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The Inner Planets

Chapter 20 Section 3

The Inner Planets are the 4 planets closest to the Sun Mercury, Venus, Earth, and Mars

The Inner Planets are also known as terrestrial planets Terrestrial planets have rocky surfaces

The Inner Planets

Mercury is the closest planet to the Sun

Mercury is slightly larger than the Moon

Mercury

Mercury is a planet of extremes

Temperatures on Mercury can get as cold as -170oC (-274oF) and get as hot as 430o C (806o F)

Mercury has these extreme temperatures because it has a very thin atmosphere *Remember* A planet’s atmosphere is what helps

regulate the planet’s temperature (think about the Earth)

A Planet of Extremes

Venus aka the “morning star” aka the “evening star”, is the 2nd planet from the Sun Venus is not a star though, because it does not create its

own light. It shines because it reflects light from the Sun

Venus is the only planet that rotates East to West. It’s “moving backwards”!

Venus

Venus is slowww…

It takes about 7.5 months for Venus to revolve around the Sun

But it takes about 8 MONTHS for Venus to make 1 rotation.

1 Day for Venus is longer than 1 Year!!

Venus

Venus’ atmosphere is made of mostly carbon dioxide

*Remember that CO2 is a greenhouse gas

Venus is becoming hotter and hotter because it has mostly green house gas in its atmosphere Global warming is always happening on Venus

Venus’ Greenhouse

Earth is the 3rd planet from the Sun

Earth’s atmosphere is made up of 20% oxygen. This is very important for living organisms like…

humans The rest of the atmosphere is mostly made of

nitrogen and water vapor Clouds are made of water vapor

70% of the Earth is covered with water!!

Earth

Earth’s atmosphere is made up of 20% oxygen. This is very important for living organisms like…humans The rest of the atmosphere is mostly made of nitrogen

and water vapor Clouds are made of water vapor

70% of the Earth is covered with water!!

Earth

Layers of the Earth

The Earth is broken up into 3 main layers The CRUST is the outside rocky layer The MANTLE is the next layer, which is made of molten

rock The CORE is divided into a liquid OUTER CORE and a

solid INNER CORE

Earth

Mars is the 4th planet from the Sun

Mars is also known as the “Red Planet” because of its reddish surface

Mars’ atmosphere is mostly carbon dioxide

Mars – The Red Planet

Mars is the 4th planet from the Sun

Mars is also known as the “Red Planet” because of its reddish surface

Mars’ atmosphere is mostly carbon dioxide

Mars – The Red Planet

Astronomers have found remains of water on Mars The north pole of Mars contains ice!

Mars’ south pole is made of frozen carbon dioxide (aka Dry Ice)

Mars has seasons just like we do on Earth

Mars – The Red Planet