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Does Anti-Matter exist?


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In reply to an earlier post on Jul 28, 2012 5:07:26 AM PDT
Nova137 says:
I personally love the way Dirac didn't ignore the negative energy solutions to spin 1/2 particle equations. The positive energy solution is the electron. The negative energy solution is the positron (anti-matter particle to the negatively charged electron). A classical mind-set would, typically, ignore negative solutions (when looking for real particles). The quantum world asks the investigator to put that mindset aside. Dirac was able to do that and he discovers anti-matter, at least, mathematically. It was about two years before it was actually experimentally verified.

In reply to an earlier post on Jul 25, 2012 12:43:31 PM PDT
Ehkzu says:
Wikipedia's "accelerating universe" entry briefly summarizes what's known at present, along with the leading explanations.

Simplest is called "dark energy."

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

"Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity..."

--W.B. Yeats, "The Second Coming"

In reply to an earlier post on Jul 25, 2012 11:41:17 AM PDT
The Weasel,

I haven't been following developments. I'm going to check...: In the popular press, this seems still to be the latest: <http://www.dailygalaxy.com/my_weblog/2011/04/antigravity-trumps-dark-energy-for-the-accelerated-expansion-of-the-universe.html> although this is a little newer: <http://news.nationalgeographic.com/news/2012/02/120215-dark-energy-antimatter-physics-alternate-space-science>

Posted on Jul 25, 2012 11:25:36 AM PDT
A. Hughman says:
Astronomy isn't my field of expertise, but from what I can recall the speculation is about the composition of dark energy and dark matter, in addition to anti-gravity, not anti-matter. Anti-matter is easily observable by us, it is essentially normal matter with an opposite charge.

In reply to an earlier post on Jul 25, 2012 11:17:58 AM PDT
The Weasel says:
Charles F. Mielke says:
D. Colasante, et al.,

There has been some speculation, over the last few years, that the accelerating expansion of the Universe may be the result of anti-matter and "anti-gravity."
***
More than just speculation at this point. The speculation is about the composition rather than the existence right? Or am I incorrect?

In reply to an earlier post on Jul 25, 2012 11:17:20 AM PDT
D. Colasante says:
I believe the ALPHA and ATRAP teams at CERN are expecting to obtain a spectral analysis of isolated antihydrogen this year. They just got confirmation that of normal behavior at the microwave end. I believe the next experiment will be to examine antihydrogen's behavior with respect to gravity.

In reply to an earlier post on Jul 25, 2012 11:06:05 AM PDT
D. Colasante, et al.,

There has been some speculation, over the last few years, that the accelerating expansion of the Universe may be the result of anti-matter and "anti-gravity."

In reply to an earlier post on Jul 25, 2012 11:03:54 AM PDT
Ehkzu says:
Speaking as an ambidextrous quasidyslexic...exactamundo.

In reply to an earlier post on Jul 25, 2012 10:56:40 AM PDT
Last edited by the author on Jul 25, 2012 10:56:51 AM PDT
D. Colasante says:
Feynman is famous for such a thought experiment regarding symmetry*. We communicate with beings describing ourselves including references to "left" and "right". Upon an arranged meeting one day, upon the obligatory handshake Feynman warns, if the alien puts out his left hand, watch out! An antimatter being will consider left and right opposite to us.

*Six Not-So-Easy Pieces: Einstein's Relativity, Symmetry, and Space-Time (p. 46)

In reply to an earlier post on Jul 25, 2012 10:32:10 AM PDT
Ehkzu says:
re: dark matter beings

DC, that makes perfect sense. Antimatter beings are a different ballgame, though. Seems like they could exist. Hey, you could write a Romeo & Juliet romance between one of us and one of our antimatter counterparts elsewhere in the multiverse, who become a kind of pen pal/MV-Facebook correspondents, separated by the Montague of our universe vs. the Capulet of theirs, doomed to constantly ask each other "What's the matter?"

Posted on Jul 25, 2012 10:23:02 AM PDT
D. Colasante says:
At any rate, it does not seem there could be dark matter beings as there are no electric forces from which to form molecular bonds nor even atoms. Thus it's diffuse, gravity-only distribution. It is thought that it lacks the strong nuclear force as well, so not even hadrons would develop.

In reply to an earlier post on Jul 25, 2012 8:28:56 AM PDT
Ehkzu says:
I was just checking to see if y'all were awake...

