Usually, if you spot a pulsing object, your first instinct would be to identify it as a pulsar. Scientists Discover Farthest, Brightest Pulsar.It’s called GPM J1839–10, and we don’t know what it is.

It blinks about once every 21 minutes, and according to archival data, it’s been doing that at least since 1988. But scientists recently discovered one particular source of flashing light has already proven especially puzzling. There’s actually a fair few types of objects that do this. Like a ticking-or, rather, flashing-clock, some energy sources in the universe hit us with beam after beam of photons, lighting up and darkening on a very set schedule.

Some flash in a large explosion, never to be seen again.

Some beam with the light of other sources. Some things in the universe shine with a constant, life-sustaining light.

It doesn’t nicely fit the description of any of the pulsating space objects we know of, so researchers are still trying to figure out what this object might be.

It pulses at a rate of about once every 21 minutes, and has been doing so since at least 1988.

Scientists have discovered a mysterious pulsating light-and they don’t know what it could be.

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