NASA Finds New Clue Into Origin of Mysterious Deep Space Signals

The reason for a strange burst of radio waves that came from deep space may have become closer to being revealed, according to new NASA research.

These fast radio bursts can release as much energy in a fraction of a second as the sun does in an entire year, baffling scientists as to what causes these outbursts.

Now, two NASA X-ray telescopes watched a fast radio burst occur in real-time within our own galaxy, observing the minutes before and after the event in 2022, according to a new paper in the journal Nature. Their findings may provide more clues as to what causes fast radio bursts to be released.

"We've unquestionably observed something important for our understanding of fast radio bursts," study author George Younes, a researcher at Goddard and a member of the NICER science team, said in a NASA statement.

The burst of energy came from a magnetar, which is a rare type of neutron star. Neutron stars are the extremely dense core left behind after a massive star undergoes a supernova explosion, but magnetars are a special kind with incredibly strong magnetic fields, billions of times stronger than those of typical neutron stars and trillions of times stronger than the Earth's magnetic field. Only around 30 of these magnetars have been discovered so far.

The fast radio burst described in the paper came from a magnetar named SGR 1935+2154, a 12-mile-across object about 30,000 light years away, which had been previously spotted to release a fast radio burst in 2020. The 2020 burst was the first time that a fast radio burst had been seen in our own galaxy, with all previous observations occurring in other galaxies, much too far away for astronomers to see where they came from.

Now, the new paper reveals more about how magnetar SGR 1935+2154 releases these fast radio bursts. The researchers observed the burst using NASA's NICER (Neutron Star Interior Composition Explorer) on the International Space Station and NuSTAR (Nuclear Spectroscopic Telescope Array) and described what happened on the surface of the magnetar and its immediate surroundings both before and after the burst.

The fast radio burst was observed between two "glitches," which were when the magnetar suddenly started spinning faster. The magnetar usually spins about 3.2 times per second, rotating at a speed of around 7,000 miles per hour, meaning that any increase or decrease in its speed needs a huge amount of energy. Surprisingly, between the glitches, it slowed back down to its original speed in only nine hours—100 times faster than has ever been seen in a magnetar before.

"The key discovery of this research is identifying two glitches happening within a remarkable short period of approximately 9 hours," study co-author Chin-Ping Hu, an astrophysicist at the National Changhua University of Education in Taiwan, told Newsweek.

"In this 9-hour interval between the glitches, the magnetar exhibited the largest spin-down rate ever recorded from a neutron star, accompanied by intense activity, including a storm of short X-ray bursts, a mini flare lasting less than a day, changes in the X-ray spectrum, and a fast radio burst."

Additionally, they found that before the 2022 fast radio burst, the magnetar started giving off powerful X-rays and gamma rays.

"All those X-ray bursts that happened before this glitch would have had, in principle, enough energy to create a fast radio burst, but they didn't," study co-author Zorawar Wadiasingh, a research scientist at the University of Maryland, College Park and NASA's Goddard Space Flight Center, said. "So it seems like something changed during the slowdown period, creating the right set of conditions."

The scientists still don't know exactly what triggered the fast radio burst but think that perhaps the structure of the magnetar might come into play. The exterior of the object is solid and crushes the interior into a superfluid material under the intense stresses of the magnetar's gravity.

Like water sloshing in a bowl, if the two get out of sync as they spin, huge amounts of energy might crash into the side of the exterior, causing a glitch, and could even crack the surface, causing the rapid slowing down as fluid leaks out into space.

Despite this new discovery, they still don't truly know what triggers a fast radio burst.

"Fast radio bursts are intense and coherent radio emission. Therefore, it is believed that FRBs originate from environments with strong magnetic fields," Hu said. "The activity of magnetars stands as a leading candidate for triggering FRBs. Nonetheless, the detailed mechanisms behind this process require further investigation."

"This study highlights the importance of high-cadence observations in unveiling the nature of transient phenomena, which in turn advance our understanding of poorly known properties of magnetars and neutron stars in general such as their interiors and the dynamics leading to the emission of fast radio bursts," Hu added.

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Update 2/20/2024, 12:58 p.m. ET: This article was updated with comment from Chin-Ping Hu.