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Antihydrogen Trapped For 1000 Seconds

technologyreview.com

11–20 of 109 posts

Re: Antihydrogen Trapped For 1000 Seconds

#11

"The ALPHA team now plans to cool a small lump of antihydrogen ..." How do you cool something at this scale? And how about when it can't collide with any normal matter?

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).

Re: Antihydrogen Trapped For 1000 Seconds

#12
post #10

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?

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!

Re: Antihydrogen Trapped For 1000 Seconds

#14
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.

Re: Antihydrogen Trapped For 1000 Seconds

#15

"The ALPHA team now plans to cool a small lump of antihydrogen ..." How do you cool something at this scale? And how about when it can't collide with any normal matter?

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).

Of course they interact with photons. Photons are how electric and magnetic fields are propagated. So if they can be contained by an electromagnetic trap, they interact with photons.

Re: Antihydrogen Trapped For 1000 Seconds

#16
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.

Re: Antihydrogen Trapped For 1000 Seconds

#17

"The ALPHA team now plans to cool a small lump of antihydrogen ..." How do you cool something at this scale? And how about when it can't collide with any normal matter?

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.

Re: Antihydrogen Trapped For 1000 Seconds

#18
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?

No. I am not a physicist, but my understanding is that certain devices that have been proposed for use in space manipulation devices (e.g. wormholes, alcubierre drive), require either a form of matter that has reverse gravity or thousands of times the available energy of the known universe.

http://en.wikipedia.org/wiki/Worm_hole#Traversable_wormholes http://en.wikipedia.org/wiki/Alcubierre_drive

Re: Antihydrogen Trapped For 1000 Seconds

#19
post #16
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.

I think the "falling up" argument comes from the conception that antimatter is the time-reverse of matter.

Re: Antihydrogen Trapped For 1000 Seconds

#20
post #14
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.

Not to mention that it would take a LOT of mass to balance out the weight of the board and the person riding it.
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