9 ms·
Antihydrogen Trapped For 1000 Seconds
- martinkallstrom 15y ago$100 says antimatter is also attracted by gravity. Anything else would be too cool for school.
- enko 15y agoFuck it, you're on. $100. I want to believe ...
- natep 15y agoDoesn'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_any_theoretical_basis_for_antimatter/ http://www.reddit.com/r/askscience/comments/h28sd/is_there_a...
- enko 15y agoWell, let's see what the data says. I confess I want the universe to surprise and confound. I want the theories to be wrong, I want reality to be stranger than fiction. That would be awesome! Or I am wrong, in which case I'll happily pay out[1]. I'm a layman, as if that wasn't obvious, and it will be a much-needed physics lesson. Win-win. [1] If in Australia, payout will take the form of alcohol credits at an establishment of winner's choosing. Hey, I want to learn from my superiors :) If not, a crisp USD$100 note will be posted to any mailing address in the world, to be supplied.
- martinkallstrom 15y agoI want the theories to be wrong too, it's just that I'm a sceptic in this case simply because of the utter awesomness that would be the result. I will happily spend more than $100 just on delivery if that is required to make a payout in liquor (local Swedish flavors) across the world. Crisp paper is fully acceptable as well :) Doubt we will ever settle this though... I have painfully little faith in scientific breakthroughs.
- Fargren 15y agoWell, it would be really cool and confounding if gravity made antimatter move sideways. But I don't think that's likely.
- andrewflnr 15y agoIndeed, considering that there are 360 degrees of sideways. Which one? :)
- deleted 15y ago[deleted]
- qntm 15y agoThat 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.
- natep 15y agoThat'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.
- InclinedPlane 15y agohttp://en.wikipedia.org/wiki/Gravitational_interaction_of_antimatter#Supernova_1987A http://en.wikipedia.org/wiki/Gravitational_interaction_of_an...
- anigbrowl 15y agoI'm with you on this one. If antimatter was just backwards everything then there'd be large conspicuous clusters of the stuff all over the cosmos because ordinary matter would be repelling it instead of annihilating it. While there does seem to be a lot of dark matter out there, if it were actually antimatter and had opposite gravity to normal matter one would imagine there would be a huge discrepancy between cosmologists' models and observation. The high-end supercomputer simulations and regressions cosmologists employ have good predictive power, even though we lack a full explanation for the phenomena we can observe. Cosmologists deal with such far-out concepts to begin with (by definition) that it's not as if they'd be averse to a concept like antigravity if it had predictive utility. toys idly with desk magnets while thinking about it Then again, given that photons are massless maybe there could be such a thing as a gravitational dipole... /timecube
- othermaciej 15y agoWe know two things about dark matter: - It doesn't interact electromagnetically. - It does interact gravitationally and produces extra gravitational attraction beyond the electromagnetically interacting matter we know about. - It is dispersed throughout galaxies. The first property rules out baryonic antimatter as dark matter, since that would interact electromagnetically. The last two properties rule out anything that has a repulsive gravitational interaction as dark matter.
- VladRussian 15y ago>We know two things about dark matter: while we don't know whether it exists at all. Whatever phenomena are explained by DM are also easy explained by molecular hydrogen (i.e H2) which is almost not detectable. [The hydrogen we know about in the space is atomic - H, and there should be orders of magnitude more of molecular one than atomic when you have atomic at such interstellar space conditions]
- InclinedPlane 15y agoWe 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).
- kingsidharth 15y agoWon't it have it's own flavor of gravity? As in a force that attracts matter together and a force that attracts anti matter together?
- aufreak3 15y agoIt is actually great that they're doing this experiment 'cos if it turned out in a way that contradicted theory (which I think says "antimatter falls") then we might have to re-examine a whole lot of things! For example, if antimatter rises, there ought to be a statistical preference for black holes to emit antimatter. One of the posters on that site said CPT violation would be another great thing to check. Hell yeah!
