Learn something new every Friday. Join 2,000+ nerds and satisfy your curiosity one question at a time with topics including science, technology, history, and more.
What happens to the temperature of the atmosphere the higher you go?
|
β What happens to the temperature of the atmosphere the higher you go?β
|
Let's dig into how and why each atmospheric layer's temperature changes as altitude increases.
π‘οΈπ Troposphere (0-10km): Temperature goes down
The troposphere is our home. Extending from Earth's surface to about 10km high, the troposphere is the wettest layer and contains roughly 75% of the atmosphere's total mass, mostly in the form of air molecules and water vapor.
As you go up in the troposphere, temperature will go down, reaching -60Β°F (-51Β°C) at the top. But hot air rises, right? Why does temperature decrease with altitude in the troposphere?
The primary source for air's heat in the troposphere is the Earth itself. As the Sun warms the rock, soil, and water, these surfaces emit heat. As the warm air rises, it gets further and further from this heat source, which cools it down.
Rising warm air also cools because the molecules spread farther apart due to a decrease in air pressure. The expansion of air requires energy, so the rising air becomes cooler and cooler.
π‘οΈπ Stratosphere (~10-50km): Temperature goes up
The stratosphere is the next stop in our atmosphere. As you continue climbing from to the top of the stratosphere, the temperature rises all the way to roughly 32Β°F (0Β°C).
The heating in the stratosphere is thanks to the infamous ozone layer. Ozone (Oβ) is a highly reactive gas made up of three oxygen atoms. It forms when sunlight's high-energy ultraviolet rays (UV-C) strike oxygen molecules (O2), splitting them into two individual oxygen atoms (O).
These single oxygen atoms are highly reactive and quickly bond with O2 to form ozone. When ozone absorbs UV-B radiation, it breaks apart again into O2 and O.
The continuous creation and destruction of ozone absorbs UV radiation and releases heat, warming the stratosphere as you get closer to the Sun.
The ozone layer is why we're all alive. By absorbing so much of the Sun's high-energy UV rays, ozone protects us from the DNA-damaging effects of UV radiation (this is what causes sunburns).
π‘οΈπ Mesosphere (~50-85km): Temperature goes down
Moving on up, we arrive at the mesosphere. The coldest temperatures in Earth's atmosphere are found in this layer. Here the temperature goes down as you climb higher, dropping to -130Β°F (-90Β°C) at the top.
β "Shooting star OCA" by Moini is part of the public domain. |
Temperatures drop as you go up in the mesosphere because the air pressure is extremely low. In fact, 99.9% of the atmosphere's mass is below the mesosphere, which means gas molecules are spread very far apart. In this layer, there is much less ozone to absorb UV radiation so there is less heating.
The main heating source of the mesosphere comes from the stratosphere below. The higher you go in the mesosphere, the further away you are from the radiating heat of the stratosphere, which is why it gets colder.
π‘οΈπ Thermosphere (~85-500km): Temperature goes up
Next stop: The thermosphere. As the name suggests, this is where things start heating up. Temperatures can reach as high as 3,600Β°F (2,000Β°C) at the top of the thermosphere.
β "Space Aurora ESA321897" by European Space Agency is licensed under CC BY-SA 3.0 IGO. |
In this layer, high-energy X-rays and extreme UV radiation from the Sun are absorbed by sparse gas molecules. These photons carry much more energy than visible light or UV-A light, so the temperature spikes to hundreds, even thousands, of degrees.
Still, you'd be wise to bring a sweater. While the temperatures reach astounding levels in the thermosphere, it would feel freezing cold.
Here's why: Temperature measures the average kinetic energy of particles. The atoms that make up matter are always vibrating, and how quickly they vibrate is measured as temperature.
But in the thermosphere, gas molecules are spread so far apart (one molecule can go about 1 km before it collides with another) that not enough would hit our skin in order for us to feel the heat.
π‘οΈπ Exosphere (~500-10,000km+): Temperature goes up
While the atmosphere doesn't abruptly end at any point (the air just gets thinner and thinner), many scientists consider the exosphere as its outermost layer. NASA says it ends at about 10,000 km, other authorities say it ends halfway to the moon (~190,000 km).
β "The Hubble Space Telescope in orbit" by β Hubble ESA is licensed by CC BY 2.0. |
Similar to the thermosphere, the exosphere is on the front lines of the Sun's high-energy rays. So the further you go up, the hotter it technically is, reaching over 3,600Β°F (2,000Β°C) depending on solar activity. But with even fewer gas molecules, it would still feel outrageously cold.
π‘οΈβ Outer space: Temperature doesn't really exist
Now we've truly exited Earth's atmosphere into outer space. In outer space, there are virtually no molecules left, so temperature (the average kinetic energy of particles) loses meaning.
Without any air, there's simply no air temperature. All we're left with is surface temperatures, gaining or losing heat based on whether you're in direct sunlight. Objects facing the Sun would be 250Β°F (120Β°C); whereas being a shadow would plummet surface temperatures to -275Β°F (-170Β°C).
|
--- Thanks for reading this week's newsletter! If you have any thoughts, questions, or favorite GIFs, my inbox is always open. Just hit reply to send me a note! :) All my best, |
Sources for this week's newsletter
|
π Wikipedia article of the week
Polar bear jail
"The Polar Bear Holding Facility, colloquially known as the Polar Bear Jail is a special building in Churchill, Manitoba, Canada where polar bears that are considered troublesome or dangerous are isolated until they can be relocated....The bears could be held from two to 30 days β if a bear had been captured repeatedly, the term may have been extended. The premise is that extended captivity would create a sense of danger for the bears so that they will be reluctant to approach the town."
π Catch up on other curious questions
P.S. π€ Do you have a question for the newsletter? Click here to submit your question (or reply to this email!)
|
π‘ Today You Should Know
Learn something new every Friday. Join 2,000+ nerds and satisfy your curiosity one question at a time with topics including science, technology, history, and more.
Why do men have nipples if they can't breastfeed? This question came from a reader submission (thanks Pedro's daughter!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Men have nipples because all embryos start developing the same way, and nipples form before sex-specific genes activate. They likely remain simply because thereβs no evolutionary pressure to remove a harmless trait. π The long answer Great thinkers...
Do sports teams that train in high altitudes have a home advantage? This question came from a reader submission (thanks Jacqui!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer There is strong statistical evidence that high-altitude teams have a home advantage, largely because visiting players experience reduced oxygen intake and quicker fatigue at elevation. π The long answer It's high time we level up our...
How was bread invented? This question came from a reader submission (thanks Rodrigo!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Bread originated over 14,000 years ago with early humans baking ground wild grains on hot stones. Over time, developments in agriculture, fermentation, and oven construction led to increasingly specialized and widespread bread production across ancient civilizations. This week's...