The jury is still out on whether Fermi has spied dark matter.NASA/DOE/International LAT TeamPosted on 07/25/2009 9:27:35 PM PDT by neverdem
Gamma-ray spike in Fermi telescope data hikes anticipation.
The jury is still out on whether Fermi has spied dark matter.NASA/DOE/International LAT TeamThe murky hunt for dark matter has just got a little bit brighter. New gamma-ray results from the FERMI telescope fit with previous tantalizing hints of a detection of the mysterious stuff.
Last year, a series of independent experiments caused a stir because they seemed to have detected signals of dark matter, which is believed to make up 85% of the universe's matter.
"There's been tremendous excitement about cosmic ray signals that have dark matter as one possible explanation," says Neal Weiner at New York University. Specifically, the PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite and the FERMI telescope detected a surplus of high-energy electrons and antielectrons, also called positrons, whizzing through space. The findings were intriguing because such excesses could be produced when dark-matter particles annihilate or decay (see 'Dark matter intrigue deepens').
However, the high energy particles could also have much more mundane origins; for instance, they could have been emitted by pulsars. "An important question is: how are we going to determine whether it's dark matter or some astrophysical source?" Weiner says.
One way to tell is to look for accompanying high-energy gamma-ray photons. All of the dark-matter models that could explain the PAMELA and FERMI data predict that high energy electrons and positrons would smack into ordinary photons in starlight and kick them into the gamma-ray range, says Weiner. The FERMI telescope has been looking for this gamma-ray signal, and last week team member Persis Drell of the SLAC National Accelerator Laboratory in Menlo Park, California, presented results at the TeV Particle Astrophysics conference, held at SLAC, showing that there is a gamma-ray spike at energies around 100 GeV — just where these dark-matter models predict.
Drell presented data for gamma-rays signals at the galactic centre and over a wider region of sky known as the inner galaxy. Weiner's team have now compared the gamma-ray signal from the inner galaxy with predictions made by dark-matter models and found a good match1.
Weiner and his colleagues say that the findings are "certainly exciting". However, Weiner stresses that the results are still perfectly consistent with the possibility that there is no dark matter.
He also emphasizes that the FERMI group presented preliminary data that still need to be cleaned up. He is hopeful that future data from FERMI should clear up any confusion. "As FERMI narrows its field of view, its sensitivity will increase, and there are the prospects for some very important and exciting results," he says.
Piergiorgio Picozza, a PAMELA team member based at the University of Rome Tor Vergata in Italy, agrees that it's too early to draw conclusions. He notes that there has been a string of papers discussing the Fermi and PAMELA results, many of which give conflicting conclusions, and says, "I think that the way towards the truth is still very long."
I wish I could I could say really deep stuff like,
“I think that the way towards the truth is still very long.”
And my intuition tells me when they finally figure it out, there will be an “ether” after all.
parsy
UPDATE: UW Hospital says more than 50 patients may have been exposed to brain disorder
FReepmail me if you want on or off my health and science ping list.
But old woman chaos will surely win the race.
Hot or Cold?
Total collapse, or total disbursement?
Tune in several gigabazillion years later for an update.
My poor attempts at humor aside, what might this “ether” be?
To be or not to be, that is the question!
.......“I think that the way towards the truth is still very long.”.....
Translation...... “We need more money”
But demanding money sounds so crass. Let’s call it “resources”.
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Whoops, and thanks neverdem!
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