Asteroids headed for a collision with the Earth, if found early enough, can be acted upon to prevent the potentially devastating consequences of an impact. One technique to divert an asteroid, called kinetic impact, uses a spacecraft to crash into the body at high speeds.This approach delivers the momentum of the spacecraft, while also providing…

Ask toxicologists how best to avoid mercury poisoning and they’ll almost certainly advise against eating too much of the wrong types of fish. (Never mind that there’s considerable confusion about what the wrong types are.) But a new study out of China shows that for millions of people at risk of eating toxic amounts of…