On 30 June 1908, an object a few tens of metres wide exploded in the air over Siberia before it could reach the ground. The shock wave flattened some 80 million trees across more than 2,000 km². No crater was ever found, which long fuelled wild theories. It remains the largest impact in recorded history.
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.