A fast radio burst from the primordial Universe: generated when the Sun did not exist, it traveled through 80% of cosmic history to reach us.
When fast radio bursts (FBRs) appear, they do so without warning: these transient radio pulses, very short and with very high energy, can appear from any region of space and are difficult to intercept. Now the joint work of the MeerKAT radio telescope in South Africa and the James Webb Space Telescope has made it possible to discover the fast radio burst that traveled the longest to reach us: the flash, called FRB 20240304B, originated when the Universe was only 3 billion years old and traveled for another 10 to reach us, crossing 80% of cosmic history.
As explained in a study on Sciencewhatever the source that generated this specific phenomenon, the distance record is confirmation of how long fast radio bursts can travel, and how they can be useful for probing the regions of space they cross.
Produced when the Sun was not yet there
The MeerKAT radio telescope detected the fast radio burst, while the James Webb served to locate the galaxy from which it came, a young, very small, star-forming galaxy with few metals around it, churning out new stars at very high speeds. The red shift (redshift) of the light from the galaxy, i.e. the stretching of its wavelengths of light caused by the expansion of the Universe, then made it possible to calculate the distance of this source.
«Light left its source long before the Earth or even the Solar System existed. The Earth and Solar System only formed about 4.5 billion years ago, so when this explosion began its journey, there was no Earth, no Sun, and no human life. In fact, the Universe itself was only a few billion years old” explained Themiya Nanayakkara, astrophysicist at the University of Sydney and author of the study.
The fast radio burst just identified is the most distant known of the over 10,000 detected from 2007 to today.
The mystery about the source
Some fast radio bursts could be emitted by magnetars, neutron stars with a very powerful magnetic field, and others by mergers of neutron stars or black holes. Whatever the phenomenon that originated this signal, it will be necessary to understand whether it is an isolated flash or whether it will be a recurring fast radio burst, like others in the past. The discovery, however, seems to suggest that events of this type may have been very common in the distant Universe.
