Possible evidence of dark matter found
GENEVA — It is one of the cosmos' most mysterious unsolved cases: dark matter. It is supposedly what holds the universe together. We can't see it, but scientists are pretty sure it's out there.
Led by a dogged, Nobel Prize-winning gumshoe who has spent 18 years on the case, scientists put a $2 billion detector aboard the International Space Station to try to track down the stuff. And after two years, the first evidence came in Wednesday: tantalizing cosmic footprints that seem to have been left by dark matter.
But the evidence isn't enough to declare the case closed. The footprints could have come from another, more conventional suspect: a pulsar, or a rotating, radiation-emitting star.
The Sam Spade in the investigation, physicist and Nobel laureate Sam Ting of the Massachusetts Institute of Technology, said he expects a more definitive answer in a matter of months. He confidently promised: “There is no question we're going to solve this problem.”
“It's a tantalizing hint,” said California Institute of Technology physicist Sean Carroll, who was not part of the team. “It's a sign of something.” But he can't quite say what that something is. It doesn't eliminate the other suspect, pulsars, he added.
The results from the Alpha Magnetic Spectrometer, or AMS, are significant because dark matter is thought to make up about a quarter of all the matter in the universe.
“We live in a sea of dark matter,” said Michael Salamon, who runs the AMS program for the Energy Department. Unraveling the mystery of dark matter could help scientists better understand the composition of our universe and, more particularly, what holds galaxies together.
Ting announced the findings in Geneva at the European Organization for Nuclear Research, the particle physics laboratory known as CERN.
The 7-ton detector with a 3-foot magnet ring at its core was sent into space in 2011 in a shuttle mission commanded by astronaut Mark Kelly while his wife, then-Rep. Gabrielle Giffords, was recovering from a gunshot wound to the head. The device is transmitting its data to CERN, where it is being analyzed.
For 80 years scientists have theorized the existence of dark matter but have never actually observed it directly. They have looked for it in accelerators that smash particles together at high speed. No luck. They've looked deep underground with special detectors. Again no luck.
Then there's a third way: looking in space for the results of rare dark matter collisions. If particles of dark matter crash and annihilate each other, they should leave a footprint of positrons — the anti-matter version of electrons — at high energy levels. That's what Ting and AMS are looking for.
They found some. But they could also be signs of pulsars, Ting and others concede. What's key is the curve of the plot of those positrons. If the curve is one shape, it points to dark matter. If it's another, it points to pulsars. Ting said they should know the curve — and the suspect — soon.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Comets hold life building blocks
- Vibrantly colored mural spread across 200 homes in central Mexico city
- Al-Qaida branch in Syria threatens U.S.-backed forces
- Zimbabwe suspends hunts amid outcry over lion’s death
- Talks fail to yield accord in Pacific
- Taliban fracture outcome unclear
- Bin Laden relatives among crash casualties
- Al-Qaida group in Syria targeted by U.S.-led coalition airstrikes
- Senate to grill United Nations agency chief Amano on Iran nuclear pact
- Syria’s embattled President Assad admits manpower shortage
- Saudis’ deadly airstrikes resume in Yemen