C is for craters, that's good enough for me 👀 On Oct. 12, 2012, our MESSENGER spacecraft captured this targeted observation of a small area of Mercury's surface, where two smaller craters on the rim of a larger crater resemble a pair of eyes. MESSENGER was first spacecraft to visit Mercury in 30 years, and the first ever to orbit. The spacecraft mapped the entire planet, discovered abundant water ice in shadows at the poles, and unlocked knowledge about Mercury's geology and magnetic field. The mission spent a little over four years orbiting Mercury, sending back nearly 300,000 photographs and a wealth of information from its instruments. MESSENGER's mission came to an end on April 30, 2015. The planet Mercury is only slightly larger than Earth's Moon, and has a solid, cratered surface. It's the fastest planet in our solar system – traveling through space at nearly 29 miles (47 kilometers) per second. Mercury has the shortest year of all the planets in our solar system, just 88...