In reply to an earlier post on Jul 25, 2012 7:43:17 AM PDT
And mixing up dark energy, too.

In reply to an earlier post on Jul 25, 2012 6:24:55 AM PDT
Ehkzu, I think you might be mixing up antimatter with dark matter.

In reply to an earlier post on Jul 25, 2012 5:27:10 AM PDT
Where do you get your figure from?

Posted on Jul 25, 2012 1:29:08 AM PDT
Last edited by the author on Jul 25, 2012 8:28:21 AM PDT
Ehkzu says:
Do anti-matter creatures debate whether matter exists? Other bubble universes might be as overwhelmingly composed of antimatter as our is of matter, and in such a universe they might well scoff at the idea of matter.

EDITED to reflect correction.

Posted on Jul 24, 2012 7:25:42 AM PDT
A. Hughman says:
Sure anti-matter is real, there is probably some sitting on your kitchen counter right now. Potassium-40, which is a radioactive isotope of potassium is found in bananas, and upon decay, a proton turns in to a neutron and a positron, sort of like the anti-matter equivalent of an electron, as it has a positive charge instead of negative. That positron is very short lived in the banana though, as it is surrounded by regular matter, and as soon as the positron and an electron come in contact they annihilate and convert to pure energy, using the equation e=mc^2 we can see the energy produced by this reaction will be the mass of the two particles times the speed of light squared. This energy is found from annihilation in the form of light, a high energy photon, gamma radiation is produced.

In reply to an earlier post on Jul 23, 2012 2:03:31 AM PDT
Last edited by the author on Jul 23, 2012 2:07:15 AM PDT
Just for the record, Moore's law applies only in limited spheres. Thus far, there is little reason to believe that it applies to antimatter production.

It takes raw energy to produce it, and energy obeys its own kind of laws. One of those we all know about is E=mc^2.

The sun, for instance, outputs energy at a rate of ~1e+33 ergs/sec. To do this, it converts mass to energy at a rate of 1e+12 grams/sec, or about a million tons per second (1e+6 tons/sec). To make the antimatter out of this energy, using the entire emitted energy of the sun with perfect efficiency gives us one million tons/sec. To fill up NCC-1701's tank for the 8 year round trip to Alpha Centauri therefore requires the total energy output of our sun for ~6 quadrillion years, or about 500,000 times the current age of the universe.

Personally, I think interstellar travel on the Star Trek Plan is going to be tough on the wallet for a while, yet.

In reply to an earlier post on Jul 19, 2012 11:49:59 AM PDT
The Weasel says:
I just want my jet-pack

In reply to an earlier post on Jul 19, 2012 11:38:02 AM PDT
Mr. Vicks,

You _do_ realize that investigators have been assuring us of "fusion power within 10 years" for the last 40 years, don't you?

Posted on Jul 19, 2012 11:31:59 AM PDT
Last edited by the author on Jul 19, 2012 11:35:39 AM PDT
D. Vicks says:
I am sure that in 50-75 years anti-matter will be able to be produced easier.

And Fusion power reacters will brake even about 2020.

OT:We need rain.

In reply to an earlier post on Jul 19, 2012 9:06:36 AM PDT
Last edited by the author on Jul 19, 2012 9:07:33 AM PDT
Which is why antimatter is ideal, since the output of the reaction is all photons. Pure momentum.

In reply to an earlier post on Jul 18, 2012 11:01:16 PM PDT
Re Rev. Otter, 7-18 11:31 AM: "sea water would be cheap and plentiful enough to use as reaction mass." Indeed it would, if it were suitable -- but it isn't. If you are building a vehicle using a fusion reactor because you want a huge Isp, you need to have the mass of the ejected particles be as low as possible, because you want the exhaust velocity to be as high as possible -- and the energy required goes as the mass of the particles. Which means that your emitted reaction mass should be alpha particles created by the fusion reaction.

In reply to an earlier post on Jul 18, 2012 10:57:03 PM PDT
Re vicks, 7-18 11:22 AM: "Can Fusion Powered reacters and/or rockets use sea water as fuel?" No. But they can use deuterium, which can be isolated from sea water -- by a costly process.

In reply to an earlier post on Jul 18, 2012 6:24:40 PM PDT
Hamsta says:
Might resemble a floating aquarium?
xD
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Discussion in:  Science forum
Participants:  16
Total posts:  49
Initial post:  Jul 17, 2012
Latest post:  Jul 28, 2012

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