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nebularain
2002-Dec-05, 08:44 PM
Just thought I'd share this:

http://www.nsf.gov/od/lpa/news/02/pr0288.htm

boron10
2002-Dec-05, 09:16 PM
That is one of the coolest things I have seen in a long time.


Their article describing the results will appear in Physical Review Letters in November.
Has anybody read this? Any more information?

Wiley
2002-Dec-05, 09:44 PM
Very cool indeed. Thanks for the post N. Rain.


On 2002-12-05 16:16, boron10 wrote:
Has anybody read this? Any more information?


At the bottom of the page is a link to the authors' web site (http://hussle.harvard.edu/~atrap/). Their web page contains the letter preprint (http://hussle.harvard.edu/~atrap/Papers/2002/AtrapDrivenHbarProductionPRL.pdf).

nebularain
2002-Dec-06, 12:36 AM
On 2002-12-05 16:44, Wiley wrote:
Very cool indeed. Thanks for the post N. Rain.

You're welcome /phpBB/images/smiles/icon_smile.gif

John Kierein
2002-Dec-06, 12:43 AM
I suspect there's an equal amount of antimatterin the universe as matter.

Chip
2002-Dec-06, 02:03 AM
On 2002-12-05 19:43, John Kierein wrote:
I suspect there's an equal amount of antimatter in the universe as matter.

Hi,
Where do you think it is? Its a big universe of course, but how would we detect antimatter out there?
/phpBB/images/smiles/icon_wink.gif

Ilya
2002-Dec-06, 03:38 AM
Where do you think it is? Its a big universe of course, but how would we detect antimatter out there?
/phpBB/images/smiles/icon_wink.gif


Wherever it comes close to matter, gamma radiation at very specific wavelengths arises.

Chip
2002-Dec-06, 07:55 AM
On 2002-12-05 22:38, Ilya wrote:
Wherever it comes close to matter, gamma radiation at very specific wavelengths arises.

Ah, you mean like this?
http://antwrp.gsfc.nasa.gov/apod/ap970501.html

Glom
2002-Dec-06, 07:48 PM
If the laws of conservation of lepton and baryon number hold, there must be equal proportions of matter and antimatter. Perhaps they occupy sectors of the universe. After all, if a gamma ray decays into an electron-positron pair. One will be thrown out one side and the other will be thrown out in the opposite direction. That idea is super sweet!

If they are confined to sectors, we won't be able to know about it, because the energy levels in a hydrogen atom should be the same as the energy levels in an anti-hydrogen atom so the spectra would be the same.

Possibly the sectors interact at fringes. Was it ever postulated that gamma ray bursters were actually the result of contact between matter and antimatter sectors of the cosmos?

On a related note, on Thursday, I went to University College London for an interview and they showed us the only working positronium generator in the world. Positronium is apparently an atom made up of an electron and a positron in a binary orbit of each other. I also read something in the New Scientist about element number 0, tetroneutronium, or something like that, which is made up of four neutrons.

Scientists are coming up with all sorts of stuff these days.

daver
2002-Dec-06, 10:17 PM
On 2002-12-06 14:48, Glom wrote:
If the laws of conservation of lepton and baryon number hold, there must be equal proportions of matter and antimatter.


Black holes don't conserve baryon number. If you could come up with some mechanism that would preferentially suck antimatter into a black hole you could explain the disparity.

Maybe if you could get some sort of an uneven distribution from the big bang you might be able to explain the disparity.

JS Princeton
2002-Dec-07, 03:52 AM
Well, we know that there is CP and CPT violations going on. Theoreticians can calculate from first principles the anisotropy due to these violations. This gives us a very, very, very slight anisotropy in the amount of baryons as opposed to antibaryons. The energy density of the universe works out observationally so that the baryon/anti-baryon annihilation creating the CMB photons is exactly what you would expect given the present amount of matter we see (assuming no anti-matter) and the present amount of CMB photons. Surprise, the Big Bang solves another problem!

jkmccrann
2005-Oct-21, 11:32 AM
Interesting to hear about an element 0, what's that going to do to all the periodic tables out there?

The Supreme Canuck
2005-Oct-21, 02:41 PM
Er, element 0? What is that exactly? Neutronium?

ToSeek
2005-Oct-21, 03:12 PM
I think we're talking more like element -1 here.

The Supreme Canuck
2005-Oct-21, 06:17 PM
Oh. Strangely, as confusing as that is, it makes a bit of sense. Thanks ToSeek.

publiusr
2005-Oct-21, 07:30 PM
Er, element 0? What is that exactly? Neutronium?

The tetraneutron

The Supreme Canuck
2005-Oct-21, 07:45 PM
Yep. A (possibly) stable isotope of neutronium.