Earth’s Atmosphere

Earth is surrounded by a blanket of nitrogen, oxygen, and other gases that stretch from the Earth’s surface to the boundary of outer space. These gases form Earth’s atmosphere and are held in place by Earth’s gravitational pull. Though it is relatively thin, Earth’s atmosphere plays an important role in regulating all other Earth systems. The atmosphere is where weather occurs. The atmosphere also regulates the temperature of the planet. Without an atmosphere, Earth would be too cold for life to exist. If the atmosphere were much thicker, like the atmosphere on Venus, it would be too hot. The atmosphere protects the plants and animals on Earth from too much ultraviolet radiation from the Sun. In this topic, you will learn how the atmosphere formed, its composition, and how the characteristics of the atmosphere change as elevation increases.

Essential Questions

• How did Earth’s atmosphere form?
• What gases make up Earth’s atmosphere?
• How does Earth’s atmosphere change as altitude increases?