How Hot is Mercury?
As the closest planet to the Sun, you'd think that the temperature of Mercury is hot. Blisteringly, blazingly hot. Well, you're only half right. That's because Mercury has no significant atmosphere to trap the heat it receives from the Sun. Instead of keeping the heat it receives, keeping the planet incredibly hot, only the side facing the Sun is hot. The other side, facing away from the Sun, is nearly as cold as space itself.
Keep in mind that Mercury rotates, just like the Earth. So the face of Mercury pointed towards the Sun is always changing. Mercury takes just over 58 days to complete a single day, so every part of the planet gets a chance to face the Sun - the Mercury temperature changes depending on which part is facing the Sun.
And the Sunlight is intense. Every spot on Mercury receives 6.5 times as much sunlight as an equivalent spot on the Earth.
At its hottest point, temperatures on Mercury can rise as high as 700 Kelvin (430 °C) for the regions directly facing the Sun. And its colder side can get down to 110 Kelvin (-163 °C). But the absolute coldest parts of Mercury are the shadowed parts of the planet's polar craters. These are regions that never see sunlight, and the Mercury surface temperature can get as low as 90 Kelvin (-183 °C).
The Mercury average temperature, when you even it all out, is 452 Kelvin (179 °C).
In fact, it's in these shadowed craters where planetary scientists are hoping to find evidence of water ice that might have been on surface of Mercury for millions of years, protected from the glaze of the Sun by shadows.
Filed under: Astronomy
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