Can You Walk on Mercury?

SezMe

post-pre-born
SezMe
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My mate Ellen, (for what it's worth, that is me with her on the About Ellen page (and here is a real challenge to the photogs: that dog has black fur, black nose, black eyes, and black sh... never mind. How do you get a photo of her?)) has been commissioned to write a book for kids (~7-11) about the planets and moons in our solar system. It is NOT sci-fi, but it does attempt to use imagery to convey to kids what the environments on other planets and moons are like. It is intended to be scientifically accurate but allow for literary license to convey the wonder and magnifigance to young adults of our solar system and, by inference, our world.

The book imagines a kid astronaut who travels to several planets and moons in our solar system and tries to portray what he would actually see/experience. One of planets he visits is Mercury.

Here is the question: What would happen to the sneakers of an astronaut who walked on the surface of Mercury. OK, ok, forget all the technical/scientific conundrums and just imagine someone walking on the surface of Mercury and focus on his sneakers. Would they melt? Would they ignite? Would they harden, blister and crack? Or what?

What say you...and, possibly more importantly, do you have any urls which back up your opinion?

Thanks a lot in advance
 
They wouldn't ignite, Mercury having no appreciable atmosphere to supply the oxygen needed for combustion. The Nine Planets gives a range of 90K to 700K for the surface of Mercury, so it would be quite possible to find a locale with a "comfortable" ground temperature. At 700K, most synthetic rubbers aren't going to last long, but there's no shortage of alternate materials that will.
 
BillC said:
They wouldn't ignite, Mercury having no appreciable atmosphere to supply the oxygen needed for combustion. The Nine Planets gives a range of 90K to 700K for the surface of Mercury, so it would be quite possible to find a locale with a "comfortable" ground temperature. At 700K, most synthetic rubbers aren't going to last long, but there's no shortage of alternate materials that will.
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Bill, I'll take it that synthetic rubbers won't last long, but the question is, "How will the degradation manifest itself?" Melting? Burning (ignoring the lack of oxyent)? Hardening? Other?
 
SezMe said:
Bill, I'll take it that synthetic rubbers won't last long, but the question is, "How will the degradation manifest itself?" Melting? Burning (ignoring the lack of oxyent)? Hardening? Other?
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Hardening (and cracking) occurs when you get significant additional crosslinking between the rubber molecules: this is probably most likely for artificial rubber, which is Vulcanised (crosslinked) with sulphur, and is essentially one big molecule. It's also accelerated by high UV exposure - this is what causes degradation in rubber left in the sun on Earth.

Burning in the absence of an atmosphere is most unlikely, unless the rubber can supply its own oxidation source - not really.

Natural rubber would melt at high temperature, as it's not significantly cross-linked.
 
Oh! I thought this thread was going to be about whether it would be possible to walk on the surface of a "lake" of liquid elemental mercury.

Sorry. Normal service will now be resumed....

Rolfe.
 
Rolfe said:
Oh! I thought this thread was going to be about whether it would be possible to walk on the surface of a "lake" of liquid elemental mercury.
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Uh, yeah. :o

There's a another question with the same words, though, that might be significant to the book.

You can't walk on the moon, because the motion of walking requires a certain minimum gravitational force. That's why Armstrong and Aldrin and co bounded all over the place: Not out of exuberance, but because walking didn't work.

But I can't recall what the minimum gravity is. Mercury's gravity is more than twice that of the moon (roughly the same as Mars, in fact), so you might well be able to walk on Mercury.

Definitely not on Pluto, though, which has rather less gravity than the moon.
 
PixyMisa said:
You can't walk on the moon, because the motion of walking requires a certain minimum gravitational force. That's why Armstrong and Aldrin and co bounded all over the place: Not out of exuberance, but because walking didn't work.
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But they were exuberant as well, right? I like to think that they said, "Whee!" every so often. Probably because I would have.
 
Mercury wouldn't seem to be as much of a problem as Venus. It's a wicked planet when lead melts from the ambiant temperature.
 
SezMe said:
(and here is a real challenge to the photogs: that dog has black fur, black nose, black eyes, and black sh... never mind. How do you get a photo of her?)) [/B]
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Use highlighting lights: Shine lights that are narrow beams onto the subject from behind and above the subject. This creates light highlights, even in black hair, that make the subject stand out from the background. Use fill in light in front to eliminate the shadows.

The photo on your link might have worked if you put the sun behind them both, positioning them so it creates highlights on the dog, and used an on camera flash to fill in the shadows.
 
