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164 points pseudolus | 1 comments | | HN request time: 0s | source
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blindriver ◴[] No.42474421[source]
I don't know if I'm shocked or not shocked that the temperature is 2500F 4 million miles away from the Sun. Part of me expected it to be much much hotter than that, but I guess it is 4 million miles. Considering we are 90 million miles away, and the temperature still gets up to 120F on the Earth, maybe that makes sense?
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thisisbrians ◴[] No.42474803[source]
you're probably getting downvoted because there isn't really a temperature 4 million miles away from the Sun (it's mostly just empty space being bombarded by radiation)

2,500º F is merely the temperature the probe is expected to reach at that distance. if it were to stay at that distance indefinitely, it would grow much, much hotter as it absorbed more energy from the sun.

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tomnicholas1 ◴[] No.42475060[source]
No not necessarily - it will keep growing hotter until the black body radiation emitted by the probe matches the power of the radiation hitting the probe. Then it will stay at constant temperature.

It's a standard undergraduate problem to work out what this equilibrium temperature is for a flat plate at a distance from the sun equal to the Earth's orbital radius.

Interestingly the result is only a few 10's of degrees less than the average temperature of the real Earth - the difference is due to the Greenhouse Effect.

For the probe one could easily do the maths but I could believe that at 4 million miles that equilibrium temperature is 2,500F.

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1. thisisbrians ◴[] No.42484093[source]
i definitely can't do the math myself, but excellent retort. thank you for the nuance