Mercury is the nearest planet to our "Sun". It is the second smallest of our nine Planets in this system. It's diameter is 3,100 miles and it's average distance from the "Sun" is 36,000,000 miles. Mercury revolves about our "Sun" in 88 days. Moving at a speed of 30 miles per second or 108,000 miles per hour. Mercury's rotation will complete a full turn in 59 "Earth" days. The surface temperature during the "Sun's" apex is believed to be 800 Deg./F. during the day and drops to a low of minus 150 Deg./F. at night. The surface of "Mercury" is similar to that of our "Moon". Although Mercury is considerably smaller than the Earth, it's mean density is about 5.44 grams per cubic cm, as compared to 5.5 grams per cubic cm for the Earth. Mercury's atmosphere is negligible, consisting chiefly of a tenuous layer of hydrogen, helium, sodium, potassium, oxygen, and possibly neon. Trace amounts of argon, carbon dioxide, krypton, and xenon are also present. Mercury has a weak but permanent magnetic field, this would suggest that Mercury, like the Earth, has a large iron core. The presence of such a core would
account for the high mean density of the planet.

 Lets Us Take a (4 Minute) Journey on NASA's "Messenger" Space Craft  around the planet Mercury ->

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