Earth Sciences 1086F/G Lecture Notes - Lecture 4: Magnesium, Igneous Rock, Feldspar
19 Dec 2017
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Document Summary
For many years, the only spacecraft to have made a close approach to mercury was mariner. They look similar, both rotation has been altered by tidal attraction, the surfaces are heavily crated, their large craters are flooded by ancient lava flows, both are small, airless and have ancient, inactive surfaces. Mercury is tidally coupled to the sun. Has a 3:2 ratio for every 2 revs of the sun, the planet rotates 3 times. Temperature at perihelion (point in its orbit when it is closest to the sun) is around. 427 c and at aphelion (point in orbit when its furthest from the sun) is around -173 c. Has a very thin atmosphere (actually called exosphere there) consisting of atoms blasted off its surface by the solar winds, which quickly escape into space (atmosphere is constantly being replenished: contains traces of na, k, ca, mg. Mercury has enormous cliffs that are thought to be fault systems.
