About one second after the Big Bang, neutrinos stopped interacting with the rest of matter. They have filled the Universe ever since: there are an estimated 340 or so per cubic centimetre, including all around you right now. These ghost particles are so elusive that no detector has yet managed to catch this cosmic background directly.
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.