The smallest planet in the solar system is Mercury, the closest planet to the sun. Up until now, there has been very little of footage taken of Mercury’s surface. Two NASA orbiters have been sent to Mercury; Mariner 10 in 1974 and Messenger in 2008. Mariner 10 was able to capture only 45% of the planet’s surface, and only recently, have we seen more of Mercury from the Messenger expedition in January 2008. Two more fly-by’s are scheduled to map the parts of Mercury that we have not yet seen; one for October 2008 and one for September 2009.

Mercury is grey with spidery lighter grey lines. Mercury is one of four terrestrial planets in our solar system. The other three are Earth, Mars and Venus. Its density is very close to the density of our planet at 5.43 grams per cubic centimeter comprising an inner core or molten iron, a 600 kilometer thick mantle and a crust that is 100 to 200 kilometers thick. The whole planet measures almost 4900 kilometers across the equator.

Mercury is named for the Roman Messenger God whom they based on Hermes, the Greek equivalent. The symbol for Mercury is said to be a stylized version of Hermes’ Caduceus; a short staff with two serpents entwined around it. When I look at it, I see the symbol for woman; the circle with the plus sign on the bottom, with a smile at the top of the circle. I am not sure I see the similarities between the two. Incidentally, the symbol for Mercury the planet is also the symbol for Mercury the element.

Did you think that Pluto was the smallest planet? Sorry, Pluto is not a planet anymore.

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