We still don't know what's happening on the dark side of the cosmos, but astronomers said Wednesday they might be on the verge of finally finding out what makes up the mysterious dark matter that gives shape to the visible structures of the universe.
Saying the results represented evidence of "new physical phenomena," scientists said a $1.6 billion cosmic ray experiment on the International Space Station had confirmed previous reports that local interstellar space is crackling with an unexplained abundance of high energy particles, especially positrons, the antimatter version of the familiar electrons that constitute electricity and chemistry.
Cosmologists have suggested that decaying dark matter particles would produce such a signal, but so could pulsars, the spinning remnants of dead stars that throw off wild winds of radiation. The disappointing news is that even with the new data, physicists can't tell yet which is the right answer.
The good news is that the Alpha Magnetic Spectrometer, as the instrument is called, is only two years into what could be a 10-year voyage on the space station, and it is working brilliantly. Nobel laureate Samuel Ting of the Massachusetts Institute of Technology, the leader of the spectrometer team, said that in the coming months, the spectrometer "will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin."