A mysterious interstellar radio signal has been blinking on and off every 22 minutes for more than 30 years

Final 12 months, we made an intriguing discovery—a radio sign in space that switched on and off each 18 minutes.

Astronomers anticipate to see some repeating radio indicators in space, however they normally blink on and off far more shortly. The most typical repeating indicators come from pulsars, rotating neutron stars that emit energetic beams like lighthouses, inflicting them to blink on and off as they rotate in the direction of and away from the Earth.

Pulsars decelerate as they grow old, and their pulses turn into fainter, till finally they cease producing radio waves altogether. Our unusually gradual pulsar might greatest be defined as a magnetar—a pulsar with exceedingly advanced and highly effective magnetic fields that might generate radio waves for a number of months earlier than stopping.

Sadly, we detected the supply utilizing knowledge gathered in 2018. By the point we analyzed the information and found what we thought is perhaps a magnetar it was 2020, and it was now not producing radio waves. With out further knowledge, we had been unable to check our magnetar concept.

Nothing new beneath the sun

Our universe is huge, and to this point each new phenomenon we have found has not been distinctive. We knew that if we regarded once more, with well-designed observations, we had an excellent probability of discovering one other long-period radio supply.

So, we used the Murchison Widefield Array radio telescope in Western Australia to scan our Milky Way galaxy each three nights for a number of months.

We did not want to attend lengthy. Nearly as quickly as we began wanting, we discovered a brand new supply, in a special a part of the sky, this time repeating each 22 minutes.

Finally, the second we had been ready for. We used each telescope we might discover, throughout radio, X-ray, and optical mild, making as many observations as doable, assuming it could not be lively for lengthy. The pulses lasted 5 minutes every, with gaps of 17 minutes between. Our object regarded quite a bit like a pulsar, however spinning 1,000 instances slower.

Hiding in plain sight

The true shock got here after we searched the oldest radio observations of this a part of the sky. The Very Giant Array in New Mexico, United States, has the longest-running archive of knowledge. We discovered pulses from the supply in knowledge from yearly we regarded—the oldest one in an commentary made in 1988.

Observing over three a long time meant we might exactly time the pulses. The supply is producing them like clockwork, each 1,318.1957 seconds, give or take a tenth of a millisecond.

Based on our present theories, for the supply to be producing radio waves, it ought to be slowing down. However in line with the observations, it isn’t.

In our article in Nature, we present that the supply lies “under the dying line,” which is the theoretical restrict of how neutron stars generate radio waves; this holds even for fairly advanced magnetic area fashions. Not solely that, but when the supply is a magnetar, the radio emission ought to solely be seen for a number of months to years—not 33 years and counting.

So after we tried to resolve one drawback, we by chance created one other. What are these mysterious repeating radio sources?

What about ET?

After all, it’s extremely tempting at this level to achieve to extraterrestrial intelligence as an choice. The identical factor occurred when pulsars had been found: astrophysicist Jocelyn Bell Burnell and her colleagues, who discovered the primary pulsar, nicknamed it “LGM 1,” for “Little Inexperienced Males 1.”

However as quickly as Bell and her colleagues made additional detections, they knew it couldn’t be aliens. It could be extremely unlikely for therefore many comparable indicators to be coming from so many various elements of the sky.

The pulses, just like these of our supply, contained no data, simply “noise” throughout all frequencies, identical to pure radio sources. Additionally, the energy requirements to emit a sign in any respect frequencies are staggering: you’ll want to use, properly, a neutron star.

Whereas it is tempting to attempt to clarify a brand new phenomenon this fashion, it is a bit of a cop out. It would not encourage us to maintain considering, observing and testing new concepts. I name it the “aliens of the gaps” strategy.

Fortuitously, this supply continues to be lively, so anybody on this planet can observe it. Maybe with artistic follow-up observations, and extra evaluation, we’ll have the ability to clear up this new cosmic thriller.

This text is republished from The Conversation beneath a Inventive Commons license. Learn the original article.