Hints of Dark Matter Possibly Seen in Experiment: Three Clues to Mysterious Material

Scientists may have discovered hints of dark matter, the elusive material that makes up about 27 percent of the universe, at an underground laboratory in the United States. True to its name, the mysterious substance has never been seen.

Despite their findings, though, the scientists are cautious about announcing that they've actually found dark matter. "We're not claiming anything," said Blas Cabrera, a Stanford University physicist at the meeting of the American Physical Society, in an interview with Space.com.

That said, the scientists did show three promising clues to it from the Super Cyrogenic Dark Matter Search (SuperCDMS), which takes place deep underground in the Soudan mine in northern Minnesota. There, the researchers attempt to catch the interaction between dark matter and normal matter, currently believed to be a very rare occurrence, according to BBC News. More specifically, they watch for dark matter particles bumping into the nuclei of atoms in a detector that is held at temperatures near absolute zero (minus 459.67 degrees Fahrenheit). This chilled environment is ideal for directly detecting these particles since if one passes through and hits a frigid atom nucleus, it will release a charge and heat that scientists can then detect.

Detecting these particles isn't easy, though. In 2010, scientists reported two potential dark matter sightings, but it turned out that the readings came from the instrument rather than any actual particles. Billions of dollars have been spent in search of dark matter since the 1930s, but so far there have been no hard leads, according to NBC News.

Now, though, the researchers have announced the occurrence of three high-energy events, which were originally recorded in 2008. The interactions witnessed point to the existence of dark matter with a best-guess mass of about 8.6 billion electron volts--that's about nine times as large as the proton. In all, the scientists calculated that there should be .7 events of that type on average recorded during the time frame for the readings.

There is a chance that these findings are a fluke, but researchers believe that there's a 99.8 percent chance that their results reflect a real phenomenon.

"Given the money involved--$30 million in this case--it has to be extremely precise," said Rupak Mahapatra, a physicist at Texas A&M University, in an interview with NBC News. "With a 99.8 percent chance, that means if you repeated the same experiment a few hundred times, there is one chance it can go wrong. We want one out of a million instead."

Although it's too early to claim a discovery, the findings could mean some interesting truths if they're found to be true. In particular, the heavier particle mass of dark matter could explain why it makes up so much more of the universe than ordinary matter.

Currently, the researchers are hot on the trail of dark matter, and will continue to search for its existence.