The Solar System: Inner Planets

What is a planet? A planet is a body of matter that travels around a star in a fixed path called an orbit. Planets don’t give off their own light…they reflect the light of the Sun.

Planets are classified as inner planets and outer planets Mercury Venus Earth Mars Outer Jupiter Saturn Uranus Neptune Pluto

THE INNER PLANETS A.K.A Terrestrial Planets- Earth Like All composed of a solid rock surface If we had the proper technology, we could travel across these planets collecting samples

MERCURY

Mercury is the closest planet to the sun. Mercury is only about one-third the size of Earth It is smaller than any other planet except Pluto Year lasts 88 days (revolution) It takes 59 Earth days for one complete rotation

Lack of Atmosphere Because it is so close to the sun, Mercury has no atmosphere Therefore, it has no weather Temps. During the day can be 427 degrees Celsius (800 degrees F.) and fall during the night to -170 degrees Celsius (-274 degrees F.)

Craters on Mercury U.S. Space Craft, Mariner 10, flew past Mercury in 1975 Landscape is covered with craters from material striking the planet

VENUS

Venus is the second planet from the sun Has a similar diameter, mass, and density as Earth- Thus Venus is known as Earth’s Twin! They differ in that Venus does not have oceans or human life Also, it’s temp. reaches 484 degrees Celsius (903 degrees F.) In 1975, two Soviet Space Craft landed on Venus and were destroyed within hours due to harsh atmospheric conditions

Way Too Much Atmosphere! Thick blanket of dense clouds high up in the planet’s atmosphere These clouds contain sulfuric acid which gives them a yellowish color Beneath this cloud layer is a layer of Carbon Dioxide Gas This gas is much denser than the nitrogen and oxygen that makes up our atmosphere on Earth

DO YOU HAVE ANY IDEAS WHY VENUS GETS SO HOT?

It’s so hot because…… Carbon Dioxide traps the heat and causes the greenhouse effect. It acts like the glass in a green-house and traps all the heat inside.

More Facts Sixth largest planet It rotates opposite of all other planets- clockwise The Venusian day takes 243 Earth Days The Venusian year lasts 224 Earth Days

Temperatures can reach 484 degrees Celsius (903 degrees F.)! Highest temperature on Earth has been 58 degrees Celsius (136.4 degrees F.) RADAR picture Blue=smooth Brown =rough

EARTH

Third Planet from the sun Fifth Largest Planet Only planet known to support life Surface contains 70% water and 30% land Atmosphere is 78% nitrogen, 21% oxygen, and 1% argon Water exists in all three states of matter

It takes 24 hours to rotate around the axis- which equals one day It takes 365 days to revolve around the sun It has one satellite- the moon

MARS

Mars is the 4th planet from the sun 228 million km from sun Seventh largest planet In 1976 Viking 1 and Viking 2 probes landed on mars to give us important new information on the atmospheric conditions and rugged landscape

The Martian atmosphere is very thin, and solar winds carry it Away because Mars has a weak gravitational and magnetic field The Martian soil is coated with a reddish compound also known as rust...can you guess what this compound would be? Surface covered by rocks and soil The surface of Mars is very cold: A high temp. may reach -20 degrees Celsius (-4 degrees F.) to a low of -140 degrees Celsius (-220 degrees F.)

Olympus Mons Largest known volcano in the solar system 3 times taller than the tallest mountain on Earth Base would stretch from Washington D.C. to Boston Volcanoes are dormant or inactive

Valles Marineris Valles Marineris is Mars’ largest canyon. If placed on Earth, It would stretch from New York City to Los Angeles

Why is there no life on Mars? The Earth’s ozone layer absorbs harmful UV rays from the sun Mars has no ozone. It lacks the simplest molecules because they can’t survive the UV rays

Earth sounds pretty nice right about now, doesn’t it?