The Sun's visible surface sits around 5,500 °C. Yet its corona, the thin atmosphere around it, tops a million degrees. It's as if it got hotter the farther you stepped from the fire. Magnetic fields are the prime suspects, and probes are now diving into the corona to crack the puzzle.
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.