The closest planet to the Sun, Mercury was named after the Roman god of commerce, travel and thievery. The existence of this 8th largest planet has been known of since before the third century BC. The Greeks gave it two names, Apollo for when it appeared as a morning star and Hermes when it came as an evening star.
Mercury is a planet of extremes. It speeds around the Sun in a wildly elliptical (non-circular) orbit that takes it as close as 47 million km and as far as 70 million km from the Sun. The planet completes a trip around the Sun every 88 days, speeding through space at nearly 50 km per second, faster than any other planet. Because it is so close to the Sun, temperatures on its surface can reach a scorching 467 degrees Celsius. But because the planet has hardly any atmosphere to keep it warm, nighttime temperatures can drop to a frigid -183 degrees Celsius.
Mercury has no known moons or satellites.
This Image of "Mercury" was produced from USGS I-1149, 1979.
After Mercury, we head further away from the sun to reach Venus.
Also, check out our Full Detail Solar System Tour