23.2 The Terrestrial Planets
Mercury: The Innermost Planet
2nd smallest planet
Absorbs most of the sunlight that hits it & reflects only 6 %
of sunlight back into space
Cratered highlands
Smooth terrains that resemble maria
Dense planet (large iron core)
Long scarps (deep slopes) that cut across the plains & craters
(from crustal changes as the planet cooled & shrank)
Mercury has the greatest temperature extremes of any planet
Venus: The Veiled Planet
Named for the goddess of love & beauty
Orbits the sun in perfect circle every 255 Earth days
Similar to Earth in size, density, mass, & location
Covered in thick dark clouds (visible light can’t penetrate)
Basaltic volcanism & tectonic activity
80% covered by volcanic flow
8% of surface consists of highlands
Surface temp. reaches 475 degrees Celsius
Atmosphere is 97% carbon dioxide
Mars: The Red Planet
Appears as a reddish ball when looked at with a
telescope
Dark regions that change intensity during the Martian
year
White polar caps are very prominent with telescope
Martian Atmosphere has 1% the density of Earth’s
Made up of mostly CO2 & Water vapor
Mariner 9 first spacecraft to orbit another planet (1971)
Volcanoes & Canyons
Continued…
Some areas of Mars exhibit drainage patterns similar to
those created by streams on Earth
Groundwater recently migrated to the surface
Created gullies
Many believe that they were created by the collapse of
surface material caused by the slow melting of
subsurface ice
Many believe that Mars didn’t once have a water cycle
like we do on Earth
REVIEW REVIEW REVIEW
MARS
The Red
Planet
REVIEW REVIEW REVIEW
Which inner planet is the smallest?
How does Venus compare with Earth?
What surface features does Mars have that are
also common on Earth?