# Planet/moon most inhospitable to humans? **URL:** \ **Category:** Factual Questions\ **Created:** [January 19, 2011, 7:48am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184 "2011-01-19T07:48:49Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Mr.Kobayashi](https://avatars.discourse-cdn.com/v4/letter/m/4af34b/32.png) [@Mr.Kobayashi](https://boards.straightdope.com/u/Mr.Kobayashi)\ **Post date:** [January 19, 2011, 7:48am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/1 "2011-01-19T07:48:49Z")
Another space question, this time from the recesses of my tiny little mind rather than a dodgy sci-fi film. For the purposes of the question I’m kicking it old skool, and including Pluto and Charon. Oh, and in the Solar System - I’m not interested in hypothetical Planet X’s or vague wobbles in distant stars. The gist of the question is as followed - if an average human was transported to the surface of any of the planets or their moons, which would kill them the quickest? We’ll do two experiments - one a vanilla human, no special protection. The second chap gets the same kind of suit Neil Armstrong and Buzz Aldrin wore on the moon. My money for both experiments is on Venus; due to the pressure and heat. Although I have to admit I have no idea how one would fare hurtling into the centre of a gas giant, or if the gas giants would vary any, whether Jovian gravity or the gas compositions would matter. Would you be blown into the centre until you suffocated, or instantly buffeted and torn to pieces by the currents? Are parts of Earth serious contenders - the ocean floor, perhaps? I’m expecting a few draws as gruesome deaths may be relatively instantaneous. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [January 19, 2011, 10:13am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/2 "2011-01-19T10:13:37Z")
If you were telelported to Venus the atmospheric pressure would kill you almost instantly. The pressure is about the same as 1km under water on Earth, your lungs would be crushed and death would be mercifully quick. The Marianas trench on Earth might kill you a fraction of a second quicker due to the higher pressure, it’s 2.5 km deep. Other candidates would be an active volcano on Earth, or on [Io](http://en.wikipedia.org/wiki/Io_(moon)#Volcanism). A space suit would offer no protection. Anywhere else, I think you’d asphyxiate before dying from some other cause. A space suit would offer some protection in these environments. On Mercury, the heat would kill you, but it might take a little while. Radiative heat transfer is far less efficient than conduction. If you could stay on your feet (probably unrealistic), I’d guess it might be possible to survive for a few minutes. If you fell into a gas giant the pressure would slowly increase as you fell deeper, eventually killing you. ---
**Author:** ![Hairy\_Bob](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Hairy\_Bob](https://boards.straightdope.com/u/Hairy_Bob)\ **Post date:** [January 19, 2011, 11:46am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/3 "2011-01-19T11:46:47Z")
> [@Alka\_Seltzer](#): > > The Marianas trench on Earth might kill you a fraction of a second quicker due to the higher pressure, it’s 2.5 km deep. Must correct you on that point, from wikipedia; The Mariana Trench is the deepest part of the world’s oceans, and the lowest elevation of the surface of the Earth’s crust. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about 2,550 kilometres (1,580 mi) long but has a mean width of only 69 kilometres (43 mi). It reaches a maximum-known depth of about 11.03 kilometres (6.85 mi) at the Vityaz-1 Deep[citation needed] and about 10.91 kilometres (6.78 mi) at the Challenger Deep and; At the bottom of the trench, where the plates meet, the water column above exerts a pressure of 1,086 bars (15,750 psi) ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [January 19, 2011, 11:48am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/4 "2011-01-19T11:48:34Z")
Ah, thanks, my wiki-reading skills must be off today. ---
**Author:** ![Hairy\_Bob](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Hairy\_Bob](https://boards.straightdope.com/u/Hairy_Bob)\ **Post date:** [January 19, 2011, 11:55am UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/5 "2011-01-19T11:55:44Z")
Missed the edit window. Good points otherwise, AS, fwiw I would say the bottom of the trench would crush you slightly faster than a volcano would melt you, but not so’s you’d notice. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [January 19, 2011, 1:31pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/6 "2011-01-19T13:31:48Z")
I agree. In lava, you’d survive as long as it long as it took your body to collapse, and then the actual cooking wouldn’t be quite instant. You might even have time to scream. For instantly lethality, I don’t think you can top the Marianas trench. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [January 19, 2011, 2:31pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/7 "2011-01-19T14:31:23Z")
How about dayside, Mercury, high noon? ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [January 19, 2011, 2:34pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/8 "2011-01-19T14:34:10Z")
