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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

  •, 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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温室効果ガスは実際にどのように機能するのか? (How Do Greenhouse Gases Actually Work?)

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    steven861124 に公開 2021 年 01 月 14 日