In 1998, two teams measuring distant exploding stars expected to find cosmic expansion slowing down under gravity. Surprise: it's speeding up. The discovery won the 2011 Nobel Prize in Physics. Its cause, dubbed 'dark energy', remains one of the biggest mysteries in science.
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.