Fast radio bursts (FRBs) are extremely powerful energy pulses that originate in the most distant corners of the Universe, but still have no clear scientific explanation. In a millisecond, they can release as much energy as the Sun radiates in three days. What could be their source?
Researchers have put forward many theories to explain this mysterious cosmic phenomenon. One popular hypothesis suggests that FRBs arise from the collision of neutron stars with other neutron stars or even black holes.
Asteroid and neutron star collisions
However, a team of scientists led by Dang Pham of the University of Toronto has proposed a radical new hypothesis. In a study published in the Astrophysical Journal, they suggested that such bursts could be caused by asteroids falling on neutron stars.
According to calculations, the frequency of asteroid collisions with neutron stars coincides with the estimated number of bursts observed in the Universe.
“It’s been known for many years that asteroids and comets impacting neutron stars can cause FRB-like signals, but until now, it was unclear if this happened often enough across the universe to explain the rate at which we observe FRBs occurring,” Pham noted.
Preliminary estimates suggest that there could be as many as ten trillion interstellar objects such as Oumuamua and Comet Borisov in the Milky Way alone. There are about a billion known neutron stars in our Galaxy. Given this data, the team of scientists calculate that one collision occurs every 10 million years per neutron star, which corresponds to the observed frequency of fast radio bursts.
How radio bursts occur
When an asteroid or comet crashes into the magnetic field of a neutron star, it is instantly vaporized and accelerated to near the speed of light. The resulting ball of plasma moves along the magnetic field, creating a beam of radiation that may be the source of the burst.
According to Matthew Hopkins, an astrophysicist at Oxford University, the energy of such bursts depends on the size of the asteroid and the strength of the neutron star’s magnetic field. For example, an asteroid just over a kilometer in diameter could release energy equivalent to 100 million times the energy used by all of humanity in a year.
Unresolved issues
If this hypothesis is correct, the frequency of FRB occurrence may increase with the age of the Universe. Additionally, it should be considered that some fast radio bursts occur repeatedly and at regular intervals in the same source. This is not entirely consistent with the likely nature of collisions between neutron stars and asteroids. Despite this, the collision hypothesis remains an intriguing area for further research as observations and data analysis continue.
We previously reported on how the most distant fastest radio burst would help weigh the Universe.
Provided by Space
