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  ISS Alpha Magnetic Spectrometer: Dark Matter

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Author Topic:   ISS Alpha Magnetic Spectrometer: Dark Matter
SpaceAholic
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Posts: 3023
From: Sierra Vista, Arizona
Registered: Nov 1999

posted 02-18-2013 04:59 PM     Click Here to See the Profile for SpaceAholic   Click Here to Email SpaceAholic     Edit/Delete Message   Reply w/Quote
Space.com is reporting pending release of a paper detailing the results of an ISS onboard experiment which may coo-berate the existence and characteristics of Dark Matter.
Big news in the search for dark matter may be coming in about two weeks, the leader of a space-based particle physics experiment said today (Feb. 17) here at the annual meeting of the American Association for the Advancement of Science.

That's when the first paper of results from the Alpha Magnetic Spectrometer, a particle collector mounted on the outside of the International Space Station, will be submitted to a scientific journal, said MIT physicist Samuel Ting, AMS principle investigator.

Though Ting was coy about just what, exactly, the experiment has found, he said the results bear on the mystery of dark matter, the invisible stuff thought to outnumber regular matter in the universe by a factor of about six to one.

Headshot
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Posts: 182
From: Streamwood, IL USA
Registered: Feb 2012

posted 02-18-2013 05:12 PM     Click Here to See the Profile for Headshot   Click Here to Email Headshot     Edit/Delete Message   Reply w/Quote
Let's hope that Ting's paper will announce a far more substantial discovery than John Grotzinger's overblown "one for the history books" comment about a finding from the Curiosity Mars rover.

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 04-03-2013 12:43 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
CERN release
AMS experiment measures antimatter excess in space

The international team running the Alpha Magnetic Spectrometer (AMS) today announced the first results in its search for dark matter. The results, presented by AMS spokesperson Professor Samuel Ting in a seminar at CERN, are to be published in the journal Physical Review Letters. They report the observation of an excess of positrons in the cosmic ray flux.

The AMS results are based on some 25 billion recorded events, including 400,000 positrons with energies between 0.5 GeV and 350 GeV, recorded over a year and a half. This represents the largest collection of antimatter particles recorded in space. The positron fraction increases from 10 GeV to 250 GeV, with the data showing the slope of the increase reducing by an order of magnitude over the range 20-250 GeV. The data also show no significant variation over time, or any preferred incoming direction. These results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations.

"As the most precise measurement of the cosmic ray positron flux to date, these results show clearly the power and capabilities of the AMS detector," said AMS spokesperson, Samuel Ting. "Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin."

Cosmic rays are charged high-energy particles that permeate space. The AMS experiment, installed on the International Space Station, is designed to study them before they have a chance to interact with the Earth's atmosphere. An excess of antimatter within the cosmic ray flux was first observed around two decades ago. The origin of the excess, however, remains unexplained. One possibility, predicted by a theory known as supersymmetry, is that positrons could be produced when two particles of dark matter collide and annihilate. Assuming an isotropic distribution of dark matter particles, these theories predict the observations made by AMS. However, the AMS measurement can not yet rule out the alternative explanation that the positrons originate from pulsars distributed around the galactic plane. Supersymmetry theories also predict a cut-off at higher energies above the mass range of dark matter particles, and this has not yet been observed. Over the coming years, AMS will further refine the measurement's precision, and clarify the behaviour of the positron fraction at energies above 250 GeV.

"When you take a new precision instrument into a new regime, you tend to see many new results, and we hope this this will be the first of many," said Ting. "AMS is the first experiment to measure to 1% accuracy in space. It is this level of precision that will allow us to tell whether our current positron observation has a Dark Matter or pulsar origin."

Dark matter is one of the most important mysteries of physics today. Accounting for over a quarter of the universe's mass-energy balance, it can be observed indirectly through its interaction with visible matter but has yet to be directly detected. Searches for dark matter are carried out in space-borne experiments such as AMS, as well as on the Earth at the Large Hadron Collider and a range of experiments installed in deep underground laboratories.

"The AMS result is a great example of the complementarity of experiments on Earth and in space," said CERN Director General Rolf Heuer. "Working in tandem, I think we can be confident of a resolution to the dark matter enigma sometime in the next few years."

ASCAN1984
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Posts: 1004
From: County Down, Nothern Ireland
Registered: Feb 2002

posted 04-04-2013 05:59 PM     Click Here to See the Profile for ASCAN1984   Click Here to Email ASCAN1984     Edit/Delete Message   Reply w/Quote
This is amazing but why does it cost $2 billion?

Robert Pearlman
Editor

Posts: 27328
From: Houston, TX
Registered: Nov 1999

posted 04-04-2013 06:36 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
The high cost is a product of several factors, including a long development period (15 years), a large development team (500 scientists from 56 institutions and 16 countries), technical setbacks, and the sheer complexity of the instrument and the endeavor.

All times are CT (US)

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