Beneath the icy crust of Europa, a moon of Jupiter slightly smaller than ours, lies a salty ocean tens of kilometres deep. It's thought to hold about twice as much water as all of Earth's oceans combined. It's one of the best places to look for life beyond Earth, and a spacecraft is already on its way.
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.