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Antihydrogen Trapped For 1000 Seconds

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Re: Antihydrogen Trapped For 1000 Seconds

#101

Post by lutorm »

burgerbrain wrote: post #65
Killah911 wrote: post #61

Earlier quoted context omitted.

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.

Yeah, a lot of the power output from a nuclear explosion is in gamma rays, and even air is opaque enough to gamma rays that the energy deposition heats it up to way incandescent temperatures. That's what the fireball of a nuclear explosion is: incandescent air.

Re: Antihydrogen Trapped For 1000 Seconds

#102

Post by InclinedPlane »

VladRussian wrote: post #96
InclinedPlane wrote: post #91

Earlier quoted context omitted.

We know that dark matter cannot be baryonic matter (atoms) for two reasons. First, models of the big bang that have been confirmed by experiment closely bound the total amount of baryonic matter in the Universe. Second, dark matter doesn't seem to behave the same way that baryonic matter behaves (normal matter clumps, dark matter doesn't appear to do so).

>...models of the big bang that have been confirmed by experiment ... to put it mildly, it is a very overreaching statement. >Second, dark matter doesn't seem to behave the same way that baryonic matter behaves (normal matter clumps, dark matter doesn't appear to do so). double whammy - we couldn't observe dark matter and we couldn't observe its clumps. Or consider it another way - while it supposedly have gravitatio…

http://en.wikipedia.org/wiki/Baryon_acoustic_oscillations

http://en.wikipedia.org/wiki/Cosmic_microwave_background_rad...

http://en.wikipedia.org/wiki/Dark_matter#Galaxy_clusters_and...

Re: Antihydrogen Trapped For 1000 Seconds

#104

Post by VladRussian »

jxcole wrote: post #18
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?

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

>thousands of times the available energy of the known universe.

the pieces of Universe that is more than 13B light years from us are moving with speed faster than light relative to us. The machinery behind it is space expansion. And by definition that is using energy less or equal to the universe's energy. So that is the start. The Alcubierre drive is the idea of how to use the same principle on much smaller scale. It is very doubtful that it would require more energy than moving the whole galaxies [which, let me repeat, are moving faster than light relative to us and to each other]

Re: Antihydrogen Trapped For 1000 Seconds

#105

Post by vl »

jacques_chester wrote: post #87
Tuna-Fish wrote: post #76

Earlier quoted context omitted.

Assuming 1kg of antimatter can be used to hover 1kg of matter and that your hoverboard could carry 80kg, should it's containment fail, it would detonate with the force of 3.4 gigatons of tnt. That's roughly equivalent with the entire present nuclear arsenal of the united states, and would cause 3rd degree burns out of direct thermal radiation over 300 kilometers away. So, umm, no .

Antimatter is definitely ridiculously dangerous stuff in macro quantities. Though strictly speaking, from a bomb-building point of view, it would be very difficult to design a weapon where matter-antimatter mixing happened more or less completely and simultaneously. Otherwise you "merely" have a series of uncontrolled multi-megatonne explosions in an increasingly large area, instead of a single multi-gigatonne explos…

Hmm, how about using two nukes to create light pressure from the two ends of initially split charge of hydrogen and anti-matter hydrogen? Or, however challenging by itself - creating spherical cavity in the hydrogen bomb to push normal matter to antimatter in the cavity for awhile.

Re: Antihydrogen Trapped For 1000 Seconds

#107

Post by natep »

qntm wrote: post #78
natep wrote: post #52

Earlier quoted context omitted.

Doesn't look like your odds are good (consensus atm is there's no theoretical basis): http://www.reddit.com/r/askscience/comments/h28sd/is_there_a...

That reddit post (and admittedly it is just a reddit post) actually says the opposite: there is no theoretical basis for antimatter not to behave exactly like regular matter in the presence of a gravitational field. The null hypothesis (and, in the absence of any strong evidence to the contrary, the stronger hypothesis) is that antimatter and matter respond to gravity in exactly the same way.

That's what I said. The person making the bet is betting on attraction, so the response was betting on repulsion, and I responded to the latter.

Re: Antihydrogen Trapped For 1000 Seconds

#108

Post by Tuna-Fish »

jacques_chester wrote: post #87
Tuna-Fish wrote: post #76

Earlier quoted context omitted.

Assuming 1kg of antimatter can be used to hover 1kg of matter and that your hoverboard could carry 80kg, should it's containment fail, it would detonate with the force of 3.4 gigatons of tnt. That's roughly equivalent with the entire present nuclear arsenal of the united states, and would cause 3rd degree burns out of direct thermal radiation over 300 kilometers away. So, umm, no .

Antimatter is definitely ridiculously dangerous stuff in macro quantities. Though strictly speaking, from a bomb-building point of view, it would be very difficult to design a weapon where matter-antimatter mixing happened more or less completely and simultaneously. Otherwise you "merely" have a series of uncontrolled multi-megatonne explosions in an increasingly large area, instead of a single multi-gigatonne explos…

That "increasingly large area" would fall entirely inside the fireball (and likely within a few-meter radius), and the detonation would basically indistinguishable from it all going off in one go.

Disintegrating the device is a serious problem for nuclear bombs, because when they break themselves up, they leave otherwise good material unused. For an antimatter bomb, splashing the AM uncontrollably would, if anything, speed up the initiation. (After the AM and the normal matter around it is ionized, the particles home for the closest thing to annihilate with. AM basically does all the work of the weapons designer for him.)

Re: Antihydrogen Trapped For 1000 Seconds

#109

Post by swombat »

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.

Funny that I actually managed to get the maths wrong. 4000 TeraJoules is 4 PetaJoules, i.e. 10g of antimatter is actually a 0.25 Megaton nuke. Still packs some serious punch, but I totally fail at arithmetic, it seems.
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