Atmosphere
42 questions tagged Atmosphere — spanning every one of the seven Ws.
Why is the sky blue?
Sunlight is scattered by Earth's atmosphere. Blue wavelengths (~475 nm) scatter more than other colors due to Rayleigh scattering, making the sky appear blue to our eyes.
What Is the Ozone Layer?
The ozone layer is a region of the stratosphere, 15 to 35 km above Earth, where concentrated ozone (O₃) absorbs most of the Sun harmful UV-B and UV-C radiation.
What Is an Aurora?
An aurora is a natural light display in the sky caused by charged particles from the Sun colliding with gases in Earth atmosphere.
Which gas is most abundant in air?
Nitrogen is the most abundant gas in Earths atmosphere, making up about 78 percent of it.
What are noctilucent clouds?
Noctilucent clouds are the highest clouds on Earth, glowing electric blue in the twilight sky around 80 kilometres up.
What is the Kármán line?
The Kármán line is a widely used boundary between Earth's atmosphere and outer space, set at an altitude of 100 kilometres.
What is the Stratosphere?
The stratosphere is the second major layer of Earth’s atmosphere, lying above the troposphere and below the mesosphere.
What is the ozone hole?
The ozone hole is a seasonal thinning of the ozone layer above Antarctica. It is caused mainly by human-made chemicals such as chlorofluorocarbons (CFCs).
What is the dew point?
The dew point is the temperature at which air becomes saturated with water vapour and condensation begins. When air cools to its dew point, dew, fog, or clouds can form.
What is a pressure gradient?
A pressure gradient is the difference in air pressure over distance, and it helps drive wind. The larger the difference, the stronger the wind tends to be.
Where is the jet stream located?
Jet streams are found high in the atmosphere near the tropopause, typically around 8 to 16 kilometers above Earth’s surface. They are narrow bands of very fast winds that circle the planet.
Where is the ozone hole located?
The ozone hole is located over Antarctica, mainly in the stratosphere above the South Pole region. It appears each spring in the Southern Hemisphere.
Which gas makes up the largest share of Earth's atmosphere?
Nitrogen is the most abundant gas in Earth's atmosphere, making up about 78%. Oxygen is next at about 21%.
Which place has the lowest barometric pressure naturally found on Earth?
Very high mountain summits, especially in the Himalayas such as Mount Everest, have the lowest natural air pressure at Earth’s surface.
Which volcanic eruption sent the highest eruption column ever observed into the atmosphere?
The 1991 eruption of Mount Pinatubo in the Philippines is one of the highest recorded, with an ash column rising about 35 km into the atmosphere.
Which atmospheric layer contains most of the weather we experience?
Almost all everyday weather happens in the troposphere, the lowest layer of the atmosphere. It contains most clouds, storms, and water vapour.
Whose work first explained volcanic lightning?
Volcanic lightning has been studied by many scientists, but modern explanations link it to ash, ice, and charged particles in the eruption plume. Research in the 20th and 21st centuries clarified the phenomenon.
Whose experiments first showed that carbon dioxide absorbs heat?
John Tyndall showed in the 1850s that gases like carbon dioxide and water vapor absorb infrared radiation.
Whose work first explained the ozone layer?
Sydney Chapman first proposed in the 1930s how ozone forms high in the atmosphere through sunlight-driven reactions.
Whose work first measured the structure of the atmosphere with weather balloons?
Léon Teisserenc de Bort used balloon soundings in the early 1900s to discover the stratosphere.
Whose work first measured the Antarctic ozone hole?
British Antarctic Survey scientists Joe Farman, Brian Gardiner, and Jonathan Shanklin first reported the ozone hole in 1985.
What is an exosphere?
An exosphere is the outermost layer of a planet’s atmosphere, where gas is so thin that particles can escape into space.
What is an aurora on Earth and other planets?
An aurora is a glowing light display caused when charged particles interact with a planet’s upper atmosphere and magnetic field.
Which element has the highest abundance in Earth’s atmosphere?
Nitrogen is the most abundant gas in Earth’s atmosphere, making up about 78% by volume.
Why do volcanic eruptions sometimes create lightning in the ash cloud?
Colliding ash particles build up electrical charge inside the plume, and that charge can discharge as lightning. The effect is similar to static electricity in a storm, but driven by volcanic debris.
What is a temperature inversion?
A temperature inversion happens when warm air sits above cooler air near the ground. This is the opposite of the usual pattern and can trap pollution and fog.
When was the ozone hole first discovered?
It was first reported in 1985 over Antarctica.
When did scientists first measure the greenhouse effect in the atmosphere?
The greenhouse effect was studied experimentally in the 19th century. John Tyndall’s work in the 1850s and 1860s showed that gases like water vapor and carbon dioxide absorb heat.
When was the first carbon dioxide monitoring station established?
Continuous atmospheric carbon dioxide monitoring began in 1958. The famous Mauna Loa measurements started that year under Charles David Keeling.
Where does nitrogen make up most of the atmosphere?
Nitrogen makes up most of Earth’s atmosphere, about 78 percent by volume. It is found everywhere in the air around the planet.
Where is the Antarctic ozone hole most often observed?
The Antarctic ozone hole is most often observed over Antarctica, especially above the South Pole region in spring. It forms in the lower stratosphere.
Where is the stratosphere located?
The stratosphere lies above the troposphere and below the mesosphere, starting at roughly 10 to 15 kilometers above Earth’s surface. It extends upward to about 50 kilometers.
Where is the troposphere located?
The troposphere is the lowest layer of Earth’s atmosphere, starting at the surface and reaching about 8 to 18 kilometers high. Most weather happens there.
Whose measurements first showed rising carbon dioxide in the modern atmosphere?
Charles David Keeling made precise CO2 measurements beginning in 1958 at Mauna Loa, Hawaii. The resulting Keeling Curve became one of the most important graphs in climate science.
Whose discovery showed that air pressure falls with altitude?
Blaise Pascal helped demonstrate that atmospheric pressure decreases higher up. His work led to the idea that air has weight and pressure changes with elevation.
Whose observations discovered the jet stream?
Wasaburo Oishi made early upper-air balloon observations in Japan that revealed strong high-altitude winds. His work helped identify the jet stream before it became widely known.
Whose work first showed that aerosols can affect climate by blocking sunlight?
Mikhail Budyko was among the leading scientists who studied climate balance and the cooling effects of atmospheric particles. Aerosols can reflect sunlight and influence temperatures and clouds.
Whose observations first revealed the ozone hole over Antarctica?
Joe Farman, Brian Gardiner, and Jonathan Shanklin at the British Antarctic Survey first reported the dramatic springtime ozone depletion in 1985. Their discovery led to major global action on CFCs.
Whose discovery first measured the ozone layer’s role in blocking UV radiation?
Gordon Dobson developed the Dobson spectrophotometer and made early ozone measurements. His work helped show how the ozone layer protects life from ultraviolet radiation.
How does atmospheric pressure help weather and breathing work?
Atmospheric pressure is the weight of air pressing on everything around us. It helps drive winds and also keeps air moving into and out of our lungs when we breathe.
How does the jet stream steer storms across continents?
The jet stream is a fast river of air high in the atmosphere that helps guide storm systems and weather fronts.
How does the greenhouse effect keep Earth warm?
Greenhouse gases absorb and re-radiate heat, trapping some of the infrared energy Earth sends back into space.