Venus
The bright and morning (evening)
star.
Moon & Venus Morning of April 22, 2009
http://www.bar-jobservatory.com/Moonvenus.html
General Properties
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2nd planet form Sun
Distance from Sun 0.72 AU
Radius: 6,051km or 0.95 Earths
Mass: 0.82 Earths
Density: 5.24 g/cm3
Average Temperature: 740 Kelvin (~470 C or
880 F)
• Number of Moons: 0
• Rotation: -243 days
• Orbital Period: 226.5 days or 0.62 years.
Phases of Venus
• Inferior planet
• Angular size changes
• Brightness changes
Phases of Venus
• Evidence that
Copernicus was
correct.
• First observed by
Galileo.
Alignments of Venus
http://planet-venus.info/index.php?document_id=100
Greatest Elongations
• Elongations occur when
an inner planet's, like
Venus, position in its
orbital path is at tangent
to the view from Earth.
• Greatest eastern
elongation occurs in
western sky
• Greatest western
elongation occurs in
morning sky.
http://planet-venus.info/index.php?document_id=710
Elongation of Venus & Mercury
March 29, 2004
Credit & Copyright: Jimmy Westlake (Colorado Mountain College)
Atmosphere of Venus
• Venus has a
thick cloudy
atmosphere
the prevents
direct
viewing of its
surface.
Atmosphere of Venus
• Venus has a very
thick carbon
dioxide
atmosphere with a
surface pressure
90 times Earth’s
• Layer of Sulfuric
acid.
• Slow rotation
produces very
weak Coriolis
effect and little
weather
Greenhouse Effect
• Visible light passes
through atmosphere
and warms planet’s
surface.
• Surface heats up from
incoming light.
• Surface reemits in
shorter infrared
waves.
• Atmosphere and
absorbs this infrared
light from surface,
trapping heat.
Atmosphere of Venus
Runaway Greenhouse Effect
• Venus closer to Sun
than Earth.
• Atmosphere is mostly
carbon dioxide, a
greenhouse gas.
Runaway Greenhouse Effect
• Runaway greenhouse effect would account for
why Venus has so little water
What have we learned?
• What is Venus like today?
– Venus has an extremely thick CO2
atmosphere
– Slow rotation means little weather
• How did Venus get so hot?
– Runaway greenhouse effect made Venus
too hot for liquid oceans
– All carbon dioxide remains in
atmosphere, leading to a huge
greenhouse effect
Landscapes of Venus
Radar Mapping
Landscapes of Venus
Venera Landers
Landscapes of Venus
Magellan Mission
Volcanoes
Landscapes of Venus
Magellan Mission
Volcanoes
Landscapes of Venus
Magellan Mission
Impact Craters