look like? Would light destroy it?

Is there a possible anti-matter periodic table?

Does anti-matter have weight?


 

Offline Ethos_

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If a ball of anti-matter, perhaps the lightest solid kind were made, and it was suspended with no contact with matter, in a vacuum chamber, with a clear viewing glass, when looked upon under light, what would it look like? Would light destroy it?
It's appearance, IMHO, wouldn't be any different than ordinary matter. And no, light is neutrally charged. The photon is it's our anti particle.
Quote from: Europan Ocean
Is there a possible anti-matter periodic table?
Yes
Quote from: Europan Ocean
Does anti-matter have weight?
Yes, if you mean "mass" when referring to "weight" we can presume it to be identical to an equivalent mass of normal matter.
« Last Edit: 13/07/2016 17:38:34 by Ethos_ »
 

Offline syhprum

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I wrote and almost identical reply but an errant computer wiped it out before I could post it !!!
 

Offline PmbPhy

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If a ball of anti-matter, perhaps the lightest solid kind were made, and it was suspended with no contact with matter, in a vacuum chamber, with a clear viewing glass, when looked upon under light, what would it look like? Would light destroy it?

Is there a possible anti-matter periodic table?

Does anti-matter have weight?
Ethos is correct. Antimatter looks exactly like normal matter. That's due to the fact that the energy levels of the positrons in antimatter atoms have the same values as their corresponding values in atoms made from normal matter. In fact which particles are called "matter" is arbitrary. Once a decision is made as to which ones to call matter and which is antimatter the convention is maintained. The corresponding antiparticles are determined by that standard and have opposite values for the various parameters which define the particle such as charge and spin. However the mass of a particle is the same as the mass of its corresponding antiparticle.

And yes, antimatter has weight. Keep in mind that when I say that it has weight it means that it has a gravitational force on it when placed in a gravitational field, i.e. if you were to place it on a weight scale then the reading would read non-zero.
 

Offline evan_au

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Is there a possible anti-matter periodic table?
Yes there is, but with current techniques it takes an enormous amount of energy to produce anti-protons, then slow them down enough to combine with anti-electrons to form anti-hydrogen.

The LHC has produced a limited amount of neutral anti-hydrogen gas, and has perfected ways of storing it for at least 15 minutes without it annihilating with nearby "normal matter" atoms.

They are using this anti-hydrogen to confirm their assumption that anti-matter experiences the same gravitational attraction as normal matter.

However, creating elements higher on the anti-periodic table is a real challenge, because while protons and electrons are stable, neutrons are not. So to produce anti-helium, they would need to create anti-neutrons and combine them with the anti-protons before the anti-neutrons decayed (which is expected to take around 15 minutes, on average).

Neutrons are hard to contain and direct (and anti-neutrons are even harder, since they would tend to annihilate with anything that was trying to direct them).

Producing anti-helium with an anti-hydrogen bomb would be even more problematic (as would collecting the anti-helium atoms afterwards).
 
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Offline jerrygg38

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If a ball of anti-matter, perhaps the lightest solid kind were made, and it was suspended with no contact with matter, in a vacuum chamber, with a clear viewing glass, when looked upon under light, what would it look like? Would light destroy it?
It's appearance, IMHO, wouldn't be any different than ordinary matter. And no, light is neutrally charged. The photon is it's our anti particle.
Quote from: Europan Ocean
Is there a possible anti-matter periodic table?
Yes
Quote from: Europan Ocean
Does anti-matter have weight?
Yes, if you mean "mass" when referring to "weight" we can presume it to be identical to an equivalent mass of normal matter.
   There is the possibility of antimatter galaxies which would repel matter galaxies. The difference between a photon and an anti-photon is a difference such that the positive electrical energy and the negative electrical energy take opposite positions. One wave may lead and the other lag. Light from an anti-matter galaxy will switch position when entering a matter galaxy.
  The anti-matter galaxy will look like our galaxy with the same physical properties.
 

Offline PmbPhy

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Quote from: jerrygg38
   There is the possibility of antimatter galaxies which would repel matter galaxies.
Antimatter behaves identically to matter in a gravitational field. That means that antimatter galaxies won't repel matter galaxies.

Quote from: jerrygg38
The difference between a photon and an anti-photon is a difference such that the positive electrical energy and the negative electrical energy take opposite positions.
The photon is its own antiparticle, i.e. the photon doesn't have an antiparticle meaning that there's no such thing as an antiphoton. See http://www.newenglandphysics.org/other/WE_Lamb_antiphoton.pdf
 

Offline PmbPhy

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Quote from: evan_au
Yes there is, but with current techniques it takes an enormous amount of energy to produce anti-protons, ...
Why is that? It takes no more energy to create an anti-proton than it does to create a proton. The problem is that it would take an enormous amount of energy to create a handful of antimatter.
 

