Launched in 1977, Voyager 1 is the most distant human-made object. In late 2026, it reaches the one light-day mark, about 26 billion kilometers away: a radio signal traveling at the speed of light then needs 24 hours to reach it. Nearly fifty years after launch, the probe is still talking to Earth.
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.