In July 1967, At the height of the Cold War, American satellites launched to detect Soviet nuclear weapons tests found something completely unexpected. The Vella and s satellites observed brief glows of high-energy radiation photons or gamma rays, which were found to be coming from space. Later, in a 1973 paper compiling more than a dozen mysterious events, astronomers called them gamma-ray explosions. “Since then, we’ve been trying to figure out what these explosions are,” said Andrew Taylor, a physicist at the German Electron Synchrotron (DESY) in Hamburg.

After the initial discovery, astronomers discussed where these explosions of gamma radiation were coming from – an important indication of what was giving them power. Some people thought that such a bright source should be nearby in such a solar system. They argued that they are in our galaxy, but others are outside the universe. Plenty of principles; No information.

Then in 1997, an Italian and Dutch satellite named BeppoXX confirmed that the gamma-ray explosion was extra-galactic, in some cases several billion light-years away.

The discovery was surprising. To keep track of how bright these objects were – astronomers realized that the events that caused them must be almost incredibly powerful. “We thought there was no way you could get as much energy as an explosion from any object in the universe,” said Sylvia Zhou, an astrophysicist from Dysy.

A gamma-ray explosion will emit as much energy as a supernova, which breaks up and explodes, but in seconds or minutes, rather than weeks. Their peak luminosity may be 100 billion times that of our Sun, and even billions of times greater than that of supernovae.

He was lucky that they were so far away. “If a gamma-ray erupts in our galaxy, Jet told us, the best thing you can hope for will soon be gone,” Xu said. Xu said. “You would expect radiation to be broken down by ozone and immediately fry death all the way. Because the worst scenario is that it is far away, it can convert some nitrogen and oxygen into the atmosphere into nitrous dioxide. The atmosphere will turn brown. It will be a slow death. “

Gamma-ray bursts come in two flavors, long and short. The former, which can last for several minutes or more, is thought to be the result of 20 times more stars than the mass of our sun breaking into black holes and exploding as a supernovas. The latter, which lasts only a second, is caused by two merging neutron stars (or perhaps a neutron star merging with a black hole), as confirmed by gravitational-wave observations, the neutron star merger and NASA’s Firm in 2017. The Gamma-Ray Space Telescope captured the associated gamma-ray explosion.

In each instance, the gamma-ray explosion does not come from the explosion itself. The lata comes from a jet moving in the opposite direction of the plane at the following fraction of the speed of light emanating from the explosion. “The exact method of powering a jet remains a” very fundamental question, “” said Xu.

This artist’s point of view shows the moments before and after Kilonova. Two neutron stars spiral inward, forming gravitational waves (pale arc). After the merger, the jet produces gamma rays (magenta), while the expansion of radioactive debris produces ultraviolet (violet), optical (blue-white) and infrared (red) light.

Niall Tanveer, an astronomer at the University of Leicester in England, said: “It means we can see them from afar.” An average observable gamma-ray burst is thought to occur in the daily visible universe.

Until recently, the only way to study gamma-ray explosions was to observe them from space, as the Earth’s ozone layer prevents gamma rays from reaching the surface. But as gamma rays enter our atmosphere, they merge into other particles. These particles push faster than the speed of light into the air, leading them to emit a blue glow called Cherenkov radiation. Scientists can then scan for these blue bursts of light.