Scientists have picked up a mysterious, energetic and deep radio signal coming from deep in space.
It is not clear where the blast came from, or how it made its way to Earth.
It was detected by researchers at the Canadian Hydrogen Intensity Mapping Experiment, a powerful telescope in British Columbia. The signal was the first to be heard between the frequency of 400 and 800 MHz, making it a much deeper and lower signal than many of those heard before.
Scientists have picked up more than 30 of the fast radio bursts over the last ten years or so. They remain one of the most mysterious phenomena in the universe, and could be a clue to some extreme activity happening billions of light years away.
Since they were discovered in 2007, FRBs have become one of the most mysterious signals in the universe. They are incredibly strong signals that die away intriguingly quickly, and have been seen by telescopes all around the world.
Most of them have also been picked up after the fact. The newly detected burst, which has been given the name FRB 180725A, is rare in that it was seen in real time.
It is difficult to know when they will occur, since there seems to be little pattern to them. Scientists found the first repeating source of FRBs recently, allowing them to keep watch for the signals.
Scientists have long been searching for the source of the bursts, which arrive with great force but last only a tiny amount of time. Scientists have suggested that they are emerging from some kind of "extreme" environment, but nobody has definitively shown where they are being sent from.
That has led to speculation that they could be emerging from a huge undiscovered star, jets emerging from a black hole – or even an artificial source such as alien life.
Researchers last year revealed that they appeared to have tracked the bursts down to a faint dwarf galaxy more than three billion light years away. Before then, scientists had thought that the bursts could be coming from within our own galaxy – but they appear to be arriving from deep within the universe, that research suggested.