Simple answer, yes. Remember that Mercury doesn't rotate, one side is permanently hot, the other permanently cold. So there has to be somewhere where you can walk.
 
Rolfe said:
Oh! I thought this thread was going to be about whether it would be possible to walk on the surface of a "lake" of liquid elemental mercury.

Sorry. Normal service will now be resumed....

Rolfe.
Click to expand...

I was thinking the same thing when I saw the topic title and even most of the way through the opening post.

Talk about disappointed!
 
I too thought the question would be about the element Mercury, to which my answer was already "hell no." You'd sink up to your knees, then would have no way to keep yourself upright, and you'd fall over, with about 1/14 of your volume below the surface level.

Pragmatist said:
Simple answer, yes. Remember that Mercury doesn't rotate, one side is permanently hot, the other permanently cold. So there has to be somewhere where you can walk.
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You sure about that? I thought that Mercury was tidally locked so that its rotation and revolution rates were some rational number, just not 1.
 
CurtC is right. It was originally believed that Mercury was tidally locked to the sun, with its day equal to its year and thus keeping one face permanently turned towards the sun. Doppler radar measurements in the 1960's showed otherwise.

From Starry Night:
sidereal day=58.6 (earth) days
year = 88 days

So there's for every two orbits, it turns 3 times on its axis, a 3:2 rotation/revolution resonance, something unique in the solar system. Though it's not known if this is just a coincidence.

I guess you could make a landing on the night side shortly after nightfall and before the ground had got too cold.

I can't answer the question about rubber cracking since my chemistry has long gone dormant.. However, 700K is about the temperature of a soldering iron, so if anyone wants to run a hot soldering iron back and forth over the soles of a pair of trainers in the name of science, they can report back to us all. :)
 
BillC said:
CurtC is right. It was originally believed that Mercury was tidally locked to the sun, with its day equal to its year and thus keeping one face permanently turned towards the sun. Doppler radar measurements in the 1960's showed otherwise.

From Starry Night:
sidereal day=58.6 (earth) days
year = 88 days

So there's for every two orbits, it turns 3 times on its axis, a 3:2 rotation/revolution resonance, something unique in the solar system. Though it's not known if this is just a coincidence.

I guess you could make a landing on the night side shortly after nightfall and before the ground had got too cold.

I can't answer the question about rubber cracking since my chemistry has long gone dormant.. However, 700K is about the temperature of a soldering iron, so if anyone wants to run a hot soldering iron back and forth over the soles of a pair of trainers in the name of science, they can report back to us all. :)
Click to expand...

To CurtC: No, I'm not sure about that, looks like I was wrong, my apologies.

To BillC.: Thanks for that, apologies for the mistake. All my astronomy books are from the 1960's so I'm not exactly up to date! :)
 
Thanks for all the comments. Very helpful. And sorry to Luke, Rolfe, et. al. for not including the word "Planet" in the title. The other interpretation never ocurred to me. You musta wondered, "What kind of dumb**** question is that?" :)
 
BillC said:
CurtC is right. It was originally believed that Mercury was tidally locked to the sun, with its day equal to its year and thus keeping one face permanently turned towards the sun. Doppler radar measurements in the 1960's showed otherwise.
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Just to be completely nitpicky, a "day" is usually the amount of time it takes for the sun to make a whole circle around the sky, where the reference frame is on the surface of whatever planet you're talking about. A day on Earth is 24 hours, but the Earth does one complete spin in something like 23 hours, 56 minutes. So if Mercury were tidally locked at 1:1, "day" would have no meaning.

I checked out the Wikipedia site about the older belief about how Mercury was locked, and its 3:2 discovery in the 1960s. They said that it was thought to be locked because, at peak observation times (when it's angle with the Sun is greatest from our point of view), they would always see the same side. But with a 3:2 ratio, with one revolution, it would rotate 1.5 times. Of course, the Earth's position around the Sun would change some in that time, but it still doesn't make sense that it would look like they were seeing the same face each time. What's up with that?
 
Rolfe said:
Oh! I thought this thread was going to be about whether it would be possible to walk on the surface of a "lake" of liquid elemental mercury.
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I, too.

I bet you'd slip and fall. But my father once worked in a chemical plant, and there were huge open vats of liquid mercury. The workers used to amuse themselves by throwing a Crescent wrench into the vats and watching it bob on the surface.

This is what people did before television.
 
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