In weightlessness, nothing pulls tears downward. Surface tension keeps them stuck to the eye, where they pool into a growing ball of water that eventually stings. Astronauts have to dab them away with a tissue. Canadian astronaut Chris Hadfield demonstrated it on camera from the International Space Station in 2013.
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.