The Composition of Earth’s Atmosphere

Summary

This script explores Earth's atmosphere, highlighting its thin layer that shields us from the vacuum of space. It covers the atmosphere's structure, with most human activity confined to the first 40 kilometers. The composition is detailed, with nitrogen at 78%, oxygen at 21%, and trace gases like argon and carbon dioxide at 0.04%. The importance of understanding atmospheric composition and the stable percentages of gases over 200 million years are emphasized, setting the stage for lessons on the atmosphere's origins.

Takeaways

• 🌎 The Earth's atmosphere is a thin layer that protects us from the vacuum of space, with an approximate thickness of 100 kilometers.
• 🌐 Earth is a nearly spherical ball of rock, about 12,750 kilometers in diameter.
• ✈️ Commercial airlines typically fly between 10 and 15 kilometers, while military aircraft can reach up to 30 kilometers.
• 🏔 The highest permanent human settlement, La Rinconada in Peru, is at 5,100 meters above sea level.
• 🧗‍♂️ Humans have reached the top of Mount Everest (8,848 meters) without oxygen, but cannot stay for long due to the thin air.
• 🌀 The atmosphere's composition is primarily nitrogen (78%), oxygen (21%), and trace amounts of other gases like argon and carbon dioxide (0.04%).
• 🌿 Carbon dioxide, despite its significant role in climate change, makes up a very small fraction of the atmosphere.
• 🔢 Scientists use various units to express trace gas concentrations, including percentages, parts per million (ppm), and parts per billion (ppb).
• 🌬️ The composition of the atmosphere has remained relatively stable for the last 200 million years, with nitrogen and oxygen being the dominant gases.
• 🌟 Other trace gases in the atmosphere include noble gases like neon, helium, and krypton, as well as methane and various pollutants.

Q & A

What is the Earth's atmosphere when viewed from space?

The Earth's atmosphere, when viewed from space, appears as a thin blue line at the edge of the planet.

How thick is the Earth's atmosphere?

The Earth's atmosphere is approximately 100 kilometers across, although its outer edge gradually fades into the vacuum of space, making it difficult to determine an exact thickness.

What is the approximate diameter of the Earth?

The Earth is an approximately spherical ball of rock about 12,750 kilometers across.

Up to what altitude do commercial airlines typically fly?

Commercial airlines fly between 10 and 15 kilometers up.

What is the highest altitude at which humans can struggle to breathe without the aid of an aircraft?

Without the safety of an aircraft, humans struggle to breathe above a few kilometers into the air.

What is the highest permanent human settlement in terms of altitude?

The highest permanent human settlement is La Rinconada in Peru, which sits about 5,100 meters above sea level.

What is the composition of Earth's atmosphere in terms of the most common gases?

The composition of Earth's atmosphere is approximately 78% nitrogen, 21% oxygen, and trace amounts of other gases like argon.

What is the percentage of carbon dioxide in the Earth's atmosphere?

Carbon dioxide makes up only 0.04 percent of the Earth's atmosphere.

How is 0.04 percent expressed in parts per million (ppm)?

0.04 percent is the same as 400 parts per million (ppm).

What other gases are present in the Earth's atmosphere besides nitrogen, oxygen, and argon?

Other gases in the Earth's atmosphere include trace amounts of inert gases like neon, helium, and krypton, as well as about one to two parts per million of naturally occurring methane.

How have the percentages of common gases in the Earth's atmosphere changed over the last 200 million years?

The percentages of common gases in the Earth's atmosphere have hardly changed at all for the last 200 million years, remaining approximately four-fifths nitrogen and one-fifth oxygen.