This is what it would take to kill all life on Earth

A giant asteroid crashing into our planet would instantly kill off millions of animals. But the aftermath of such an impact would be even more disastrous: Tsunamis, earthquakes, and vast clouds of dust blocking out the sun would lead to crop failure and mass extinction. Sixty-five million years ago, just such an event killed off 75% of species on Earth. But to really wipe life off the planet, it would take an astrophysical event so powerful that Earth’s oceans would literally boil away, according to a new study. The heat and cosmic radiation would make Earth inhospitable even to tardigrades, among the hardiest organisms ever discovered.