- unwantedLetters 15y agoFor those of us that don't know anything about it, can someone explain the significance of this achievement?
- deleted 15y ago[deleted]
- coderdude 15y agoFrom 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-universe-expansion.html http://www.physorg.com/news/2011-04-antimatter-gravity-unive...
- Femur 15y ago>>"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?
- pavel_lishin 15y agoWell, 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!
- danparsonson 15y ago"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?
- SeveredCross 15y agoPossibly with something like http://en.wikipedia.org/wiki/Laser_cooling 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).
- sp332 15y agoOf 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.
- SeveredCross 15y agoI think I should've been more specific—I know that the two interact, but I wasn't sure if they /react/. That is, would collision between photons and antimatter produce the same sort of decay as matter-antimatter collision. Some research suggests that it indeed would.
- BoppreH 15y agoIf they can be trapped using photons for this long, I guess they don't react?
- Dn_Ab 15y agoAntimatter 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.
- ordinary 15y agoI am nothing short of _astounded_ that we don't know if anti-matter "falls up".
- sp332 15y agoI'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.
- smosher 15y agoI think the "falling up" argument comes from the conception that antimatter is the time-reverse of matter.
- delinka 15y agoOr perhaps must be affected by antigravity the way matter is by gravity. Assuming antigravity exists. Whether that's correct at all I don't know, but that's the logic being used.
- machrider 15y agoOf course, regular old hydrogen "falls up", being lighter than air. :) I guess if gravity is truly reversed for antihydrogen, it would fall up even faster. But I highly doubt it's actually gravitationally repulsive.
- smosher 15y agoThe simple solution is to let it fall in a vacuum, which seems to be what they're doing in this case.
- lloeki 15y agoSo 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.
- dadro 15y agoIf 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?
- gecko 15y agoGiven 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.
- goalieca 15y agoNot to mention that it would take a LOT of mass to balance out the weight of the board and the person riding it.
- viraptor 15y agoNot 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.
- simpleTruth 15y agoMeaningful 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.
- enko 15y ago> 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".
- ljf 15y agoSo who is bootstrapping the first startup right now to make hoverboards?
- civilian 15y agoYou'll need a lot of bootstrapping for hoverboards. (teehee)
- Tuna-Fish 15y agoAssuming 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.
- jacques_chester 15y agoAntimatter 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 explosion.
- vl 15y agoHmm, 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.
- Tuna-Fish 15y agoThat "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.)
- Typhon 15y agoBy 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.
- othermaciej 15y agoI'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.
- aufreak3 15y agoI think the way that is usually phrased is that "photons are their own antiparticles". Rgd "anti matter galaxies", we do detect particle cosmic rays on earth that originate from outer space (outside the solar system), though I don't know either whether they might originate from as far as other galaxies. However, gravity is weak compared to the other forces, so galaxies can be expected to eject fast moving matter in addition to radiation (just like our sun). So, given my meagre understanding of physics, I wouldn't expect to have seen anti-matter galaxies without also seeing gamma radiation fields spanning the space between a matter and an antimatter galaxy as particles annihilate each other.
- InclinedPlane 15y agoEmpty space isn't completely empty, even between galaxies. There are traces of gas, almost entirely Hydrogen, between galaxies. If there were entire galaxies made of anti-matter then the areas where their clouds of inter-galactic anti-gas contacted normal inter-galactic gas would be rife with emissions due to annihilations. The amount of matter should be enough to be detectable even at tremendous distances.
- 15y ago
- wazoox 15y agoOoooh, if antimatter is repelled by gravity, that means that cavorite actually is antimatter, and therefore possible? I've always thought that cavorite is the cleverest Science Fiction device ever imagined...
- Apocryphon 15y agoThey called it the greatest discovery in human history. The civilizations of the galaxy call it... MASS EFFECT.
- mmaunder 15y agoThis is super exciting. One day when I'm wealthier than God I'm going to donate some money to the guys who are trying to find him.