When the Apollo astronauts returned from the moon, the dust that clung to their spacesuits made their throats sore and their eyes water. Lunar dust is made of sharp, abrasive particles, but how toxic is it for humans?
Last week, scientists announced the 1st known source for ghostly, high-energy neutrinos. The source is a blazar, a billion-solar-mass black hole 3.7 billion light-years away. The discovery establishes a new way to study the universe.