maya astronomy 1

maya astronomy 1 - Astronomy Chapter 5 Planets MERCURY - a...

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Astronomy Chapter 5 – Planets MERCURY - a Sun-scorched planet with dormant volcanoes, a heavily cratered surface, and a substantial iron core - closest planet to the Sun - thin atmosphere and weak magnetic field o unprotected from deadly solar radiation and countless impacts - Mariner 10 and Messenger – photographed Mercury - variety of volcanic craters - Caloris Basin – closest part of Mercury to the Sun at the planet’s perihelion - lacks extensive craterless regions o has plains with relatively small craters o older than most of the lunar maria - scarps – long cliffs believed to have developed as the planet cooled - Mercury has a higher percentage of iron than Earth o caused by dense interior o considered the most iron-rich planet in the Solar System - Mercury’s rotation and revolution are coupled o 3 to 2 spin-orbit coupling o 3 sidereal rotations while undergoing 2 revolutions around the Sun - Sun crated a significant tidal bulge on young, molten Mercury that locked into place when the planet solidified. - Mercury’s atmosphere is the thinnest of all terrestrial planets - Mercury’s temperature range is the most extreme in the Solar System VENUS - Venus’s carbon dioxide atmosphere has caused a runaway greenhouse effect. - Venus’s surface temperature is hotter than the hottest spot on Mercury’s surface. - Thick atmosphere keeps the night side of the planet almost as warm as the day side. - Temperature is always too high for liquid water. - Our knowledge of Venus’s surface first came from Soviet spacecraft that landed on the surface between 1970-1983. - Lightning has not been seen on Venus (just variations in the magnetic field that are thought to be caused by lightning. - Venus has some craters, but they are less common than volcanoes. - Lava flows would have covered many craters. - Most meteors would burn up in the atmosphere. - Sulfur in the atmosphere and volcanoes indicate Venus’s interior is still molten. - However, Venus has no global magnetic field, likely because it rotates so slowly (243 Earth days for one full rotation) and backwards.
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- Venus rotates CW, so the Sun rises in the west on the surface of Venus. - exhibits retrograde motion – orbit around Sun is opposite the direction of
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maya astronomy 1 - Astronomy Chapter 5 Planets MERCURY - a...

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