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  • The earth and the moon are basically the same distance from the sun, yet temperatures on

  • the moon average an unlivable -18°C, and even deadlier, they range from -170°C during

  • lunar night to 100°C at lunar noon, regularly exceeding both the coldest and hottest temperatures

  • ever recorded on Earth. And while the days and nights on the moon are about 14 times

  • longer than those on Earth, our planet’s relatively fast rotation isn’t what spares

  • us from those loony temperatures. What protects us is our atmosphere. By day,

  • it serves as a shield, blocking out the most harmful and energetic of the sun’s rays

  • and about one-third of the less-intense visible light. At the same time, it traps the infrared

  • radiationaka heatradiating out from Earth’s sun-warmed surface, keeping us from

  • freezing solid at night. In order for our atmosphere to absorb any

  • kind of radiation, it needs to have some electrically charged particles for passing electromagnetic

  • waves to push around. And most of our atmosphere is made up of gas molecules that don’t have

  • an electric chargethey all have a balanced number of positive protons and negative electrons.

  • But some hold most of their negatively-charged electrons closer to one side, lending them

  • a lopsidedness that can jiggle back and forth to absorb the energy of incoming infrared

  • rays. For example, water, ozone, and nitrous oxide are all electrically lopsided, so they

  • all absorb infrared radiation. Then there are gases like carbon dioxide and

  • methane. On paper, neither molecule looks lopsided, so it doesn’t seem like they should

  • be able to absorb any radiating heat. But in reality, gas molecules aren't motionless

  • they crash into each other billions of times per second, knocking each other in different

  • directions, and also into different modes of rotation and vibration. And it turns out

  • that both carbon dioxide and methane spend most of their timeshaking itin electrically-lopsided

  • ways, allowing them to absorb infrared rays and help insulate the earth.

  • Even though many different kinds of molecules can absorb infrared radiation, the vast majority

  • of our atmosphere can’t, because it’s made of nitrogen and oxygen, which don't get

  • lopsided even when they are vibrating - theyre too symmetric. Nevertheless, the lopsided

  • 1% are such good infrared absorbers that they manage to intercept about 90% of Earth's outgoing

  • heat. Each captured ray gets pinged around the atmosphere, and most end up returning

  • to the surface at least once before escaping to space.

  • We don’t need to visit the moon during frigid lunar night to know just how important the

  • game of radiation-pinball is for Earthice records from our own coldest climate show

  • that small, natural variations in atmospheric carbon dioxide produce relatively big changes

  • in temperature. They also show that, compared to the last 800,000 years, the game today

  • is much, much harder.

  • Thanks so much to the great team over at Kurzgesagt for doing the animations in this video, it’s been a lot of fun working with them! And if

  • you liked what you saw, you can go to the link here or in the video description to check

  • out their channel, where they cover everything from neutron stars to fracking to the Islamic

  • State. Thanks again, Kurzgesagt. And thanks as well to everyone who has supported us on

  • Subbable.com, which has now merged with Patreon.comyou make MinuteEarth possible.

The earth and the moon are basically the same distance from the sun, yet temperatures on

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