Offline jerrygg38

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Quote from: jerrygg38
   There is the possibility of antimatter galaxies which would repel matter galaxies.
Antimatter behaves identically to matter in a gravitational field. That means that antimatter galaxies won't repel matter galaxies.


The photon is its own antiparticle, i.e. the photon doesn't have an antiparticle meaning that there's no such thing as an antiphoton. See http://www.newenglandphysics.org/other/WE_Lamb_antiphoton.pdf
Since the gravitational field is so weak and antimatter is hard to get, how are they able to measure that what you specify is true?

  As far as the photon is concerned you only see ordinary photons in our gravitational field. How do you know that antiphotons do not switch physically when they are made initially or when they enter a matter oriented gravitational field? I have no definite opinion on this possibility.
 

Offline PmbPhy

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Quote from: jerrygg38
Since the gravitational field is so weak and antimatter is hard to get, how are they able to measure that what you specify is true?
It hasn't been done yet. Just as you were writing what you thought was the case theoretically, so was I. But what I wrote really is what is theoretically predicted. An antiparticle is merely a article having the exact same proper mass but opposite charge, spin, etc of the particle in question. But there is no way to determine what is matter and what is antimatter. Those distinctions are arbitrary. All that matters is that that for every particle there is another particle with the same proper mass but its other properties are opposite.

Quote from: jerrygg38
  As far as the photon is concerned you only see ordinary photons in our gravitational field. How do you know that antiphotons do not switch physically when they are made initially or when they enter a matter oriented gravitational field? I have no definite opinion on this possibility.
Theory, that's how. How do you know otherwise? By that I mean to ask what you based your answer on. I'm assuming that you based it on what you believe the current theory (in this case relativistic cosmology/particle physics) says will happen, correct? I'm actually curious as to where you got the idea that antimatter has antigravity properties. Please tell us where you got that idea from.

You appear to be thinking in terms of what's true and what's not true or what's been "proved" etc.. Those concepts don't belong in science. Every scientist knows that.

I'd like to make one point very clear right now. Almost all questions that are asked in this forum are theoretical questions. That means that if someone asks a question its assumed that they want to know what current theory says will happen. And that's the case in this thread.
« Last Edit: 14/07/2016 17:31:16 by PmbPhy »
 

Offline chiralSPO

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Quote from: evan_au
Yes there is, but with current techniques it takes an enormous amount of energy to produce anti-protons, ...
Why is that? It takes no more energy to create an anti-proton than it does to create a proton. The problem is that it would take an enormous amount of energy to create a handful of antimatter.

I think issue here is that we don't have to make protons to study them--we just need to isolate them from the environment. We do have to make the antiprotons, which, as you point out is quite energy-intensive.
 

Offline syhprum

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The only way we going to get a look at balls of anti matter higher up in the periodic table is to visit a planet in an anti matter galaxy (if such things exist) when we would have considerable problems landing and getting around
 

Offline jerrygg38

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Quote from: jerrygg38
Since the gravitational field is so weak and antimatter is hard to get, how are they able to measure that what you specify is true?
It hasn't been done yet. Just as you were writing what you thought was the case theoretically, so was I. But what I wrote really is what is theoretically predicted. An antiparticle is merely a article having the exact same proper mass but opposite charge, spin, etc of the particle in question. But there is no way to determine what is matter and what is antimatter. Those distinctions are arbitrary. All that matters is that that for every particle there is another particle with the same proper mass but its other properties are opposite.

Quote from: jerrygg38
  As far as the photon is concerned you only see ordinary photons in our gravitational field. How do you know that antiphotons do not switch physically when they are made initially or when they enter a matter oriented gravitational field? I have no definite opinion on this possibility.
Theory, that's how. How do you know otherwise? By that I mean to ask what you based your answer on. I'm assuming that you based it on what you believe the current theory (in this case relativistic cosmology/particle physics) says will happen, correct? I'm actually curious as to where you got the idea that antimatter has antigravity properties. Please tell us where you got that idea from.

You appear to be thinking in terms of what's true and what's not true or what's been "proved" etc.. Those concepts don't belong in science. Every scientist knows that.

I'd like to make one point very clear right now. Almost all questions that are asked in this forum are theoretical questions. That means that if someone asks a question its assumed that they want to know what current theory says will happen. And that's the case in this thread.
  I wanted to know what the present theory is. So I ask about  possible alternatives. Now I can go back to new theories and propose how my Dot-wave theory explains the photon and anti-photon since my concepts of the photon is adaptability.
 

Offline evan_au

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Quote from: PmbPhy
Why is that? It takes no more energy to create an anti-proton than it does to create a proton.
CERN "creates" protons by taking hydrogen gas, and passing it through an arc to ionize it. Energy: a bit over 13 eV per proton.

CERN "creates" antiprotons by accelerating the above protons to around 26,000,000,000 eV, and smashing them into an iridium target. This produces an antiproton/proton pair with rest mass of 938,000,000 eV/c2 each at a very high kinetic energy, plus a mess of other debris totaling around  24,000,000,000 eV.

