Torn apart by Jupiter's gravity, comet Shoemaker-Levy 9 had broken into about twenty fragments. In July 1994, they slammed into the planet one after another over six days. Some of the dark scars left in the atmosphere were wider than Earth. It was the first collision between two Solar System bodies ever watched as it happened.
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.