"We estimated an outflow from the comet's nucleus of about two tons per second, equivalent to approximately 70 Olympic ...

Usually, comets are dormant blocks of rock and ice. They only wake up when they get close to a star. The intense heat causes ...

In most narratives, the story of evolution is the story of organisms emerging from the ocean and eventually populating the land. But for some species that evolution also involved a return trip. Dozens ...