3-1 The Inner Planets

Mercury, Venus, Earth and Mars are the inner planets.  These planets are the closest to the sun.  Mercury, Venus, and Mars are like Earth in that they have a solid, earthy surface.

Mercury, the planet closest to the sun is very tiny.  It has no water or air.  Days on this planet are much hotter and its nights are much colder than any place on Earth.  In 1974 and 1975 the United States space probe Mariner 10 took photos of this planet.  The pictures sent back to earth show its surface marked with wrinkles and craters.

Venus is located between Mercury and Earth.  It has no light of its own just like other planets, however it does reflect the sun's light.  Other than the moon, it is the brightest body found in the night sky.  It is the hottest planet.  Pools of liquid metal are visible on its surface.  The clouds found on Venus are made of acid.  Lightning storms are common on Venus, and it might have erupting volcanoes as well.  It is believed that Venus probably had oceans on it in the past.

Our home, the planet Earth, is the third planet from the sun.  As far as we know it is the only planet to support life.  It has one moon.

The fourth planet, Mars is nicknamed "the Red Planet."  It can be seen at night from Earth without a telescope.  The United States sent two Viking space probes to the planet.  Evidence indicates that Mars once had rivers.  Mars has two moons - Phobos and Deimos.

After the planet Mars is an asteroid belt.  Asteroids are chunks of metal and rock that orbit the sun.  They are smaller than any of the planets.   Some asteroids are as small as a basketball.  Astronomers think that asteroids might be the remains of a planet that was smashed into tiny pieces in a space collision.

Directions: Answer the questions below about the inner planets.