In 2010, the Fermi space telescope revealed two lobes of gamma rays, each stretching about 25,000 light-years above and below the plane of the Milky Way. Invisible to the eye, they cover more than half the sky. Their origin is still debated: a burst of star formation, or an old outburst from the central black hole a few million years ago.
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.