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: "There is no question we're going to solve this problem."
The results from the Alpha Magnetic Spectrometer, or AMS, are significant because dark matter is thought to make up about a quarter of all matter in the universe.
Unraveling the mystery of dark matter could help scientists better understand the composition of our universe and what holds galaxies together.
Ting announced the findings in Geneva at the European Organization for Nuclear Research, a particle physics lab 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 have 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 antimatter 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.