Since 1988, the object known as GPM J1839-10 has been blinking every 21 minutes, and scientists have no idea what it is. Flashing lights in outer space are not unusual, but this one does not fit any normal patterns.
Most flashing lights in space are pulsars: neutron stars with magnetic fields that spin rapidly and produce radio beams at their poles. We see the consistent pulse as they spin and the beams hit us, but their pulses are incredibly quick. The fastest pulse every millisecond, and the slowest at about one a minute.
The other kind of neutron star associated with intermittent light from space is a magnetar. These regularly produce fast radio bursts both within and outside our galaxy. But they only produce the pulses for a limited time.
Does not fit any known pattern
The third, and even more ill-fitting option, is that the mysterious light comes from a magnetized white dwarf. White dwarfs are the remnants of long-dead stars. They have exhausted all the hydrogen that stars use as nuclear fuel. Unlike neutron stars, these rotate at a speed that could warrant the 21-minute pulses. The problem is that no one has ever seen them produce bright radio beams before.
The light blinking religiously for 35 years does not fit any of these patterns. The pulses are too far apart for a pulsar and too long-lived for a magnetar. White dwarfs have never produced light in this way before.
Scientists are not yet ready to cast any of the options aside. “This remarkable object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the Universe,” said astronomer and study lead author Natasha Hurley-Walker.
Artist’s impression of a neutron star. Photo: Shutterstock
15,000 light-years away
The study that discovered the object began in January 2022. The team found a “long-period” magnetar. They scoured the skies for something similar and stumbled across GPM J1839-10. It also produced long-lasting radio bursts — five times longer than the original magnetar.
What was even more shocking it that there were observations of this blinking that dated back 35 years.
The discovery of a blinking light that is 15,000 light years away and has been flashing for three-and-a-half decades baffled the team.
“Assuming it’s a magnetar, it shouldn’t be possible for this object to produce radio waves,” said Hurely-Walker. “But we’re seeing them.”
Whatever it is, Hurely-Walker and her research team will keep observing the flashing light. And they will rake through decades of data to try and find anything similar that could solve the mystery.
