Researchers have built an algorithm that can scan old astronomical images for unnoticed space rocks, helping to detect objects that could one day imperil Earth.
NASA recently announced that it had detected more than 5,000 exoplanets, so we asked astronomers, actors and an astronaut to share their favorite worlds orbiting distant stars.
An asteroid hunter detected the small object two hours before it crashed into the sea near Greenland, a sign of the growing sophistication of NASA’s planetary defense system.