A galaxy like the Milky Way should produce one or two supernovae per century. Yet the last one seen here dates from 1604, described by Johannes Kepler. Others have probably gone off since, hidden behind galactic dust. The next one will likely be caught first through its neutrinos, and a worldwide network of detectors is already standing by to sound the alarm.
A large share of Earth's water molecules formed in the interstellar cloud that existed before the Sun was even born, more than 4.6 billion years ago. You are literally drinking a cosmic fossil.
By day, the Martian sky looks butterscotch because of fine dust hanging in the air. But at dusk, those same grains scatter blue light forward, creating a bluish glow around the Sun. Rovers have photographed these blue sunsets: the exact reverse of what we see on Earth.