To capture infrared light, the faint heat of the very first stars and galaxies, the telescope must be ice cold. So it orbits a balance point 1.5 million kilometres from Earth, about four times the Moon's distance. A sunshield the size of a tennis court separates a side at about 85 °C from one near −233 °C. Its 6.5-metre mirror has 18 gold-coated segments.
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.