The Terrestrial PlanetsThe Terrestrial Planets

MercuryMercury

• Very hot/cold– Difference between hottest spots and coldest spots is

600°– Orbits the sun in 88 Earth days– Rotates on its axis in 58 Earth days– That makes its year 1 ½ days

• Cratered because of bombardment of space debris during the formation of the solar system

• Ice in craters that do not get sunlight

MercuryMercury

Taken from NASA’s Messenger spacecraft

VenusVenus

• Brightest planet in the sky– Known as the morning star and the evening

star

• 255 days to orbit the sun

• 243 days to rotate backwards on its axis

• Cratered and volcanic

• Atmosphere carbon dioxide and sulfur compounds

VenusVenus

Computer-generated picture of Venus from Magellan imaging radar

Taken from the Hubble Space Telescope

EarthEarth

• 365 days to orbit the sun

• Rotation is 23 hours 56.1 min

• Known as the “Blue Planet”

• The only planet capable of sustaining life

EarthEarth

Taken from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite

MarsMars

• The “Mysterious Red Planet”

• Atmosphere thin, mostly carbon dioxide

• 2 moons—Deimos and Phobos

• It would take 6 months for a spacecraft to get to Mars

• 685 days to orbit the sun

• Rotation—1 day, 18.2 hours

MarsMars

Taken by the Hubble Space Telescope

Asteroid BeltAsteroid Belt

• Asteroids are made of rocky and/or iron-nickel material

• Most are found in an orbit between Mars and Jupiter.

• Most are pitted with impact craters and dust left from collisions with other objects in the solar system.

• A group of asteroids called Near-Earth Asteroids orbit the sun and are close to Earth.

Asteroid BeltAsteroid Belt

The asteroid Gaspra taken by the Galileo spacecraft