INNER PLANETS Terrestrial Planets are the Four planets closest to the sun. These planets have rocky terrain, and have higher temperatures due to receiving more of the suns energy.

MERCURY  It appears very similar to our moon with lots of craters.  Mercury has a very small orbit and is never very far away from the sun.  The best time to view mercury is just before sunrise or just after sunset.

MARINER 10  Pictures have been taken on space missions such as the Mariner 10 space probe which measured the Environment. Atmosphere, surface and characteristics of Mercury and Venus.

 Solar system distances are measured in how far the sun is away from Earth.  That distance is measured in Astronomical Units(AU) = 150 million KM. Mercury is 0.4 AU away from the sun and experiences extreme temperatures. The daytime temperatures are over 670 K (746 f), which is hot enough to melt Tin. At night temps are around 103 K ( -274 f) which is below the freezing point of water. 1 degree Fahrenheit = K

LONG DAYS  Mercury spins very slow on its axis.  1 Mercury day = 176 Earth days.  1 Mercury year = 0.24 Earth years  This means that Mercury has 1 day every 2 years!

VENUS  Venus is 0.7 AU from the sun.  It is visible near sunrise or sunset and is often called the Morning Star or Evening Star.  Mariner 10 allowed scientist to discover that Venus has clouds of CO2 which make it very reflective.  Venus has mountains and plains like other, but differs in that it spins in the opposite direction on its axis.

 1 Venus day = 117 Earth Days  1 Venus year = 0.6 Earth Years  Venus has a 90 the atmospheric pressure that Earth does.. The increased pressure keeps traps in large amounts of Sulfuric Acid and high temperatures.  Venus temperature is 700K due to “runaway” greenhouse effect.

EARTH  How far is Earth From the sun? 1AU  The Hydrosphere is the water portion of the Earth (liquid & frozen). What happens to life under the ice?  Water acts as a Heat Piggy Bank by absorbing and releasing heat.  Ex. What parts of the country are warmer? Coastal or Inland? Why?  Earth is the only planet with large amounts of liquid surface water and is the only planet that can sustain life.

EARTH’S ATMOSPHERE  Our atmosphere protects us from radiation and sustains life.  Our atmosphere consist of 78% Nitrogen, 21% Oxygen and 1% Carbon Dioxide and other gases.  The greenhouse affect also helps with temperature control by trapping in warm air so we do not freeze at night.  The upper atmosphere blocks out harmful radiation and particles released from the sun.

 The upper atmosphere also protects us from space debris by causing it to heat up and vaporize as it enters our atmosphere.  Earth is the only planet with enough Oxygen to sustain life.  Compare our atmosphere to Venus and Mercury.

MARS Would you go to Mars? The Mars One company claims it will only cost $6,000,000,000 and will take about 7 months to get there. NASA says the total cost will be between 80 & 100 billion U.S. dollars to get humans on Mars and back.

MARS EXPLORATION  Viking 1&2 sent Probes to mars in  1997 Pathfinder mission put the Sojourner robotic rover on the surface of Mars to examine rocks.  Probes have taken images of mars that show that it has frozen Polar Caps. People want to use the frozen poles as a water source when colonizing the planet.

 Mars is 1.5 AU from the sun and orbits the sun in 1.9 Earth Years.  1 Mars day = 24.7 Earth hours.  The atmosphere is very thin and is contains lots of CO2.  Temperatures range from 144k ( -200 f ) to 300 K (80 f).  Mars has two satellites – Phobos & Deimos.  Mars is approximately 11% the mass of Earth.

VOLCANOES  Mars has the largest volcanoes.  Olympus Mons is the largest mountain in the solar system. 3 times the size of Mount Everest.  The mountains form from lava flow. The atmosphere is very thin causing low gravity.  Mars surface is dusty due to high amounts of Iron Oxide causing it’s red coloration.  The surface has lots of craters and frequent dust storms due to the unprotective thin atmosphere.

DIVIDING LINE  The Asteroid Belt divides the inner and outer planets.  Hundreds of small rocky objects (Asteroids) lie between Mars and Jupiter.