Unit 1 The Basics Of Geography

Chapter 2, Section 1 The Earth Inside and Out

Objectives Describe the solar system and the Earth’s location in it Describe the Earth’s structure and the forces that created it

The Milky Way 100 – 400 Billion Stars 50 Billion Planets The Milky Way is one of 200 Billion galaxies in the observable universe (roughly 93 billion light years)

The Solar System Our solar system consists of:  The Sun  8 Planets  Planetary Moons  Comets  Asteroids  Dwarf Planets

The Sun The Sun is a medium sized star on the edge of the Milky Way galaxy. 109 times the size of the Earth Accounts for 99.86% of the mass in the Solar System It takes 8 minutes and 19 seconds for light from the Sun to reach the Earth

Planet Definition* a body that orbits the Sun, is large enough for its own gravity to make it round, and has "cleared its neighborhood" of smaller objects * this definition only applies in our Solar System

The Eight Planets Terrestrial Planets – primarily composed of rock and metal  Mercury, Venus, Earth, and Mars Gas Giants – solid core surrounded by gases such as hydrogen and helium  Jupiter, Saturn, Uranus, and Neptune

PLANETS Distance from the Sun Mass*Number of Satellites Rotation Period* Orbital Period* Mercury36 M Venus67.2 M Earth93 M 124 Hours365 Days Mars141.6 M Jupiter483.6 M Saturn886.7 M Uranus1784 M Neptune M

Comparison of the Planets and Stars

Comets and Asteroids Comets – spheres covered with _____ and ________ Asteroid – large chunks of ______ material Comets have a visible coma while asteroids do not

Dwarf Planets Fits two of the three criterion to be a planet Term was adopted in known dwarf planets Pluto is the most well known dwarf planet Eris is the largest recognized dwarf planet

Critical Thinking 1) Why is Pluto considered a Dwarf Planet? 2) Is it possible that there is life on other planets outside our solar system?

Critical Thinking 1) Why is Pluto considered a Dwarf Planet? 2) Is it possible that there is life on other planets outside our solar system?

Structure of the Earth Inside the Earth Core – center of the Earth; made up of iron and nickel Mantle – rock layer between the core and the crust Several layers Most of the Earth’s mass Crust – thin layer of rock at the Earth’s surface

On and Above the Earth Atmosphere – layer of gases surrounding the Earth  protects Earth from radiation and space debris  medium for weather and climate Lithosphere – solid rock portion of the Earth's surface  includes the upper mantle and crust  forms the sea floor under water

On and Above the Earth Asthenosphere – layer of hot but mostly solid rock below the lithosphere Hydrosphere – all of the water elements on the Earth Oceans, seas, rivers, lake, etc All the water in the atmosphere Biosphere - atmosphere + lithosphere + hydrosphere  Part of the Earth where plants and animals live

Geographic Thinking How do the Earth’s spheres influence one another?