It takes Mercury 88 days to orbit the sun, in contrast to Earth, which takes 365 1/4 days. Early observers noticed how quickly it took to orbit, and so named the planet after the fleet-footed messenger of the gods.
Mercury orbits at a speed of about 30 miles a second, traveling a total of 36 million miles as it races around the sun. Mercury's orbit is also highly eccentric; at perihelion (or its closest approach to the sun), Mercury is at 29 million miles, but a aphelion (or farthest distance from the sun) it is at about 40 million miles. As it orbits the sun, Mercury only rotates about three times in 2 of its years, making for a very long day.