Key building blocks of DNA and proteins discovered by Rosetta spacecraft on 67P

They have been blamed for bringing worldwide destruction to Earth and triggering the kind of mass extinctions that wiped out the dinosaurs. But it appears we may owe our very existence to a comet that smashed into our planet billions of years ago. A spacecraft that has been orbiting a distant comet as it races through the solar system has sent back compelling evidence that suggests one of these icy objects brought the seeds of life to Earth. Comets are often thought of as harbingers of doom, causing mass extinctions and destruction on Earth. The European Space Agency's Rosetta spacecraft, which has been orbiting the duck-shaped Comet 67P/Churyumov-Gerasimenko since August 2014, has discovered two key building blocks of life on the enormous block of ice and dust.