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Antihydrogen Trapped For 1000 Seconds

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Re: Antihydrogen Trapped For 1000 Seconds

#31

Post by jwuphysics »

Femur wrote: post #10
coderdude wrote: post #4

Earlier quoted context omitted.

From the article: "The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down." One reason they would like to know if antimatter is repelled by gravity is that it could explain why the Universe is expanding at an accelerating rate.[1] [1]: http://www.physorg.com/news/2011-04-antimatter-gravity-unive...

>>"The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down." Would this mean that if I am "holding onto" a chunk of antimatter heaver than myself I will fall up into space?

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

Re: Antihydrogen Trapped For 1000 Seconds

#32

Post by hippich »

pavel_lishin wrote: post #12
Femur wrote: post #10

Earlier quoted context omitted.

>>"The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down." Would this mean that if I am "holding onto" a chunk of antimatter heaver than myself I will fall up into space?

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... =))

Re: Antihydrogen Trapped For 1000 Seconds

#33

Post by swombat »

jwuphysics wrote: post #31
Femur wrote: post #10

Earlier quoted context omitted.

>>"The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down." Would this mean that if I am "holding onto" a chunk of antimatter heaver than myself I will fall up into space?

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.

Re: Antihydrogen Trapped For 1000 Seconds

#34

Post by enko »

gecko wrote: post #14
dadro wrote: post #13

If it is proven that that anti-matter is repelled by gravity does that mean hover-boards will become a reality in our lifetimes? What are some of the potential practical applications?

Given that antimatter explodes violently when put into contact with regular matter, I kind of hope that's not how they go about achieving this. A kid who forgets to recharge his board, allowing the magnetic fields to collapse, could do a considerable amount of damage.

> I kind of hope that's not how they go about achieving this

Don't worry. The design is impractical anyway - regulating the "anti-mass" would be extremely difficult. Just when you got it balanced, the kid would drink a glass of water and the board would sink into the ground.

Due caution would indeed be advisable when selling these gadgets, though. A matter-antimatter collision of 50kg would be equivalent to about 2.1 gigatons of TNT, or about 400 times more powerful than the most powerful hydogen bomb ever developed, so it would indeed caused a "considerable amount of damage".

Re: Antihydrogen Trapped For 1000 Seconds

#35

Post by pavel_lishin »

enko wrote: post #34
gecko wrote: post #14

Earlier quoted context omitted.

Given that antimatter explodes violently when put into contact with regular matter, I kind of hope that's not how they go about achieving this. A kid who forgets to recharge his board, allowing the magnetic fields to collapse, could do a considerable amount of damage.

> I kind of hope that's not how they go about achieving this Don't worry. The design is impractical anyway - regulating the "anti-mass" would be extremely difficult. Just when you got it balanced, the kid would drink a glass of water and the board would sink into the ground. Due caution would indeed be advisable when selling these gadgets, though. A matter-antimatter collision of 50kg would be equivalent to about 2.1…

> The design is impractical anyway

Nah, you just need a miniature collider inside the board, manufacturing more anti-matter as necessary.

And obviously, it would be powered by annihilating matter/antimatter together, via a small Mr. Fusion at the back.

Re: Antihydrogen Trapped For 1000 Seconds

#36

Post by simpleTruth »

viraptor wrote: post #23
gecko wrote: post #14

Earlier quoted context omitted.

Given that antimatter explodes violently when put into contact with regular matter, I kind of hope that's not how they go about achieving this. A kid who forgets to recharge his board, allowing the magnetic fields to collapse, could do a considerable amount of damage.

Not saying that it's as feasible as normal engine, but when you ride a bike you pretty much fill it with matter that explodes violently when ignited. Then you ignite small parts of it to make the bike move... We may still see some normal devices which use antimatter in one way or another.

Meaningful amounts of Mater + antimatter produces extreme amounts of radiation, and takes ridiculous amounts of energy to produce.

To put things into perspective, 1kg (~2.2lb) of antimater + 1kg of matter = 2* (9×10^16 J/kg) of energy, TNT = 4.2×10^6 J/kg so that works out to 42,000,000,000 kg of TNT or a 100 mega ton bomb which is larger than the largest H bomb ever tested.

PS: The other issue is unlike gas which is fairly stable, any sort of containment failure = detonation.

Re: Antihydrogen Trapped For 1000 Seconds

#37

Post by icegreentea »

ordinary wrote: post #7

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

Well, the point of science is that we don't know until we observe it. So it shouldn't be that astounding since we've had a ridiculously hard time getting large amounts of neutral antimatter (everything before was charged, so EM affects overwhelmed gravitational). The consensus seems to be that antimatter will behave 'normally'. but we haven't seen it yet. Also, it turns out that certain frameworks where anti-matter is repelled by matter gravity doesn't violate anything else that hasn't already been violated (for example, CP and CPT symmetry have already be observed to be broken). And thus the uncertainty.

Re: Antihydrogen Trapped For 1000 Seconds

#38

Post by StavrosK »

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... =))

Not unless it's in a tube, and it would quickly reach an equilibrium anyway.

Re: Antihydrogen Trapped For 1000 Seconds

#39

Post by StavrosK »

enko wrote: post #34
gecko wrote: post #14

Earlier quoted context omitted.

Given that antimatter explodes violently when put into contact with regular matter, I kind of hope that's not how they go about achieving this. A kid who forgets to recharge his board, allowing the magnetic fields to collapse, could do a considerable amount of damage.

> I kind of hope that's not how they go about achieving this Don't worry. The design is impractical anyway - regulating the "anti-mass" would be extremely difficult. Just when you got it balanced, the kid would drink a glass of water and the board would sink into the ground. Due caution would indeed be advisable when selling these gadgets, though. A matter-antimatter collision of 50kg would be equivalent to about 2.1…

So you're saying that this has fantastic military applications? Interesting...

Re: Antihydrogen Trapped For 1000 Seconds

#40

Post by Someone »

Dn_Ab wrote: post #17
SeveredCross wrote: post #11

Earlier quoted context omitted.

Possibly with something like http://en.wikipedia.org/wiki/Laser_cooling , where you're not actually striking it with matter, but only with photons, though I don't know if photons react with antimatter (I presume not, but I am not a particle physicist).

Antimatter is just matter moving backwards in time, so it interacts with photons (which by the way, is its own antiparticle). This is one line of reasoning which strongly suggests antimatter should fall down not up in a gravitionational field. although iirc Dark matter is something does not interact with light.

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?

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