Imagine a beam of energy traveling throughout the universe and frying everything in its path. This may sound a little bit like science fiction, but these beams of energy are real and pose a real (if remote) threat.
These beams are called gamma-ray bursts (GRBs) and are so powerful they can cook anything standing in its way. These bursts originate from black holes and shoot off perpendicular to the plane of the material disk surrounding the black hole. As a star collapses or two neutron stars collide, a lot of energy is released, arriving in the form of a GRB.
The Earth’s ozone normally protects life from gamma rays that come from our own Sun, but a fully-powered GRB from within our galaxy would destroy the ozone layer and cook the side of the Earth that got touched by the burst. Gamma rays are so energetic they can rip apart DNA and electrons off atoms. They also move at the speed of light so if one was headed our way we would not know until it was too late.
Now GRB’s are not very common, and one would not only have to originate in our own Milky Way galaxy, but to also be headed in our direction for it to be of serious danger. The closest black hole candidate, A0620-00, is roughly 2,800 light-years away. The life on Earth is more likely to be destroyed by an asteroid impact or climate change than a GRB so do not fret too much.
Check out the video below by Kurzgesagt to learn more.
