How gamma ray bursts can wipe us out
Gamma-ray bursts are absolute beasts, the most energetic phenomena observed in the universe.
They are likely to be formed by the accretion disc of a black hole or in other extreme events, such as the collapse of a very massive star.
The main factors for estimating whether they can be a danger to life on earth are their distance and the direction in which they are oriented. We have no way to predict when these events happen or in which direction the bolts are pointed, at least as far as I know; the only variable that remains is the distance, which I think is in our favor, if I have to guess.
Dense objects tend in fact to “fall” lower into the gravity well of more massive celestial bodies, which is also the reason terrestrial planets are closer to the sun, despite being much lighter than gaseous planets.
For similar reasons, more massive objects such as neutron stars and black holes — the sources of gamma-ray bursts — are located far from the periphery of galaxies, where our solar system is located. Therefore, I would say that the chances of it happening near us are quite low.
If such an event were to happen relatively close to earth, it would destroy the ozone layer that protects us, set fire to the atmosphere, make the oceans evaporate and life on earth unsustainable for the vast majority of living beings. In this case, not being able to predict these events is probably a blessing, since we couldn’t do anything about it anyway.
And gamma-ray bursts also travel at the speed of light, so we wouldn’t even see them coming.