Unit 1

The BasicsOf Geography

Chapter 2, Section 1

The EarthInside 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

Th

e M

ilky W

ay 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*

Mercury 36 M

Venus 67.2 M

Earth 93 M 1 24 Hours 365 Days

Mars 141.6 M

Jupiter 483.6 M

Saturn 886.7 M

Uranus 1784 M

Neptune 2794.4 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 2006

5 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 EarthInside the EarthCore – 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?