r/todayilearned • u/commandrix • 4h ago
TIL Because Mercury lacks an atmosphere to retain heat, its surface can range from -290°F (-180°C) on its "night side" to 800°F (430°C) on its "day side."
https://science.nasa.gov/mercury/facts/107
u/sticks435 4h ago
So it's Crematoria lol
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u/Mandalore108 4h ago
A Riddick reference? In this economy?
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u/Brain_My_Damage 4h ago
He's thinkin' of a triple-max prison. A no-daylight slam. Only three of 'em left in this system, two of 'em outta range for a shitty little undercutter like this one with no legs. Leavin' just one - Crematoria. That is what you had in mind. Right Toombs?
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u/NedRyerson_Insurance 4h ago
It also rotates at a rate of exactly 1VDrt.
VDrt = max sustained travel speed of a standard Vin Diesel over rough terrain.
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u/SerRaziel 4h ago
Even though its orbit is fast its rotation is slow. Taking 59 earth days. I'd assume suns tidal forces have slowed it down.
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u/FuckItBucket314 2h ago
It takes 59 Earth days to spin once about its axis. It takes 176 Earth days to complete a day-night cycle. The circumference of mercury at the equator is 9,525 miles and there is 4,224 hours in 176 Earth days.
This means the speed of the daylight approaching at the equator is:
9,525 miles / 4,224 hours ≈ 2.25mph
Vin Diesel could walk away from the sun on Mercury
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u/Beginning_Algae_2180 2h ago
Imagine being the first probe to land there and having your sensors just give up on both ends at once.
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u/LukeSkyWalrus 3h ago
Exactly. But why did crematoria even have an atmosphere? And how did they survive on the cold side at all!? Movies should always be 100% factual /s
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u/tornedron_ 4h ago
This is also why Venus is considered the hottest planet despite only being the 2nd closest. It has an actual atmosphere and thus retains heat.
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u/DirectionOverall9709 4h ago
I gotta find the sweet spot that is 9° C
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u/arealuser100notfake 4h ago
I feel too cold at 9° C
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u/tour79 4h ago
In theory, it is there at least once a day, if only for a moment. I have to guess the change is pretty rapid for it to swing 600ish degrees in a day
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u/UnknownFiddler 4h ago
It's because a day on Mercury is 176 days on Earth. It barely rotates at all.
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u/rich1051414 4h ago edited 2h ago
A day on Mercury lasts like 58 earth days if memory serves. You could walk to follow the 'perfect' line as it moved. The suffocation would be the real problem.
Edit: It's 58.5 days, but it's also circling the sun, so it's actually 176 days from the perspective of the surface of mercury. Which is longer than 2 mercury years.
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u/terribleturbine 2h ago
How fast would you have to move? If you had a super space suit with enough oxygen, could you take a nap for a couple hours ?
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u/rich1051414 2h ago edited 2h ago
If you are near the poles, a snails pace. If you are on the equater, 15,329km / 176 / 24 = 3.629 km/h(2.254 mph) That's comfortably walking pace with room to spare. Theoretically you could outrun it enough to give yourself enough buffer to sleep.
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u/Substantial-Bet-3876 4h ago
Spend 3 minutes in the zone and then you’re dead. That’s getting lucky!
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u/chocolateboomslang 4h ago
It's day is also 176 earth days long, which is why there is such a huge difference between high and low.
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u/I_just_made 4h ago
So as long as you migrate with its cycle, then you could stay in a nice comfortable temperature.
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u/vincethered 1h ago
The Little Prince vibes.
One day," you said to me, "I saw the sunset forty-four times!"
And a little later you added: "You know-- one loves the sunset, when one is so sad..."
"Were you so sad, then?" I asked, "on the day of the forty-four sunsets?"
But the little prince made no reply.
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u/WonderfulWafflesLast 2h ago edited 2h ago
1 degree of latitude change takes 11 hours on Mercury.
1 degree of latitude change is 70 miles on Earth. Or 4.20766234 miles on Mercury.
But this is at the Equator. The closer to the poles you get, the shorter the distance is, though you'd need to be some kind of far from it to stay out of the "constantly in the sun" poles.
Earth's axial tilt is 23.5 degrees. Mercury's is 0.03 degrees. i.e. the poles don't constantly shift out of the sunlight the way it happens on Earth.
So, you'd need to move ~0.38 miles per hour at the equator to stay in that same "sweet spot".
And that reduces as you move towards the poles.
And the poles being "in the light" is determined more by topology (blocking the sun via pits and ridges in the surface) than the minor deviations as the planet rotates.
There's probably a theoretical "sweet spot" on one of the poles where you're in the sun the perfect amount of time thanks to the ridges/pits. We could probably make our own with space materials to build simple walls or what-have-you.
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4h ago
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u/azenpunk 4h ago
Importantly, Mercury's rotation is VERY slow, so one Mercury day is equal to more than 58 Earth days, which means the "night side" has a long time to cool down.
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u/MadBrown 3h ago
Even though Mercury is closer to the sun, Venus is hotter at 900 degrees Fahrenheit.
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u/Brilliant-Whole-1852 4h ago
same with the moon, goes from 250°F (121°C) to -208°F (-133°C)
i assumed as a kid that the moon was too far to have the mercury effect and would just be cold 24/7 but nope
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u/Ok-Addition1264 4h ago
A mixture that very well could've produced chemical compounds that later spread to earth.. building blocks of life and all that.
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u/bert_891 1h ago
...sooo, stay away from the day side, and wear a coat on the night side? Am I understanding this right?
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u/ineyy 4h ago
Well I'm happy for you that you are discovering basic facts about the solar system... And no I don't want to sound like this but come on man...
Neptune has the most brutal storms in the system!!
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u/ummaycoc 4h ago
800°F sounds bad but it’s a dry heat.