Washington (AFP)

Astronomers celebrated Thursday a discovery, published in the prestigious journal Science, which could help them to map the confines of the universe.

A team of international astronomers led by Australian scientists found for the first time the precise origin of a mysterious phenomenon called "rapid radio burst" discovered in 2007.

These cosmic waves can emit in a thousandth of a second the equivalent of 10,000 years of solar energy.

"The entire community of astronomers was eagerly waiting for this result," Casey Law, an astronomer at the University of California at Berkeley, told AFP. He did not participate in the study released Thursday.

This work is the most important since the discovery of these rapid radio surges (FRB, in English). We do not know what produces these monstrous energy murmurs, but astronomers agree on one point: they come from galaxies very, very far away.

The hunt for these bursts has detected 85 since their identification. Most were unique: a flash and then nothing. But a few were repeated.

In 2017, for the first time, astronomers were able to locate precisely the source of a repeated burst, baptized with poetry FRB 121102.

- Map of the cosmos -

But locating a single burst represented another pair of sleeves.

The team, led by Australian Keith Bannister of the Commonwealth Scientific and Industrial Research Organization (CSIRO), has developed a new methodology to meet the challenge.

"You can compare that to a slow motion on TV: we've programmed a computer to actively search for bursts, get a billion measurements per second, and try to find out which ones contain a FRB," says Bannister. AFP.

As a result, the FRB 180924 was discovered by the ASKAP radio telescope in western Australia. He was born 3.6 billion light years from Earth.

The burst has reached each of the thirty-six parabolas of this telescope at an imperceptibly different moment, which allowed the scientists to make a kind of triangulation to calculate the origin.

"It's like looking at the Earth from the moon and finding not only in which house a person lives but also on which chair she is sitting in the dining room," says Keith Bannister.

Thanks to other telescopes in Chile and Hawaii, the scientists were able to get an image of the original galaxy and its distance from the Earth.

While the rapid radio burst located in 2017 came from a dwarf galaxy, the new one described Thursday comes from around a massive galaxy made up of ancient stars.

Which leads the researchers to conclude ... that they still do not know how these bursts are formed.

"This would imply that repeated, unrepeated, rapid radio surges have completely different origins," says Shriharsh Tendulkar, an astronomer at McGill University, who is not a member of the research team.

The discovery fascinates astronomers because it provides new information about what is in the spaces between galaxies ... And could help them solve the enigma of the "missing matter" of the universe.

Scientists have a theory to explain why the number of atoms observed in stars is less than half the theoretical calculations. Missing atoms would be found in ionized gases in intergalactic spaces.

Cosmic waves disperse during their journey to the Earth: a little like light is refracted through a prism.

It turns out that the observations of the team correspond to what theory predicted on the amount of matter lying on its path.

But this will have to be reinforced by thousands, even tens of thousands of additional observations, to form a map of the confines of the universe.

"Like an MRI of the cosmos," says a co-author of the study, Ryan Shannon, of Swinburne University in Australia. As for the missing material, he is optimistic: "It will be enough for us to locate some more bursts to solve the problem".

? 2019 AFP