Antimatter

[jizum3434]

hey does anybody know any thing about antimatter, or a good site where i can learn more about it, or just some quick comments about it would be cool thanks guys!

[Tormod]

Try CERN:

 

http://livefromcern.web.cern.ch/livefromcern/antimatter/

[jizum3434]

thanks alot

[Dark Mind]

I have a "quick question" (<-- ask Tormod about those B)), can you see anti-matter?

[UncleAl]

hey does anybody know any thing about antimatter, or a good site where i can learn more about it, or just some quick comments about it would be cool thanks guys!

 

http://livefromcern.web.cern.ch/livefromcern/antimatter/history/AM-history01.html

 

Start with vacuum. Pump in energy big time. Conservation laws must be met! The vacuum will spark into matter and antimatter to balance the books. Matter and antimatter are utterly indistinguishable, with two exceptions:

 

1) The Weak Interaction is strictly left-handed. Beta-decay is not symmetric, antimatter vs. matter. You can do an experiment in a hermetically sealed containment and still tell one from the other.

 

http://physics.nist.gov/GenInt/Parity/parity.html

http://physicsweb.org/articles/world/16/7/8

 

2) If matter and antimatter touch you get 100% conversion to energy, E=mc^2. 0.0465 gram overall is a kilotonne nuclear equivalent.

 

Would you like to own some antimatter? Potassium-40 in potassium chloride salt substitute has a positron decay channel. It emits an anti-electron that annihalates with an electron to give two 511 KeV photons. A bottle of that salt substitute will make a Geiger counter click.

[Qfwfq]

can you see anti-matter?

If you found an entire solid object made of it, it would interact with light in much the same way as the comparable object made of ordinary matter. Each electric charge is opposite but this wouldn't make a difference to incident photons.

[bumab]

It was my impression that "matter" and "anti-matter" are really arbitrary designations, like positive and negitive charge. Is that true? I've seen contrary reports on the subject.

[Qfwfq]

Quite true! See PCT theorem and so on. Our world is made of one, it could just as well be made of the other. One of the Cosmological Riddles is about how the choice came about, though I personally wouldn't rule out different galaxies being one or the other, even at a roughly 50-50 distribution.

 

One slight remark on what I said yesterday: offhand, I would expect light polarization to be inverted. If you could handle a crystal of some asymmetric molecules, dissolving it in anti-water after having noted whether it is L or R, and then shining linear polarized light through the solution, you should see the opposite rotation compared to the normal molecule of the same geometry.

[TeleMad]

I have a "quick question" (<-- ask Tormod about those ;)), can you see anti-matter?

 

If you mean with the naked eye, under non-controlled conditions, I doubt it. You can't see something unless it is non-microscopic. And to get something even as small as the smallest visible molecule would require having trillions (or whatever) anti-matter atoms bonded together. Before that much anti-matter could aggregate it would encounter normal matter and undergo mutual annihilation.

 

Scientists have made an anti-atom, using an anti-proton as the nucleus and a positron as the "orbiting" particle. It didn't last long because they couldn't prevent it from encountering normal matter. I'm not sure, but I think that scientists may have since then created something larger than anti-hydrogen.

[Biochemist]

Would you like to own some antimatter? Potassium-40 in potassium chloride salt substitute has a positron decay channel. It emits an anti-electron that annihalates with an electron to give two 511 KeV photons. A bottle of that salt substitute will make a Geiger counter click.

UA- I was so impressed by this slice of eclectic trivia that I perused your site (posted in your profile). It is fair to say that it exceeded my wildest expectations for insight, humor and, perhaps most importantly, multi-axis irreverence.

 

My conclusion is that you really ought to consider running for senator. It is concievable that you could convert congressional hearings into events as informative and newsworthy as the Daily Show.

 

Where do I sign up to join your fan club?

[Qfwfq]

If you mean with the naked eye, under non-controlled conditions, I doubt it. You can't see something unless it is non-microscopic. And to get something even as small as the smallest visible molecule would require having trillions (or whatever) anti-matter atoms bonded together. Before that much anti-matter could aggregate it would encounter normal matter and undergo mutual annihilation.

Although I agree that it would be difficult to produce a sizeable hunk of antimatter and to manipulate it, espescially here on Earth, this doesn't mean that you wouldn't see a large hunk of it if you passed by one out in space.

 

Anyway, a small but visible speck could be manipulated in a vacuum if, for instance, it is electrically charged. Handle with care... :friday:

 

P. S. I'm not so sure about what I said Friday concerning polarization effects being inverted, I haven't really worked it out but EM conserves parity seperately and the electric dipole moments ought to count regarless of the single charges...