chapter 28 venus copyright (c) the mcgraw-hill companies, inc. permission required for reproduction...
TRANSCRIPT
Chapter 28
Venus
Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Venus – not so twinlike after all!
Roman: Goddess of love and our twin sister
This is the second planet from the Sun
Mostly known as our twin sisterBut only in Size, Density, escape velocity & surface gravity only.
Venus – not so twinlike after all!
Roman: Goddess of love and our twin sister
Brightest of all the planets in the night sky from earth.Venus is often termed the “Morning Star” and the “Evening Star.”
Venus – not so twinlike after all!
• Venus is only slightly smaller than the Earth (about 0.95%), but
8000 miles 7950 miles
Venus is only slightly smaller than the Earth (about 0.95%),
Venus – not so twinlike after all!
• Venus is only slightly smaller than the Earth (about 0.95%), but that is where the resemblance stops!
– Thick clouds completely obscure the surface
Venus – not so twinlike after all!
– The surface is tremendously hot!
– ~896º Fahrenheit
– ~480º Celsius
– ~718 Kelvin
Rotation of Venus
• Of all the planets, Venus spins about its axis the slowest
– 243 days to complete one rotation
Rotation of Venus
• Of all the planets, Venus spins about its axis the slowest
– 243 days to complete one rotation
– Slow rotation creates almost no magnetic field!
https://www.youtube.com/watch?v=AgnbAcT4iMk
Rotation of Venus
• This retrograde rotation cannot be produced by tidal braking– Perhaps a
collision early in its history tipped its axis
Rotation of Venus
• Venus Revolution is 224.70 days (225 days)– MEANS: a year
is shorter than a day
The Venusian Atmosphere
• The atmosphere of Venus is very different from Earth’s:– 100 times more thicker– Surface pressure is 90
atmospheres!– 96.5% carbon dioxide
The Venusian Atmosphere
• The atmosphere of Venus is very different from Earth’s:– Thick clouds of sulfuric acid (H2SO4)
– Trace amounts of water vapor & N2
The Venusian Atmosphere
• The planet probably underwent a runaway greenhouse effect
The Venusian Atmosphere• The planet has a
yellowish sky.
The Venusian Atmosphere• Lightning storms have been spotted on Venus
• Scientist estimate that there is 100,000,000 volts of electricity in a lightning bolt on Venus
– THEY never touch the ground!!!!
Interesting features of the surface of Venus
•Venus has enormous upside-down vortices spinning over both poles of the planet.
•Unlike Earth-based tornadoes and hurricanes, which suck upward, these vortices recycle the atmosphere downward.
•Furthermore, the north pole of Venus has not one but two of these vortices!
Images from Venus
• The Russian Venera spacecraft have visited the surface of Venus– Surface temperatures of ~718K, hot enough to melt lead!– Discovered volcanic rocks
Images from Venus
• The spacecraft only lasted about an hour due to the extreme temperatures and pressure
• More recent spacecraft have mapped the surface of Venus from orbit
The Surface of Venus
• Venus has both highlands and lowlands
The Surface of Venus
• Surface features are named for prominent women in history and mythology
The Surface of Venus
• Venus is less mountainous than Earth, with more rolling plains
The Surface of Venus
• Volcanic peaks are present in the highlands
The Surface of Venus
• Volcanic peaks are present in the highlands
Recent radar map of Venus
• The surface of Venus seems to be relatively young
• Not sure is volcanic activity resurfaces the planet rapidly or not.
• No Volcano has been actually detected erupting but,,,
Recent radar map of Venus
• Evidence in 2010 did show in the clouds a “white” spot” which is believed to be caused by a volcano erupting.
• There are a few impact craters, due both to the thick atmosphere and perhaps volcanic activity.
Interesting features of the surface of Venus
Recent radar map of Venus
• Diameter
– 7,530 miles; 12048 Km
– 0.95 than earth
• Composition:
– Solid Fe, Ni core like earth’s
– Magnetic field does not exist due to retrograde rotation.
– Mantle may contain hotspots but not sure
Recent radar map of Venus
• Tilt of 3 degree
• Incline plane of 3.4 degrees
• Average Distance from Sun
– .723 AU (.7 AU)
– 67,000,000 miles 67,239,000
Venus