You then have to "catch" the antiprotons with a magnetic field (hard with high energy particles traveling in random directions) before they annihilate with the next atom they meet (like a nearby atom in the iridium target). I suspect that capturing the antiprotons has a very low efficiency.

Overall, "creating" antiprotons requires billions of times more energy than "creating" protons.
See: https://en.wikipedia.org/wiki/Antiproton#Modern_experiments_and_applications
 

Offline PmbPhy

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Quote from: PmbPhy
Why is that? It takes no more energy to create an anti-proton than it does to create a proton.
CERN "creates" protons by taking hydrogen gas, and passing it through an arc to ionize it. Energy: a bit over 13 eV per proton.

CERN "creates" antiprotons by accelerating the above protons to around 26,000,000,000 eV, and smashing them into an iridium target. This produces an antiproton/proton pair with rest mass of 938,000,000 eV/c2 each at a very high kinetic energy, plus a mess of other debris totaling around  24,000,000,000 eV.

You then have to "catch" the antiprotons with a magnetic field (hard with high energy particles traveling in random directions) before they annihilate with the next atom they meet (like a nearby atom in the iridium target). I suspect that capturing the antiprotons has a very low efficiency.

Overall, "creating" antiprotons requires billions of times more energy than "creating" protons.
See: https://en.wikipedia.org/wiki/Antiproton#Modern_experiments_and_applications
Okay. I see what you meant now. While you think of 938 MeV as an enormous amount of energy, I don't. Think about it like I do in order to see my point: 938 MeV is about the rest energy of a neutron and therefore the rest energy of nuclei are tens to hundreds times that, depending on the nucleus in question. So 938 MeV is small when you're dabbling in nuclear physics. Think about how much energy 938 MeV is in terms of joules [J]: 938 MeV = 1.50 x 10-10 J. Keep in mind that 1.00 J = amount of work done by a force or 1 N acting over a distance of 1 m.

That means that in these terms 938 MeV is a very little amount of energy. On what basis do you think of it as being an enormous amount of energy? Even 24,000,000,000 eV = 24 TeV is extremely small on the joule scale.
 

Offline agyejy

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Okay. I see what you meant now. While you think of 938 MeV as an enormous amount of energy, I don't. Think about it like I do in order to see my point: 938 MeV is about the rest energy of a neutron and therefore the rest energy of nuclei are tens to hundreds times that, depending on the nucleus in question. So 938 MeV is small when you're dabbling in nuclear physics. Think about how much energy 938 MeV is in terms of joules [J]: 938 MeV = 1.50 x 10-10 J. Keep in mind that 1.00 J = amount of work done by a force or 1 N acting over a distance of 1 m.

That means that in these terms 938 MeV is a very little amount of energy. On what basis do you think of it as being an enormous amount of energy? Even 24,000,000,000 eV = 24 TeV is extremely small on the joule scale.

I would speculate that evan is thinking on a per particle basis. In that sense 26 GeV is about 4.1657e-9 J per each particle. A chemically useful amount to mess around with would probably be on the order of a tenth of a mole or 6.022140857e22 particles. So creating an amount of material this why that humans would even begin to approach the human scale would take 2.50864322e14 J or about .06 megatons (.05995801195 megatons to be overly precise). Even if we cut the amount by a factor of 100 so only a thousandth of a mole of particles is made (a truly tiny amount by microscopic standards) it would still require .0006 megatons or 700 Megawatt hours. That much energy might keep the lights on in a town for awhile and yet in only makes about .001 grams of anti-hydrogen.

edit: whoops picked up a factor of 1000. Should have been Gev not TeV.

« Last Edit: 15/07/2016 19:09:19 by agyejy »
 

Offline agyejy

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For contrast ionizing 0.001 mole of hydrogen into free protons takes about 0.0003484 Kilowatt hours. Your average home uses somewhere in the 10s of Kilowatt hours per day on average (depending on what is happening). So you could make an entire mole of protons in your house via ionization and it would barely register on your bill.
 

Offline evan_au

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Quote from: evan_au
with current techniques it takes an enormous amount of energy to produce anti-protons...
As Star Trek observed, antimatter is the ideal fuel for a spaceship. It has a fantastic specific impulse, a thousand times better than the long-sought controlled hydrogen fusion reaction.

But the energy cost of generating antimatter is so high (>>26 GeV per anti-proton) and the production rate is so low that rocket scientists have stayed with the miserable specific impulse of chemical rockets for getting payloads off the ground.

Perhaps CERN should replace their iridium target with dilithium?

Of course, if someone did produce a significant amount of antimatter, there is the risk of containment failure (a plot twist that was utilized in a number of Star Trek episodes), as well as the certainty of weaponization.
 

Offline Alan McDougall

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If you could do the impossible and get close enough and look at it, it would look exactly the same as a ball of matter, mirrored!

Alan
 

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