Radio signals are being sent to Earth in a 16-day cycle from a galaxy 500 million light-years away — but no one knows why, or what they mean, according to CBS.

Researchers at the Canadian Hydrogen Intensity Mapping Experiment (CHIME), in conjunction with researchers from the Fast Radio Burst Project, tracked the radio signal for more than a year, CNN reports. The researchers were able to distinguish a pattern: For four days the signal would send a burst of short radio waves called fast radio bursts, or FRBs, then go silent 12 days before starting to send the FRBs again. Their exact findings are detailed in the following paper.

The radio signals are — disappointingly — likely not a message from any extraterrestrial life, MIT clarified in a statement, as the signals are too strong to be produced by anything other than large-scale energetic events.

PHYS reports the cyclical pattern of the signals is likely an indicator that they are coming from some object in orbit of a star — or another large space body — or they are coming from an object that is rotating.

This cycle of FRBs isn’t the only one being transmitted throughout outer space, USA Today reports. According to the Max Planck Institute for Radio Astronomy there are hundreds of these mysterious signals on record, but this recently discovered signal is the closest to Earth out of any of the signals that have been traced.