First discovered in 2007, fast radio bursts (FRBs) are invisible to the human eye but can be detected with radio telescopes. They come from beyond our galaxy, traveling billions of light years, and are so powerful that the FRB signal can dwarf the radiation of the entire galaxy they come from.

Despite this power (and the fact that up to 10,000 FRBs can form on Earth every day), their source remains unknown, in part because such bursts last only a thousandth of a second.

FRBs fall into two main categories. Some repeat, some don’t; these make up the vast majority of radio bursts. At the same time, the energy distribution of repeated FRBs is similar to the energy distribution observed in earthquakes. New research from the University of Tokyo has strengthened this similarity and suggested that radio bursts may originate from the seismology of neutron stars.

Neutron stars have an extreme nature similar to FRBs. Powerful stars are born when they exhaust their own fuel supply for nuclear reactions and shed their outer layers in supernova explosions. This remains the stellar core, with a mass between one and two solar masses and a diameter of only 20 kilometers.

This rapid compression has three main consequences. First of all, a substance so dense that the weight of a sugar cube is approximately 1 billion tons is formed. Second, some stellar remnants can spin at up to 700 revolutions per second. Eventually, the star’s superstrong magnetic fields become “compressed,” increasing in strength and creating some of the strongest magnetic fields known in the universe.

Young neutron stars with exceptionally strong magnetic fields are called magnetars and have previously been associated with FRB emission. Astroseismology theory predicts that the surface of a neutron star may experience disturbances similar to earthquakes on Earth. One potential cause of this phenomenon could be the stress that occurs when strong magnetic fields bend.

“Theoretically, the magnetar’s surface could experience energy-releasing disturbances similar to earthquakes on Earth. Recent observations have led to a collection of thousands of FRBs, and we took the opportunity to compare large-scale FRB statistics with data from earthquakes and solar flares to investigate possible similarities.” team members.

Using the same method used to analyze the time-energy correlation of earthquakes and solar flares, the team looked at the timing and energy of radiation from nearly 7,000 repeated radio bursts. The results showed a significant correlation between FRBs and earthquakes, but not between FRBs and solar flares.

The team found four main similarities between FRBs and earthquakes. First, the probability of an individual FRB and earthquake occurring is between 10% and 50%. Second, their frequency decreases over time according to a static function of time. And finally, their speed always remains constant, even if the average number of FRBs varies significantly. At the same time, no correlation was found between the energy of the main emission and the shaking of the star’s surface in both events.

This shows that when shocks and perturbations occur on the surface of neutron stars, they release enormous amounts of energy, which astrophysicists observe as FRBs. To fully confirm this, the team will continue to analyze new FRB data as it becomes available.

“The interior of a neutron star is the densest place in the universe compared to the interior of an atomic nucleus. Neutron star seismology has provided new insights into very high density matter and the fundamental laws of nuclear physics,” said Totani. Source