For the gas giant planets, ‘surface’ is not a relevant concept, is it? ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [January 19, 2011, 2:39pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/9 "2011-01-19T14:39:56Z")
Surface of Jupiter might be a contender as well. It’s a long way down and possibly just liquid metallic hydrogen. So you’d have tremendous pressure, cold, and possibly even massive lightning bolts to contend with due to the metallic nature of the core. Surface of Mercury gets up to 800 degrees F on one side and down to -300 on the other. So yeah, probably not a winner as you’d manage a second or two of unendurable agony for the former, and, if you believe Larry Niven, an eternity of superconducting awareness in the latter. ---
**Author:** ![fuzzypickles](https://avatars.discourse-cdn.com/v4/letter/f/9d8465/32.png) [@fuzzypickles](https://boards.straightdope.com/u/fuzzypickles)\ **Post date:** [January 19, 2011, 3:28pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/10 "2011-01-19T15:28:02Z")
If we’re allowed to look outside the solar system, crossing the event horizon of a black hole would be the worst fate imaginable. According to Stephen Hawking, the laws of physics break down at that threshold – not only are matter & energy destroyed, but so is the concept of “time” itself: > [@Stephen Hawking](#): > > \*Suppose an intrepid astronaut on the surface of a collapsing star, collapsing inward with it, sent a signal every second to his spaceship orbiting the star. At some time on his watch, say 11:00, the star would shrink below the critical radius at which the gravitational field becomes so strong nothing can escape, and his signals would no longer reach the spaceship. […] Within a few hours, as the region continued to collapse, the difference in gravitational forces on his head and his feet would become so strong that again it would tear him apart. > > The event horizon, the boundary of the region of space-time from which it is not possible to escape, acts rather like a one-way membrane around the black hole: objects, such as unwary astronauts, can fall through the event horizon into the black hole, but nothing can ever get out. […] One could well say of the event horizon what the poet Dante said of the entrance to Hell: “All hope abandon, ye who enter here.” **Anything or anyone who falls through the Event Horizon will soon reach the Region of Infinite Density and The End of Time.** – A Brief History of Time, pp. 88-92 [partially edited]\* Therefore, not only does the black hole shred your body into tiny ribbons, your consciousness _freezes_ at that moment when Time collapses – your mind becomes forever trapped in a state of infinite anguish, pain, and desperation, where no man or god can save you. Death is not an option – because, from your perspective, Time itself no longer exists. Compared to that potential fate, I’d rather be eaten by Cujo. :eek: ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [January 19, 2011, 3:33pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/11 "2011-01-19T15:33:58Z")
> [@Finagle](#): > > Surface of Jupiter might be a contender as well. It’s a long way down and possibly just liquid metallic hydrogen. So you’d have tremendous pressure, cold, and possibly even massive lightning bolts to contend with due to the metallic nature of the core. Yes, that would be another contender, although ‘surface’ isn’t really the correct term, and the layer of metallic hydrogen would be hot, not cold. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [January 19, 2011, 3:44pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/12 "2011-01-19T15:44:48Z")
> [@fuzzypickles](#): > > If we’re allowed to look outside the solar system, crossing the event horizon of a black hole would be the worst fate imaginable. According to Stephen Hawking, the laws of physics break down at that threshold – not only are matter & energy destroyed, but so is the concept of “time” itself: > Therefore, not only does the black hole shred your body into tiny ribbons, your consciousness _freezes_ at that moment when Time collapses – your mind becomes forever trapped in a state of infinite anguish, pain, and desperation, where no man or god can save you. Death is not an option – because, from your perspective, Time itself no longer exists. > > Compared to that potential fate, I’d rather be eaten by Cujo. :eek: Actually that isn’t quite correct. For a large enough black hole you wouldn’t even know you crossed the event horizon until you tried to get out. It’s only in the singularity where time and space switch places. By the time you get there you’ve been pretty much cooked, irradiated, shredded, and torn into your component atoms anyway. A smaller black hole, you would most likely be killed before you even reach the event horizon by other debris circling the drain. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [January 19, 2011, 3:49pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/13 "2011-01-19T15:49:33Z")
My understanding is that Io is smack in the middle of Jupiter’s enormously strong radiation belt, and that you’d be exposed to nuclear-reactor levels of radiation. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [January 19, 2011, 4:27pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/14 "2011-01-19T16:27:23Z")
