Planet of Love (and sulfuric acid rain) Venus Planet of Love (and sulfuric acid rain)

Order of Topics Properties Orbit and rotation Composition and internal structure Surface features and history Atmosphere Magnetosphere

Physical Properties of Venus Mass 4.870 x 1024 Kg Mean radius 6.1 x103 Km Mean density 5244 Kg/m3 Rotation Period 243.025 Earth Days (Retrograde) Orbital Period 224.7 Earth days Mean Distance From Sun 1.1 x 108 Km (0.723 AU) Atmosphere 96% CO2 and 3.5% N Surface Pressure 92 Bars Surface Temperature 735 Kelvin Magnetic Field Strength < 0.001 (Earth =1)

Point 1 Venus is a Evening Star Venus’s Synodic Cycle Point 1 Venus is a Evening Star Point 2 Venus is an Evening Star Between points 3 and 4 Venus is not visible Point 5 Venus is an Morning Star Point 6 Venus is a Morning Star 1. Venus appears after being invisible due to passing behind the sun, from the perspective of the earth. Venus is invisible for about fifty days between point 6 and point 1. At point 1 and until it reaches point 3, Venus will be "east of the sun" and therefore will be trailing the sun, and thus it will be the evening star. 2. Venus reaches its point of "maximum eastern elongation" -- the greatest angle of separation from the sun on this side of its orbit, as viewed from the earth (it will reach the same maximum angle again on the other side of its orbit, at point 5). This maximum angle of separation from the sun (or "elongation") is about 47o for Venus. 3. Venus begins to be "swallowed up" by the sun and hence invisible. This is somewhat analogous to the new moon, except that the moon goes from being ahead of the sun to trailing the sun at the new moon, and Venus goes from being an evening star that trails the sun to being a morning star that leads the sun during this time. Venus will be invisible for approximately eight days between point 3 and point 4. 4. Venus emerges onto the western side of the sun, and will now be the morning star (it may be somewhat confusing to learn that Venus is termed "west" of the sun when it is a morning star, since morning stars are seen in the east, but the way to reconcile this terminology is to think about the fact that when Venus is the morning star, it will be closer to the western horizon than the sun at daybreak: it will be ahead of the sun when the sun comes up in the morning over the eastern horizon -- Venus will already be a bit ahead of the sun and on its way towards the west). Venus will be the morning star from point 4 through point 6. 5. Venus reaches its point of maximum western elongation, which is analogous to the situation described in point 2 above. 6. Venus disappears behind the sun for another fifty-day period, enroute to starting the synodic cycle over again

Venus has a thin crust with active volcanoes No plate tectonics Geology of Venus Venus has a thin crust with active volcanoes No plate tectonics Mostly flat or rolling hills Two small uplift plateaus The varied terrain of Venus, including volcanoes, mountains, craters, and lava flows, suggests that the planet was once, and perhaps still is, geologically active.

The interior of Venus is probably similar to Earth's interior The interior of Venus is probably similar to Earth's interior. Venus, like Earth, is one of the terrestrial planets and is made of rock and metal. It probably has a partly molten metallic core, a rocky mantle, and a crust.

Surface Age Some large, old craters About 1000 over the surface Thick atmosphere prevents small meteors from reaching surface Some lava flows free of craters About 1/10 the cratering rate of the Moon 200 million to one billion year old surface

Close-up images of the surface show that some form of deposition and erosion occurs. Thanks to the Pioneer, Magellan and Venera radar orbiters, the surface of Venus is now mapped more completely and uniformly than the Earth. Radar mapping from earth and from orbit indicate large valleys and plateaus, probably craters, and large volcanic complexes. The plateaus on Venus are not continents as on the Earth, and overall Venus is much smoother than Earth. Venus has numerous volcanoes. Some scientists think the sulfuric acid in Venus' atmosphere may be of volcanic origin. Venus seems to have had a planetwide volcanic episode about 600 million years ago that covered much of its surface and covered its earlier craters.

Atmospheric Composition of Venus Traces of Sulfur Dioxide Water Vapor Argon In the upper clouds, the temperature is near 280 Kelvin At about 80 Km from the surface the temperature drops to about 150 K From about 80 Km up from the surface down to the surface the temperature increases to about 8oo Kelvin

Venus Globe The highly efficient greenhouse gases on Venus have scorched its surface. The temperature on Venus is about 735 K. The dense atmosphere evens out the temperature and has eliminated seasons on Venus. Slow winds near the surface rotate with the planet once every 243 days.

Two things needed for a magnetic field. There is no appreciable magnetic field on Venus, but its dense atmosphere deflects solar winds. Two things needed for a magnetic field. Liquid metal core Rapid Rotation The planet rotates very slowly, taking more than 243 Earth days to spin once on it's axis (even longer than the time it takes for Venus to orbit the Sun, about 225 Earth days).

UV Venus The pale yellow clouds of Venus are composed of concentrated sulfuric acid droplets. It takes only 4 days for the upper level clouds to travel around Venus, being pushed by fierce rapid winds.

Venus Transit A transit of Venus occurs when Venus passes directly between the sun and earth.  This alignment is rare, coming in pairs that are eight years apart but separated by over a century.  The most recent transit of Venus was a thrilling sight in 2004.  After the June 2012 transit of Venus (the last one in your lifetime), the next such alignment occurs in 2117. 

Venus and the Moon, Western Colorado Venus is the 3rd brightest object in the sky (after the sun and the moon). Venus is the brightest planet in the Solar System. Venus only appears in the evening or morning hours, but never in the middle of the night. Venus and the Moon, Western Colorado