Although we know that dark matter exists, as of yet, we still understand little about it. Now, a particle detector called the Alpha Magnetic Spectrometer (AMS) on the International Space Station (ISS) could shed more light on the elusive substance by finding an excess of positrons that could be the result of dark matter collisions.

Dark matter is matter that neither emits or absorbs light, making it invisible to telescopes. We only know it exists due to its gravitational effects on matter we can see. Dark matter makes up over 80 percent of the Universe, yet we still haven't successfully detected it.

However, researchers at MIT's Laboratory for Nuclear Science recently released measurements taken by the AMS that suggests that the particle detector could have actually detected dark matter.

After analyzing over 40 billion cosmic rays that entered the detector, physicists determined that among those particles, there was a much higher amount of positrons than expected.

It's natural that positrons, as well as electrons, occur when particles are exposed to cosmic rays, but the increased number of positrons detected by AMS suggests that the excess could come from an as-of-yet unexplained new source. That source could be the result of collisions between dark matter particles. These collisions are so violent that they destroy the particles involved, which releases energy as other particles. Because positrons are the rarest of visible matter particles, an excess could mean that they are the result of such collisions.

Of course, these positrons could also be the result of pulsars, which emit beams of electromagnetic radiation that also result in an excess of these particles. However, the MIT team hope to rule that possibility out.

"We do not know yet if these positrons are coming from dark matter collisions, or from astrophysical sources such as pulsars," says Paolo Zuccon, an assistant professor of physics at MIT. "But measurements are underway by AMS that may discriminate between the two hypotheses."

If these positrons are the result of dark matter, it could change what we know about the substance. These results might suggest that dark matter is actually a particle that we're currently unfamiliar with. Regardless, though, the data from the AMS could still point to a major scientific discovery.

"The new phenomena could be evidence for the long-sought dark matter in the universe, or it could be due to some other equally exciting new science," says Barry Barish, a professor of physics at the California Institute of Technology. "In either case, the observation in itself is what is exciting; the scientific explanation will come with further experimentation."

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