Catastrophic Crash
The impact that created Mercury's Texas-sized Caloris Basin equaled roughly 1,000,000,000,000 1-megaton hydrogen bombs. The shockwave from the collision was so powerful it created a hilly region the size of Germany and France on the opposite side of the planet.

Double Sunrise
Because of Mercury's elliptical - egg-shaped - orbit and sluggish rotation, the morning Sun appears to rise briefly, set and rise again from some parts of the planet's surface. The same thing happens in reverse at sunset. The Sun looks nearly three times as large as what you see on Earth.

Made in the Shade
Even though it will be working in temperatures up to 450 degrees Celsius (about 840 degrees Fahrenheit), sensitive parts of the MESSENGER spacecraft will remain at a pleasant room temperature thanks to a heat-resistant ceramic cloth sunshade.

Running Hot and Cold
Mercury is not only one of the hottest places in our solar system - it's also among the coldest. As darkness falls on Mercury, temperatures can drop more than 600°C (1,080°F).

Speed Racer
True to its namesake (the speedy messenger of ancient Roman gods), Mercury is the fastest planet in our solar system. It zips around our Sun at an average of 172,000 kph (107,000 mph) - about 65,000 kph (40,000 mph) faster than Earth. A year on Mercury is equal to 88 Earth days.

The Long and the Short of It
Mercury completes three rotations for every two orbits around the Sun. That means if you wanted to stay up from sunrise to sunrise on Mercury, you'd be up for 176 Earth days.