Slashdot Mirror
Antimatter Atoms Captured
Whamo writes: "Researchers at CERN think they have created and stored thousands of antiatoms in a particle trap. The researchers first used powerful magnetic fields to trap antiprotons then exposed this to a beam of positrons. Initial results indicate that at least some of the antiparticles have bound together to become neutral antihydrogen atoms. How cool is that?"
The idea is that if you have a hydrogen and an anti-hydrogen meet, there will be a huge explosion of energy. Stephen Hawking jokes that if you ever meet the "anti"-you, don't shake hands.
Joe
I know that the dept tag is supposed to be funny, but the real benefit of this research is insight into very powerful propulsion systems. No? Not very sustainable at our current rate but definitely the next step toward reaching deeply into space.
Of course, anti-matter engines are waaaaaaaay off, but I think that we should see from the next-stop-Crab-Nebula dept. rather than from the I-frag-way-too-much dept.
Comparing it to Windows will be a moot point, since El Dorado is going to have a 40% larger code base than XP.
Yummy on Cheerios.
Best Slashdot Co
To double-check this, they're going to run the experiment again, and do a spectral analysis of what they've got in the particle trap later this year. I guess they've already got a theory on how the spectral emission/absorption lines of anti-hydrogen will compare to those of hydrogen.
Chris Beckenbach
The mass of an antihydrogen atom is roughly 1e-27 kilograms, the same as a hydrogen atom. Using Einstein's famous formula, with the speed of light given as 3e+8 meters/second, the annihilation of one anti-hydrogen atom and one hydrogen atom would produce 2*(1e-27)*(3e+8)^2 = 1.8e-10 joules. The specific heat capacity of water is 4.2 J/(g*K), so 1.8e-10 joules would raise a 300g cup of coffee by 1.4e-13 degrees Kelvin. (I haven't had my coffee yet ... does that sound right? Anyone?)
The point is, one hydrogen atom makes little difference, but annihilating kilogram's worth of hydrogen atoms would liberate 9,000 terajoules of energy. Compare that to a kilogram of coal, wood, or oil ...
Toronto-area transit rider? Rate your ride.
A water bottle full of anti water (assuming the bottle had an outer shell of normal matter, with perhaps magnetic coils or something to keep an inner cylinder of antimatter containing the matter), when drunk (actually you'd never taste it or see anything after you opened the lid) would release about 6 megatons of energy, enough to obliterate your whole city.
That should answer your questions. Both antiprotons and positrons (aka antielectrons) are electrically charged. Therefore they are accelerated if you apply an electric field. The antihydrogen atom consists of one antiproton and one antielectron. Since the charge of antiprotons and that of positrons is opposite, the antihydrogen atom has no net electric charge and stays immobile in an electric field. So they guess that, if it doesn't move, it must be an atom! There are of course more elaborate tests one can do, and will do. For example, ordinary hydrogen atoms emit light at very specific frequencies (maybe some of you will remember the terms Lyman series, Balmer series etc. from freshman physics). Since the antihydrogen is the exact "mirror image" of the ordinary hydrogen atom, these frequencies must be the same. Observation of these frequencies should yield definite proof (or reveal it as a flop :-)
Yes.
All the quantum numbers of anti-particles are of the opposite sign as compared with normal matter. These quantum numbers include things such as electric charge, but also baryon and lepton number. Anti-neutrons would have a baryon number of -1 as opposed to neutrons which have a baryon number of +1.
(Physics is not my forte).
:) Right now, the energy required to create and hold the anti-hydrogen exceeds the the energy output of the matter-antimatter reaction. Right now, remember. Similar to how it requires more energy to design and build a car engine than that engine will be producing. But, once you work the bugs out and get that sucker up to speed, the energy created by the matter-anti-matter reaction will far exceed the energy required to hold the reaction. It's just a matter of time...provided the funding to do the research is there. We'll see how Big Oil reacts to this. :)
...so I'll be gentle.
But what does my opinion matter, I just vote here. It's not like I have any money or anything.
About the free electron laser part ... it is well beyond present FEL technology. And the technology you describe would have difficulty making anti-protons.
Suppose you want to create electron-positron pairs via counter-streaming FEL lasers. For the physics buffs out there, the reaction would be similar to the Compton backscattering of light off virtual electron-positron pairs (this non-linear vacuum light interaction was demonstrated at SLAC a year or so ago).
The FEL laser would have to operate well into the hard gamma (photon energy exceeding the rest mass of the electron). Current multi-pass FEL technology has been demonstrated up to the ultraviolet (~250 nm I think is the current record). Multi-pass X-ray FELs are near impossible to make because of the difficulty of producing high quality laser cavities for X-rays.
Single pass X-ray FELs (which rely on an electron beam instability instead of a cavity) have been proposed but not yet demonstrated. If I recall correctly, the SASE-FEL program at SLAC to build a $100M dollar X-Ray SASE-FEL (with a 100m long wiggler) did not receive funding.
That is not to say we are incapable of artifically making hard gamma rays. The aforementioned non-linear light interaction obtained the photons for the experiment by Compton scattering of low energy photons off an ultra-relativistic electron beam. But this would probably be pretty inefficent method to try to create antimatter on a large scale (inefficiencies in electron beam acceleration and cross section issues for both the Compton scattering and the non-linear interaction).
The other possibility would be to try to do a multi-photon interaction to create the electron-positron pairs. In this method, an incredible high electric field is created such that it becomes energetically favorable for electrons-positron pairs to form to shield out the field. I think this has also been demonstrated with some of the extremely high intensity chirped pulse amplification lasers. However, the effectiveness isn't anything to write home about yet.
And given the protons mass is 1836 times that of an electron, to create them on a large scale (i.e. micrograms) is not anything I expect to see in the near future.
Kevin
http://www.fnal.gov/ This is the Fermi National Accelerator Laboratory. They have extensive information on particles, particle physics, and how they collider works in general. A very good read if you really want to find out about gluons, quarks, leptons, and all of their asociated anti-particles. G-der gder@gder.net
Basically, the anti-matter/matter reaction is the most efficent mass to energy conversion there is.
This brings us closer to one of the propulsion systems envisioned by hard science fiction writer and physicist Robert L. Forward in a number of his books, the latest of which is "Indistinguishable From Magic".
http://www.whidbey.com/forward/
His books are prime reading for slashdotters. They are a throwback to the early SF of Campbell and Heinlein, but with much more real science thrown in.
Well see, there's this bit about the positron
not being localized, with a non-uniform
probablity density to boot. So while globally
electrically neutral locally the magnetic
fields do not cancel.
NMR (Nuclear Magnetic Resonance), used in Chemistry and other fields, relies upon
the magnetic properties of certain nuclei
(1H, 13C...) to determine the structure of
an intact molecule.
Were that I say, pancakes?
But the Spock in the alterative universe wasn't really evil (unlike the evil Kirk et. al.). That was the whole point of that episode, in both universes he was neither good nor evil, but logical.
Better to be despised for too anxious apprehensions, than ruined by too confident a security. --Edmund Burke
On second thought, anyone know if matter + antimatter actually does = lots of energy? I thought that they were going to do some kind of experiment with that but I never heard any more.
.005 grammes of antimatter (quite a lot), and mixed it with the equivilant matter, we would be converting .01 grammes (.00001kg) of matter into energy,
Well, if we took
so If we take E=MC^2
Where M=mass(in kg), C=speed of light (3*10^8 m/s)
= 1*10^-5* 3*10^8 * 3*10^8
= 1*10^-5 * 9*10^16
= 9 * 10^11 Joules of energy
Which is enough to light 10,000 100 watt light bulbs for about 10 days