Throughout Earth's history, one question rises, again and again: what were the factors that killed off a species or a population of animals?
Throughout Earth's history, one question rises, again and again: what were the factors that killed off a species or a population of animals?
Many of them are terrestrial in origin, but a mysterious event that killed off 36 percent of the ocean's genera 2.6 million years ago in the Pliocene, including the famous giant, bus-sized shark Megalodon, could have been from elsewhere: an exploding star, or supernova, just 150 million light-years from Earth.
In fact, it may even have been more than one, bombarding the planet with cosmic radiation that could have triggered climate change, as well as other effects that contributed to a mass extinction of the oceanic megafauna.
"I've been doing research like this for about 15 years, and always in the past it's been based on what we know generally about the universe - that these supernovae should have affected Earth at some time or another," said physicist Adrian Melott of the University of Kansas.
"This time, it's different. We have evidence of nearby events at a specific time. We know about how far away they were, so we can actually compute how that would have affected Earth and compare it to what we know about what happened at that time - it's much more specific."
Many of them are terrestrial in origin, but a mysterious event that killed off 36 percent of the ocean's genera 2.6 million years ago in the Pliocene, including the famous giant, bus-sized shark Megalodon, could have been from elsewhere: an exploding star, or supernova, just 150 million light-years from Earth.
In fact, it may even have been more than one, bombarding the planet with cosmic radiation that could have triggered climate change, as well as other effects that contributed to a mass extinction of the oceanic megafauna.
"I've been doing research like this for about 15 years, and always in the past it's been based on what we know generally about the universe - that these supernovae should have affected Earth at some time or another," said physicist Adrian Melott of the University of Kansas.
"This time, it's different. We have evidence of nearby events at a specific time. We know about how far away they were, so we can actually compute how that would have affected Earth and compare it to what we know about what happened at that time - it's much more specific."