> [@Lumpy](#): > > My understanding is that Io is smack in the middle of Jupiter’s enormously strong radiation belt, and that you’d be exposed to nuclear-reactor levels of radiation. While the radiation would indeed be strong I don’t think it would be anywhere near that level. Is it possible you’re confusing the radiation levels you’d see in the wake of a nuclear accident, like Chernobyl, with the levels inside a reactor? Looking outside the solar system, we have magnetars with magenetic fields strong enough to WIPE YOUR BRAIN, supernovae capable of devestating planets from hundred of light years away, and jets from Quasars which are effectively death rays tens of thousands of light years long. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [January 19, 2011, 4:43pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/15 "2011-01-19T16:43:30Z")
> [@Finagle](#): > > Surface of Jupiter might be a contender as well. It’s a long way down and possibly just liquid metallic hydrogen. So you’d have tremendous pressure, cold, and possibly even massive lightning bolts to contend with due to the metallic nature of the core. > > Surface of Mercury gets up to 800 degrees F on one side and down to -300 on the other. So yeah, probably not a winner as you’d manage a second or two of unendurable agony for the former, and, if you believe Larry Niven, an eternity of superconducting awareness in the latter. Nitpicky: Mercury rotates. Larry Niven got it wrong, however, he knew that. The problem was that the discovery was made literally between the time he wrote the story and the time when it was accepted for publication. Bad luck for him. He requested from the editor the chance to revise his story but they said it wasn’t necessary. ---
**Author:** ![Mr.Kobayashi](https://avatars.discourse-cdn.com/v4/letter/m/4af34b/32.png) [@Mr.Kobayashi](https://boards.straightdope.com/u/Mr.Kobayashi)\ **Post date:** [January 19, 2011, 5:25pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/16 "2011-01-19T17:25:19Z")
Nice to see that lil ol’ Terra can hold her own when compared to the big boys in the lethality stakes. What about Europa - have we any clue how deep the oceans under the frozen surface might be? Or if the pressure could compete with the Marianas Trench…in 1960 for 20 mins? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 19, 2011, 5:46pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/17 "2011-01-19T17:46:21Z")
> [@](#): > > Actually that isn’t quite correct. For a large enough black hole you wouldn’t even know you crossed the event horizon until you tried to get out. It’s only in the singularity where time and space switch places. By the time you get there you’ve been pretty much cooked, irradiated, shredded, and torn into your component atoms anyway. Actually, the event horizon is where time and space switch places (that is to say, t becomes a spacelike coordinate and r becomes a timelike coordinate), but they do so in a locally-smooth way, so the point remains that it wouldn’t actually be particularly noticeable. And there is some point (either inside the horizon or out of it, depending on the hole’s mass) where you’d be spaghettified, so death-by-singularity isn’t actually an issue: The singularity is just a hard upper bound for how long anything could possibly survive. That is to say, the point of spaghettification depends on things like material strengths, but for any material at all, even unobtanium of some sort, it must be somewhere before the singularity. ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [January 19, 2011, 6:08pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/18 "2011-01-19T18:08:38Z")
> [@Mr.Kobayashi](#): > > What about Europa - have we any clue how deep the oceans under the frozen surface might be? Or if the pressure could compete with the Marianas Trench…in 1960 for 20 mins? See, I’d think that the pressure would be the _least_ of our worries if we were to attempt a landing there. Any other worlds, might as well try it - but Europa? ---
**Author:** ![fuzzypickles](https://avatars.discourse-cdn.com/v4/letter/f/9d8465/32.png) [@fuzzypickles](https://boards.straightdope.com/u/fuzzypickles)\ **Post date:** [January 19, 2011, 6:23pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/19 "2011-01-19T18:23:26Z")
> [@Mr.Excellent](#): > > See, I’d think that the pressure would be the _least_ of our worries if we were to attempt a landing there. Any other worlds, might as well try it - but Europa? I was gonna ask if you meant the _2010_ version or the _Ender’s Game_ version, but it doesn’t matter – either way, your unauthorized craft would be vaporized on sight. 🆒 ---
**Author:** ![Sparky812](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Sparky812](https://boards.straightdope.com/u/Sparky812)\ **Post date:** [January 19, 2011, 6:24pm UTC](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184/20 "2011-01-19T18:24:28Z")
Shouldn’t the OP read “On which planet/moon would you be vaporized faster?” [Next page](https://boards.straightdope.com/t/planet-moon-most-inhospitable-to-humans/568184.md?page=2)