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Dark Matter discovery

by DiracPool
Tags: dark, discovery, matter
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DiracPool
#1
Feb18-13, 03:24 PM
P: 580
Anybody have any insight on what this is all about? Looks interesting...

http://news.yahoo.com/dark-matter-fi...144840916.html
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Naty1
#2
Feb18-13, 03:39 PM
P: 5,632
I can conjure up a lot of questions, no answers:
from the article:
Another telling sign will be the question of whether positrons appear to be coming from one direction in space, or from all around. If they're from dark matter, scientists expect them to be spread evenly through space, but if they're created by some normal astrophysical process, such as a star explosion, then they would originate in a single direction.
This part sounds more reasonable:
The Alpha Magnetic Spectrometer has the potential to detect the positrons and electrons produced by dark matter annihilations in the Milky Way.

I thought galaxies coalesced around dark matter.....so wouldn't we expect positron concentrations from the direction of nearby galaxies??
DiracPool
#3
Feb18-13, 03:54 PM
P: 580
Quote Quote by Naty1 View Post
I thought galaxies coalesced around dark matter.....so wouldn't we expect positron concentrations from the direction of nearby galaxies??
I don't know. What I think is strange is that they spent 2 billion dollars on this AMS bus and it almost didn't make it into space. That would have been a waste.

Mordred
#4
Feb18-13, 04:34 PM
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Dark Matter discovery

Should be interesting but without more info difficult to conjecture what they found.
Drakkith
#5
Feb18-13, 05:49 PM
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Quote Quote by Naty1 View Post
I thought galaxies coalesced around dark matter.....so wouldn't we expect positron concentrations from the direction of nearby galaxies??
Dark matter is thought to form a large spherical halo around our galaxy, so we would be detecting the positrons coming from all directions because of this. At least, that's what I get out of it.
marcus
#6
Feb18-13, 06:00 PM
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Quote Quote by DiracPool View Post
Anybody have any insight on what this is all about? Looks interesting...

http://news.yahoo.com/dark-matter-fi...144840916.html
Good find! I've found Michael Turner (a top cosmologist and U of Chic. prof) to be highly reliable. Been paying attention to what he says for around 10 years now. He says to expect a DM particle to be discovered. The 2010s he thinks are going to be the "decade of the WIMP".

DM clouds have already been mapped by their gravitational distortion of the images coming thru them. Irregular-shaped contour maps showing regions of different densities of DM cloud. You may have seen these maps. It's already pretty credible, but they just haven't got their hands on the particle yet.

This AMS detector will help, if it finds some suggestion of a positron spike at a certain energy. Also if more positrons of that energy are coming from a broad region around the center of the galaxy (where more DM is expected to have collected.)

Also several new extensions of the Standard matter model have candidate DM particles, so any favorable observations will set off a lot of excitement and turmoil amongst the model-builders.

Three authors Stephon Alexander, Antonino Marciano, Lee Smolin have recently developed a very interesting model that not only gives rise to a DM particle but also to a Higgs and also manages to unify matter and gravity! It brings together General Relativity and Quantum Mechanics in such a fashion that the Standard Model of matter seems comfortable with guantum space-time geometry. Alexander is talking about the new model Tuesday 26 February, in about a week, in an online seminar.

And that is only ONE of the rival models that unify gravity with the other interactions.

So maybe the Twenty-teens will be the "decade of the WIMP" as Michael Turner was quoted as saying.

Thanks for spotting that news item and sharing it.
marcus
#7
Feb18-13, 06:06 PM
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Naty, if we go by the article they are hoping to detect POSITRONS from DM decay. A positron (being anti-matter) would not be able to travel very far without running into something and getting annihilated, I think. I think the best we could hope for is detecting decay products from concentrations of DM in and around our own galaxy.

It might in fact all be so short range that there would be no directionality at all. I don't know enough to judge that. Just have to guess and/or wait for the announcement.

Here's a BBC item with a lot of overlap with the Yahoo one in the initial post.
http://www.bbc.co.uk/news/science-environment-21495800
It does have a diagram of the Spectrometer instrument.
Vanadium 50
#8
Feb18-13, 06:28 PM
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Sorry, but we don't discuss speculation, rumor and non-public results. When it's announced, we can reopen this.


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