AST 2003 Lecture Notes - Lecture 14: Terrestrial Planet, Prentice Hall
Document Summary
Characteristics: closest to the sun (0. 4 au) 1974- mariner vessel travels to mercury and takes 10 photos of its craters: the planet looks like our moon, craters look to be about 800 million yeears old, bombarded with asteroid to have so many craters. Atmosphere: mostly made of hydrogen and helium, the magnetic field is 0. 1 of earths. Temperature: day= 700 k (660 f, night= 200k (279 f) Water: frozen water is found in the north and south pole of the planet inside craters in shadows. Revolution: 1 year= 88 earth days (orbit around the sun, 1 day = 176 earth days (2x the year, 1 revolution of mercury is 2-3 spin-orbits, 2 revolutions of mercury is a total orbit around the sun. 1992: a radio signal was sent out to the planet and they found that there were traces of water and ice on the. North and south poles of mercury: synchrous rotation (moon-earth) has a 1 to 1 ratio.
