Most of Earth's Heavy Elements Come From One Place

All of the matter in the universe heavier than hydrogen or helium was made after the Big Bang in stars. However, standard nuclear fusion can only produce elements as heavy as iron; once a star tries to start fusing iron, the fusion reaction requires more energy than it puts out, causing said star to go supernova. It's during the supernova that all the heavier elements are made, however, supernovae are not the only way heavy elements come into being. The collision of two neutron stars also produces heavy elements, and according to new research, such a collision was responsible for seeding our solar with a vast quantity (something like 1 quintillion tons) of heavy elements such as gold and uranium.

According to the scientists, the specific collision happened about 1,000 light years away from the stellar nebula that our solar system formed out of, and occurred about 80 million years before the sun was born. This conclusion was reached through analysis of ancient meteorites, and the elements leftover from radioactive decay within those meteorites. Those elements were consistent with what a neutron star collision would have produced, not a supernova.

While we should be grateful for that collision all those eons ago (specifically, the iodine produced is essential for life), if such an event happened at that proximity today, it would create a gamma ray burst that would essentially torch our atmosphere, causing a mass extinction. Well, if we were unlucky enough to be on the business end of one of the poles of the black hole that would be formed in the process. Fortunately, these things don't happen very often, so no need to worry.