A strange flash in a distant galaxy first looked like a familiar kind of stellar wreckage, the radioactive afterglow of colliding neutron stars known as a kilonova. Then it brightened again, shifted ...

Cosmic rays seen at Earth show a wide range of particle energies, from 107 electron-volts (eV) to more than 1020 eV, the latter being about the same as the kinetic energy of a 450 gram football ...

Astronomers have spotted the longest gamma-ray burst ever seen, a cosmic explosion that lasted seven hours — and they determined it could be the work of a black hole destroying a star. Gamma-ray ...

Scientists may have to rethink their playbook for studying gamma-ray bursts, the most powerful known cosmic explosions, after a blast detected in July set a new record by firing energetic jets for ...

Teams of astronomers from several institutions have discovered a strange cosmic firework in deep space that brightened the ...

A rare supernova appeared five times in the sky, giving scientists a new way to measure how fast the universe is expanding ...

Artist's rendition of GRB 250702B's ultra-relativistic jet (moving at nearly the speed of light) escaping from its dusty, massive host galaxy. Astronomers at the University of North Carolina at Chapel ...