Scientists at the Geneva-based CERN research center announced Wednesday that they're yet another step closer to proving that dark matter—the unseen stuff that they believe makes up a quarter of the universe—actually exists. And, yes, you can thank Congress for paying to strap a magic bus to the side of a Space Shuttle and help us understand what we're doing here.
An international team of scientists collected data on over 25 billion recorded events and monitored the excess production of roughly 400,000 positrons, the antimatter form of electrons, using the Alpha Magnetic Spectrometer, a device mounted on the top of the International Space Station. You see, dark matter theoretically expels positrons that are destroyed after colliding in a burst of energy. The data shows sharp increases in the positron fraction in the range of 10 billion to 250 billion electron volts, with no variations in time or 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," the team said in a statement. The detection of dark matter isn't the only answer shown in the data, though. There are alternative theories the evidence supports that have nothing to do with dark matter. We'll let the folks from MIT explain:
However, the AMS measurement cannot yet rule out the alternative explanation that the positrons originate from pulsars distributed around the galactic plane. Supersymmetry theories also predict a cutoff at higher energies above the mass range of dark matter particles, and this has not yet been observed.
That would be a bummer. CERN scientists have to keep collecting data and crunching some numbers, even though this is the largest collection of antimatter data from space ever, but for now they're pretty sure they're on the right track.