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Antihydrogen Trapped For 1000 Seconds

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Re: Antihydrogen Trapped For 1000 Seconds

#61

Post by Killah911 »

swombat wrote: post #33
jwuphysics wrote: post #31

Earlier quoted context omitted.

If you were holding onto a chunk of antimatter you would probably be missing a hand.

1 megaton nuke is about 4000 TeraJoules of energy. 10g of antimatter yields about 10^15 Joules - i.e. 1 PetaJoule, or the equivalent of a 2+ Megaton nuke. If you were holding onto a chunk of antimatter large enough to hold onto you'd be missing half of London.

Not sure if that conclusion is right. It probably wouldn't result in an explosion and the energy output would probably be in the form of light. Regardless, I'm going with Stephen Hawking on this one: "If you ever meet your anti-self, don't shake hands!"

Re: Antihydrogen Trapped For 1000 Seconds

#62

Post by lloeki »

sp332 wrote: post #16
ordinary wrote: post #7

I am nothing short of _astounded_ that we don't know if anti-matter "falls up".

I've never heard anyone argue that it would react any differently to gravity than normal matter. After all, the only difference is the electrical charge of the particles. They have the same mass.

So if it "reacts the opposite" to gravity, what does that mean?

I would see no reason for Newton's law to not hold true around our scale, so repelling means F=Gm1m2/r^2 which only makes sense if one of the masses is actually negative. Just the thought of it looks like fun.

Re: Antihydrogen Trapped For 1000 Seconds

#64

Post by burgerbrain »

hippich wrote: post #32
pavel_lishin wrote: post #12

Earlier quoted context omitted.

Well, technically, it wouldn't be possible for a chunk of antimatter to be heavier than you. But yeah, one theory is that if you hold one that's more massive than you are, its repulsion would overpower your attraction, and bang, zoom, straight to the moon!

it should be repelled by moon's gravity back to earth - recursion... =))

https://secure.wikimedia.org/wikipedia/en/wiki/Lagrangian_po...

Re: Antihydrogen Trapped For 1000 Seconds

#65

Post by burgerbrain »

Killah911 wrote: post #61
swombat wrote: post #33

Earlier quoted context omitted.

1 megaton nuke is about 4000 TeraJoules of energy. 10g of antimatter yields about 10^15 Joules - i.e. 1 PetaJoule, or the equivalent of a 2+ Megaton nuke. If you were holding onto a chunk of antimatter large enough to hold onto you'd be missing half of London.

Not sure if that conclusion is right. It probably wouldn't result in an explosion and the energy output would probably be in the form of light. Regardless, I'm going with Stephen Hawking on this one: "If you ever meet your anti-self, don't shake hands!"

"It probably wouldn't result in an explosion and the energy output would probably be in the form of light."

That's what nukes do too. Turns out that dumping absurd amounts of light (various parts of the spectrum, but certainly including visible) into the surrounding area absurdly fast tends to fuck stuff up pretty good.

Re: Antihydrogen Trapped For 1000 Seconds

#67

Post by Someone »

Dn_Ab wrote: post #50
Someone wrote: post #40

Earlier quoted context omitted.

I do not understand: - I think all photons fall down in a gravitational field. - you claim photons are their own antiparticle. Hence, antiphotons fall down in a gravitational field. How then would antimatter fall upwards ~because~ it is the antiparticle of matter? Am I wrong in 'knowing' that all light bends the same under gravity?

Best as I can tell I don't think we disagree. You are saying that antimatter should react the same way with respect to gravity as matter does right? Then I agree. I do not think antimatter will be found to fall up or be repelled.

You are right. I must have mixed up two replies.

Re: Antihydrogen Trapped For 1000 Seconds

#69

Post by Typhon »

By the way, there's something I've been wondering about for a long time. I read somewhere that there are no antiphotons and antimatter emits light just the same as normal matter. So, I assume that there's no way to tell whether a photon was emitted by antimatter or by matter.

Therefore, how do we know distant galaxies aren't made of antimatter ?

Maybe there's an obvious answer, but as far as I know, the only thing we can know about these galaxies, we know because of the radiation they emit.

Re: Antihydrogen Trapped For 1000 Seconds

#70

Post by othermaciej »

Typhon wrote: post #69

By the way, there's something I've been wondering about for a long time. I read somewhere that there are no antiphotons and antimatter emits light just the same as normal matter. So, I assume that there's no way to tell whether a photon was emitted by antimatter or by matter. Therefore, how do we know distant galaxies aren't made of antimatter ? Maybe there's an obvious answer, but as far as I know, the only thing we…

I've wondered this myself. An explanation I have heard from a physisicist is: if there were regions of the universe where antimatter is dominant, the boundaries where they border normal matter space would be extremely bright from the annihilation reactions. Apparently even very thin interstellar gas would generate a lot of energy in matter/antimatter annihilations.
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