Inner Planet (Terrestrial Planets)
planets inside the asteroid belt
similar to Earth (consist of mostly rock & have a metallic core)
Mercury – Messenger god, closest to sun
Fastest Revolution - 88 days to orbit
Rotation – 59 days
1/3 the size of Earth
Surface is heavily cratered resembles the moon
Trace of an atmosphere (very thin)
Temperature range high of 427ºC to - 173ºC
Not the hottest planet
~ 1/3 gravity of Earth
Last space probe Messenger Oct. 2008
No Moons
Venus – 2nd planet from sun
goddess of love/beauty
-sometimes called the twin of Earth
Revolution takes 225 days
Longest rotation = 243 days to spin
Its day is longer than its year!
And it spins backward – Retrograde
Atmospheric pressure is 90 times greater than Earth
Very dense – mostly CO2 (96%) and clouds that contain sulfuric acid, makes Venus slight yellow color.
thick atmosphere causes a runaway greenhouse effect planet traps heat making it the Hottest planet : 464ºC
3rd brightest object in the sky (morning or evening star)
Most of the surface was mapped using radar from the space probe Magellan
In 1970’s the Soviet Union space probe took the 1st pictures of Venus surface, Space probes only lasted a few minutes until they quit working in Venus harsh environment.
No Moons
Venus surface
Earth – 3rd rock from the sun
only planet known to support life
big blue marble: 70% covered in water,
atmosphere 78% nitrogen, 21% oxygen, .5% CO2, .05% other gases
Revolution = 365.25 days,
Rotation = 24 hours
1 natural satellite (moon)
Mars – 4th planet from sun (red planet)
god of war, red due to iron oxide in the rocks and soil
twice as far away from the sun compared to Earth
Yea Notes About me!! Work you students!
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Revolution = 687 days,
Rotation = 24hrs. 37 minutes
Atmosphere – very thin CO2
Temperature range from 20º C to -130ºC
-during season changes creates global
dust storms
- polar ice caps can be seen (seasonal
effects)
Surface features:
Mars has been geologically active in past
Largest mountain/volcano :
Olympus Mons
Very large canyon – Valles Marineris which shows strong evidence liquid water may have flowed on Mars in the past
Two moons: Phobos & Deimos
(fear) (terror)
23 minutes for radio signals to reach Mars
At present day would take a year or more to travel to Mars and back.
Unmanned Space Probes to Mars:
Mariner 9 – 1971 orbited Mars took 1st close pictures
Viking 1&2 Landed on Mars 1971-72 examined surface and soil, took pictures of rocky surface
Mars Pathfinder & Sojourner
, which had 1st robot cars
Spirit & Opportunity (robots) – landed in 2004 exploring Mars surface
Phoenix 2008 – confirmed water ice in polar ice caps and frozen water under Mars surface soil in areas.