Our galaxy didn't form in one piece: it swallowed many smaller galaxies. The Gaia satellite identified stars from a major merger about 10 billion years ago, named Gaia-Enceladus. And the feast goes on: the Sagittarius dwarf galaxy is being torn apart by the Milky Way's gravity right now.
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.