The Earth's Atmosphere

Question 1

What is the Earth’s atmosphere?

Answer 1

Earth’s atmosphere is a layer of gases surrounding the planet and retained by the Earth’s gravity.

Question 2

What layer of gases are contained in the atmosphere?

Answer 2

It contains roughly (by molar content/ volume) 78%
nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, trace amounts of other gases, and a variable amount (average around 1%) of water vapour. This mixture of gases is commonly known as air.

Question 3

How does the atmosphere protect life on Earth

Answer 3

The atmosphere protects life on Earth by

absorbing ultraviolet solar radiation and reducing temperature extremes between day and night.

Question 4

Where is the boundary between the atmosphere and outer space?

Answer 4

There is no definite boundary between the atmosphere and outer space. It slowly becomes thinner and fades into space.

Question 5

Three quarters of the atmosphere’s mass is within what distance of the planetary surface?

Answer 5

Three quarters of the atmosphere’s mass is within 11 km / 36089 ft of the planetary surface.

Question 6

What is the Kármán line?

Answer 6

The Kármán line, at 100 km/328 000 ft, is also frequently regarded as the boundary between atmosphere and outer space.

Question 7

What is the average temperature of the atmosphere at the surface of the Earth?

Answer 7

The average temperature of the atmosphere at the surface of the Earth is 15 °C/59 °F.

Question 8

What is the average atmospheric pressure at sea level?

Answer 8

The average atmospheric pressure, at sea level, is about 101.3 kilopascals (For divers 1 bar; about 14.7 psi).