Samuel Ting, a professor at the Massachusetts Institute of Technology and a Nobel laureate particle physicist, said Wednesday that his $1.6 billion cosmic ray experiment on the International Space Station had found evidence of  “new physical phenomena” that could represent dark matter, the mysterious stuff that serves as the gravitational foundation for galaxies and whose identification would rewrite some of the laws of physics.

The results, he said, 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 comprise electricity and chemistry. They could be colliding particles of dark matter. Or they could be could be coming from previously undiscovered pulsars or other astronomical monsters, throwing off wild winds of radiation.

The tantalizing news is that even with the new data, physicists cannot tell yet which is the right answer, but they are encouraged that they soon might be able to.

“I don’t think it makes you believe it must be dark matter, nor do I think it makes you believe it cannot be,” said Neal Weiner, a particle theorist at New York University.

The good news is that the Alpha Magnetic Spectrometer, as Dr. Ting’s instrument is called, is only two years into what could be a 20-year voyage on the space station, and is working brilliantly. “Over the coming months, A.M.S. will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin,” Dr. Ting told an audience of physicists at CERN, the European Organization for Nuclear Research.