What triggered the curiosity alarm in this now-known case is that scientists have noticed the existence of a pattern in a series of signals that arrive from a single source half a million light years from Earth.
The researchers detected a pattern in the signal received that happens every 16.35 days. For four days, the signal emits a burst or two every hour. Then, writes CNN, it goes back to silence for another 12 days. This repeating signal has been identified as originating in a massive spiral galaxy. Scientists believe that by detecting the source of the signal they can determine the cause.
The possible explanations for this case, at this point, is that the signal is from the orbital motion of a star, or a neutron star.