Flashcards Earth's Atmosphere & Greenhouse Effect

What is Earth's atmosphere mostly made of?

78% nitrogen, 21% oxygen, and small amounts of argon, water vapor and carbon dioxide

Where is most of the atmosphere located?

Most of its mass is concentrated close to Earth's surface; roughly 75-80% is within about 10-15 km

What does the ozone layer do?

It absorbs much of the Sun's harmful ultraviolet radiation

What is the greenhouse effect?

Atmospheric gases absorb and re-emit infrared radiation, keeping a planet warmer than it would otherwise be

Why is Venus hotter than Mercury?

Venus has a very thick carbon-dioxide atmosphere that creates an extreme greenhouse effect

Why is Mars's greenhouse effect relatively weak?

Mars has a very thin atmosphere, so it traps much less heat