The uncertainty of science: Using archival data, scientists have discovered a previously undetected but very strange slowly pulsing object that has been doing so since 1988.

Astronomers have found an ultra-slow, long-lasting source of radio-wave pulses, and they are perplexed as to its true nature. While “regular” radio pulsars have very short periods, from seconds down to just a few milliseconds, this source emits a brief pulse of radio waves about three times per hour. What’s more, it has been doing this for decades. “I do not think we can say yet what this object is,” says Victoria Kaspi (McGill University), a pulsar researcher who was not involved in the new study.

Natasha Hurley-Walker (Curtin University, Australia) and her colleagues discovered the mysterious source in data from the Murchison Widefield Array (MWA) observatory in Western Australia. They carried out follow-up observations with the MWA and with other radio observatories in Australia and South Africa. Known as GPM J1839-10, the tardy blinker is located at a distance of some 18,500 light-years away in the constellation Scutum. Archival data from the Very Large Array in New Mexico and the Indian Giant Metrewave Radio Telescope reveal that it has been pulsating at least since 1988, with a period of just under 22 minutes (1,318.1957 seconds, to be precise).

In a sense, the object is a pulsar, since on a very basic level it does what all pulsars do, send a radio beat in our direction in a precise pattern. The problem is that according to present theories that say pulsars are actually magnetized neutron stars rotating quickly, this object is rotating too slowly to be one.