[drewboy12]

fyp

Originally Posted by troutman

The radiation on Mercury must be extreme.

http://en.wikipedia.org/wiki/Mercury_%28planet%29

It orbits the Sun once in about 88 Earth days, completing three rotations about its axis for every two orbits.

Due to its near lack of an atmosphere to retain heat, Mercury's surface experiences the steepest temperature gradient of all the planets, ranging from a very cold 100 K at night to a very hot 700 K during the day.

The surface temperature of Mercury ranges from 100 K to 700 K[45] due to the absence of an atmosphere and a steep temperature gradient between the equator and the poles. The subsolar point reaches about 700 K during perihelion then drops to 550 K at aphelion.[46] On the dark side of the planet, temperatures average 110 K.[47] The intensity of sunlight on Mercury’s surface ranges between 4.59 and 10.61 times the solar constant (1,370 W·m−2).[48]

Although the daylight temperature at the surface of Mercury is generally extremely high, observations strongly suggested that ice (frozen water) existed on Mercury. The floors of deep craters at the poles are never exposed to direct sunlight, and temperatures there remain below 102 K; far lower than the global average.[49] Water ice strongly reflects radar, and observations by the 70 m Goldstone telescope and the VLA in the early 1990s revealed that there are patches of very high radar reflection near the poles.[50] While ice is not the only possible cause of these reflective regions, astronomers believe it is the most likely.[51]

The icy regions are believed to contain about 10^14–10^15 kg of ice,[52] and may be covered by a layer of regolith that inhibits sublimation.[53] By comparison, the Antarctic ice sheet on Earth has a mass of about 4×10^18 kg, and Mars' south polar cap contains about 10^16 kg of water.[52] The origin of the ice on Mercury is not yet known, but the two most likely sources are from outgassing of water from the planet’s interior or deposition by impacts of comets.[52]