The document provides a basic introduction to the Earth by discussing three key facts: 1) The Earth is the third planet from the Sun and is located in the solar system within the Milky Way galaxy. 2) Unlike a simple "rock," the Earth has an atmosphere, is over 70% covered in water, and has a molten interior, allowing life to exist. 3) Two factors that enable life on Earth are its rotation on an axis, which causes day/night cycles and seasons, and its orbit around the Sun, regulating temperatures.

1. The Earth
A Very Basic Intro
Dr. Mark A. McGinley
Honors College and Department of
Biological Sciences
Texas Tech University

2. The Earth
viewed from the Apollo spacecraft

3. Universe

4. 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

5. Solar System
NASA

6. 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

7. 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

8. Third “Rock” From the Sun?

9. Earth is not just a rock!!
• Surrounded by gas
– Atmosphere
• 71% of surface covered by water
• Center of the earth is not solid

10. The Atmosphere

11. The Oceans

12. The Earth Is Not All Solid Rock

13. 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?

14. The Earth Rotates on Its Axis?

15. Are You Smarter Than a 5th Grader?
• Why are there seasons?
• Why is it hotter in the summer than in the
winter?

16. Rotation of the Earth Around the Sun

17. 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?