Space News: NASA Finds Details about Strange Space Signals

Space News: NASA Finds Details about Strange Signals

Have you ever heard of fast radio bursts? They're these fascinating pulses of radio waves that come from way out in space. Scientists have been studying them for a while, and they're still a bit of a mystery. The thing is, these bursts are incredibly powerful and brief, which makes it really hard to figure out where they're coming from. But in recent years, astronomers have made some big strides in understanding these strange bursts, and they're getting closer to figuring out their true origins.

In 2020, a fast radio burst – originating from a magnetar – was detected in Earth's home galaxy. Magnetars are the collapsed remains of exploded stars that are extremely dense objects. In October 2022, the same magnetar, known as SGR 1935+2154, produced another fast radio burst that was studied by NASA's NICER and NuSTAR telescopes. These telescopes observed the magnetar before and after the burst and caught a glimpse of what happened on the surface of the source object and in its immediate surroundings.

The burst occurred between two "glitches," when the magnetar suddenly started spinning faster. SGR 1935+2154 is estimated to be about 12 miles (20 kilometers) across and spinning about 3.2 times per second, meaning its surface was moving at about 7,000 mph (11,000 kph). The magnetar slowed down to less than its pre-glitch speed in just nine hours, surprising study authors, as typically, it takes the magnetar weeks or months to get back to its normal speed.

Scientists have a lot of variables to consider when trying to piece together exactly how magnetars produce fast radio bursts. For example, magnetars are so dense that a teaspoon of their material would weigh about a billion (that is a lot!) tons on Earth. The strong gravity means the surface of a magnetar is a volatile place, regularly releasing bursts of X-rays and higher-energy light. Before the fast radio burst in 2022, the magnetar started releasing eruptions of X-rays and gamma rays observed in the peripheral vision of high-energy space telescopes. The paper authors think that the exterior of a magnetar is solid, and the high density crushes the interior into a superfluid state. Occasionally, the two can get out of sync, like water sloshing around inside a spinning fishbowl. When this happens, the fluid can deliver energy to the crust. The paper authors think this is likely what caused both glitches that caused the fast radio burst. 

However, having observed only one of these events in real time, the team cannot yet say for sure which of these factors might lead to the production of a fast radio burst. Some might not be connected to the burst at all. Nonetheless, the results from NICER and NuSTAR's observations of the fast radio burst that came from SGR 1935+2154 represent an important step forward in understanding these extreme radio events.