In 1908, something exploded in the sky over Siberia with hundreds of times the energy of the Hiroshima bomb, flattening more than 2,000 square kilometres of forest. When scientists finally reached the site years later, they found no crater at all

On the morning of 30 June 1908, an object from space exploded above the basin of the Podkamennaya Tunguska River in central Siberia. It flattened roughly 2,150 square kilometres of forest, an area larger than Greater London, and tens of millions of trees were knocked down in a pattern that radiated outward from a single […]

The human genome contains traces of ancient viruses that infected our ancestors millions of years ago — and some of those viral leftovers were later repurposed into genes that help make human pregnancy possible

Both halves of this claim are well supported, and neither rests on a single study. About 8 percent of the human genome, by the standard estimate, consists of sequences left behind by ancient retroviruses. And among those sequences are a small number of genes that the body now uses to build the placenta. The viral […]