Planet Earth
Section 1 Pages 33-36
A Geograpic View
Page 33
Our Solar System
At least 9 planets exist ,and each is in its own orbit around the sun.
The planets vary in size , Jupiter is the largest .Earth ranks 5th in size among the planets , and distant Pluto is the smallest .All the planets except Mercury and Venus have moons .
Earth has 1 moon , and Saturn has at least 18 moons .All planets except Pluto are grouped into two-types Terrestrial planets and Gas Giant planets
Mercury,Venus,Earth,and Mars are called Terrestrial planets For thier solid rocky crust.
Jupiter,Saturn,Uranus,and Neptune are Gas Giant planets for being farther away from the sun.
Asteroids,Comets,and Meteroroids revolve around the sun.Asteroids are small,irregular shaped,planetlike objects. Comets are made of icy dust particles and frozen gages , look like bright balls with long feathery tails.Meteroids are pieces space debris chunks of rock and iron
Solar System
Earths heights and depths
the lowest dry land point at 1,349 below sea level is The Shore Of The Dead Sea in Southwest Asia.
Earths deepest known depression lines under the Pacific Ocean southwest of Guam in the Mariana Tench.(35,827 ft)
LandForms
Underwater landforms are as diverse as those found on dry land
Water , Land And Air
About 30 percent of the Earths surface is land, including continents, and islands which is lithosphere.
The air we breathe is part of Earths atmosphere, which is composed of 78 percent nitrogen, 21 percent oxygen, and small amounts of argon and other gases.
All humans, animals, and plants live on earths surface, close to the surface or atmosphere. The part of the Earth that can support life is the biosphere.