What would happen if I stuck my hand into outer space?
July 15, 2009 6:20 PM   Subscribe

What would happen if I stuck my hand into outer space?

Lets say I was somehow able to stick my hand into space somewhere between the Earth and the Moon. What would happen to it? Would it freeze immediately? Would I be able to move it for a brief moment? What would it feel like if I could? Does it matter if the sun shines on it from that distance?

I've found This Site and this site that seem to say the temperature of space around Earth is a mild 45 F. Am I reading that wrong?
posted by Tavern to Science & Nature (12 answers total) 6 users marked this as a favorite
If you were to be naked in space, your body heat would quickly dissipate and you would reach the temperature of the surrounding environment. This is dynamic equilibrium. Think of it this way: if you put an ice cube in a bowl of liquid water, eventually, the ice cube warms up and becomes the ambient temperature of its environment.
posted by dfriedman at 6:25 PM on July 15, 2009

Actually the hand is insulated since there are no molecules in space to carry away conducted heat. But it will radiate heat away; how much or how fast, I'm not sure, especially if your heart is still beating and circulating new blood into the hand.
posted by crapmatic at 6:31 PM on July 15, 2009

Best answer: There's nothing to conduct heat away so your hand wouldn't change temperature like sticking it into cold air or water. In a vacuum though the boiling point of water drops so all the water and other compounds will boil off drying you out pretty fast. If the sun was shining on it it would also get pretty hot at 1 AU from the sun. Whether you'd notice that as all the water boiled off I dunno. The first hit for "human vacuum exposure" is this:
During this time, water vapor will form rapidly in the soft tissues and somewhat less rapidly in the venous blood. This evolution of water vapor will cause marked swelling of the body to perhaps twice its normal volume unless it is restrained by a pressure suit. (It has been demonstrated that a properly fitted elastic garment can entirely prevent ebullism at pressures as low as 15 mm Hg absolute [Webb, 1969, 1970].) Heart rate may rise initially, but will fall rapidly thereafter. Arterial blood pressure will also fall over a period of 30 to 60 seconds, while venous pressure rises due to distention of the venous system by gas and vapor. Venous pressure will meet or exceed arterial pressure within one minute. There will be virtually no effective circulation of blood.
If it was your whole body it would be a lot worse, but just your hand would merely be very bad.
posted by GuyZero at 6:32 PM on July 15, 2009 [1 favorite]

The website indicates that one side would be really hot and one side would be really cold, averaging out to a balmy 45 degrees. While the average is nice, being scalded on one side of your hand and frozen on the other isn't pleasant at all. Earth is able to moderate this temperature difference a little bit by rotating on its axis and having an atmosphere.

Maybe if you were rotating your hand in space, you might be able to regulate the temperature a bit, but I can't say how much.
posted by nikkorizz at 6:34 PM on July 15, 2009

You know what a "hickey" is? That's caused by maybe a 20% loss of pressure relative to the environment. Stick your hand into space and soon the whole skin of your hand would be covered by the worst hickey (read "blood blisters") you can imagine.
posted by Chocolate Pickle at 6:38 PM on July 15, 2009

Best answer: If you were to be naked in space

The question's not "you", just "your hand."

I've never got confirmation on this but when I worked at NASA I met the astronaut "Pinky" Nelson when he was touring GSFC before his first mission. That was when they maneuvered the Solar Max observatory into the payload bay, for repairs. During the repair the live video feed was showing extreme close-ups of Pinky's hands, working on the satellite, and it looked like the fingertips of his gloves had been removed and he was handling delicate hardware out there with -- not with his bare hands, but bare fingertips. If he'd come around after the mission, I would've asked him about it; other people I've talked to had no idea. Only 45°F? Maybe it's possible, then.
posted by Rash at 6:41 PM on July 15, 2009 [3 favorites]

This basically happened to Joseph Kittinger during his world-record skydive - he lost pressure in his hand due to a suit failure. See also effects of vacuum on humans and space exposure. Your hand would cool off, but slowly given that you'd only be suffering radiative losses.
posted by 0xFCAF at 6:41 PM on July 15, 2009 [1 favorite]

Best answer: This part of a book about accidents talks about what happened to Kittinger's hand. Somewhere I remember seeing photos of it when he came back to earth and it was gruesome looking.
posted by jessamyn at 6:46 PM on July 15, 2009 [1 favorite]

Could just your hand really be naked in space and not the rest of you? What would the seal be between your hand and the rest of your body?

Special iron has to be used in high vacuum equipment because regular off the shelf iron would leak air molecules (and increase the pressure inside the chamber) like it was a sponge. I can't imagine your wrist could do much better.

So, let's say you had a space suit on and just took off your glove (but had duct tape around your wrist/space suit cuff....my guess would be that your hand would the high pressure escapable contents like it was a civ, and that the high pressure in your wrist/arm/torso etc would whoosh out too. To what extent your skin would retain all that liquid I don't know, but I would like to think that your hand would balloon up and then your arm would be a firehose of body fluids.

If i'm not mistaken outer space is in molecular flow...meaning, whatever random molecules are floating out there are just like....well, random molecules, bouncing around. The pressure of your body is at laminar flow, which means the pressure acts more like water. When molecular flow meets laminar flow, big turbulence.

I would take all of the above I just typed with a huge grain of salt.
posted by ian1977 at 6:57 PM on July 15, 2009

I have met the astronaut Jeff Hoffman a couple of times and he told a story about training in a vacuum (with simulated cold as well) at the Houston Space Center with a French astronaut who had a problem with his gloves, caught frostbite and had to have the tip of one finger amputated. So 45F doesn't seem right to me.
posted by jontyjago at 8:38 PM on July 15, 2009 [1 favorite]

Rash - you're probably thinking of the glove tips, which are a different color and material for grip and sorta make the gloves look like they're fingerless. (Obviously, it's hard to use your fingers to wiggle around a glove that's also pressurived like it's a balloon, which has been a problem since the Mercury Navy Mark IVs got specially curved, hardened fingers in the gloves - and a straight middle finger for switch-flipping. The shuttle suit's rubberized tips are derived from the Apollo A7L lunar EVA suits, which were the first ones that dealt with doing actual tasks in vaccuum, not just tests.) If you just cut the tips off the glove, it would be really hard to maintain the pressure seal within the rest of the suit, even if you duct-taped a seal like in ian1977's example there. But yeah, imagine your hand covered in a giant hickey with a nasty sunburn. It might not kill you, but it'd really suck (and you could need an amputation).
posted by The Bridge on the River Kai Ryssdal at 7:18 AM on July 16, 2009

Several people have said that radiative cooling is the only possible mechanism of heat loss, but radiation heat transfer could very well be minor compared to evaporative cooling. Every milliliter of water that evaporates from your skin will carry away several kilojoules.
posted by Mapes at 8:24 PM on July 16, 2009

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