The EarthA Very Basic Intro

Dr. Mark A. McGinleyHonors College and Department of Biological

SciencesTexas Tech University

The Earthviewed from the Apollo spacecraft

Universe

Solar System

• There are around 100,000,000,000 (one hundred billion) galaxies in the universe

• One, the galaxy surrounding the star known as the sun, is known as the solar system

http://solarsystem.nasa.gov/planets/profile.cfm?Object=SolarSys

Solar System

NASA

Fun Facts- Earth’s Orbit• Orbit around the sun-

149,598,262 km• Orbit circumference-

939,887,974 km• Average orbit velocity-

107,218 km/h

Fun Facts- Earth

• Mean radius- 6,371.00 km• Equatorial circumference- 40,030.2 km• Volume- 1,083,206,916,846 km3

• Mass- 5.9722 x 1024 kg• Surface Area- 510,064,472 km2

Third “Rock” From the Sun?

Earth is not just a rock!!

• Surrounded by gas– Atmosphere

• 71% of surface covered by water• Center of the earth is not solid

The Atmosphere

The Oceans

The Earth Is Not All Solid Rock

Are You Smarter than a 5th Grader?• Why is there “day” and “night”?• Why does the sun rise in the east and set in

the west?• Why is the day length not the same

everywhere on the planet?

The Earth Rotates on Its Axis?

Are You Smarter Than a 5th Grader?

• Why are there seasons?• Why is it hotter in the summer than in the

winter?

Rotation of the Earth Around the Sun

Key Question

• So far, the only place in the universe where we know life is found if the Earth

• What characteristics of Earth allow life to exist?