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Why is Venus so hot?

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We Asked a NASA Scientist.

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Well, let's start with what we know. The Earth.

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So the Earth's average surface temperature is about

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60 degrees Fahrenheit, 15 degrees Celsius.

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Our atmospheric composition is about 78% nitrogen,

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20-ish% oxygen, and then about less
than 1% of a whole bunch of other gases.

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But Venus's atmosphere isn't like Earth's.

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We know that on Earth, carbon dioxide acts as a greenhouse gas.

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So light from the Sun passes through the Earth's atmosphere.

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But CO2 absorbs some of the heat that would otherwise

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have escaped back into space.

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And it traps that heat against the Earth,
causing the Earth's surface to be warmer

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than it would otherwise have been in the absence of CO2.

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Now, imagine that same process happening on Venus, a place with over

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2,000 times as much CO2 in the atmosphere and a lot closer to the Sun.

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And it's no wonder that Venus's actual average surface temperature

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is a blistering 870 degrees Fahrenheit,

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about 465 degrees Celsius.

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So Venus, really, really hot.

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And why is it so hot?

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Much closer to the Sun.

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Massive greenhouse effect.