# How high a mountain can humans climb unassisted? **URL:** \ **Category:** Factual Questions\ **Created:** [April 24, 2018, 5:50pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054 "2018-04-24T17:50:40Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![Delicious](https://avatars.discourse-cdn.com/v4/letter/d/dbc845/32.png) [@Delicious](https://boards.straightdope.com/u/Delicious)\ **Post date:** [April 25, 2018, 2:01pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/21 "2018-04-25T14:01:34Z")
> [@Machine\_Elf](#): > > …50% of normal earth gravity: > sea level pressure 7.35 psi, Everest summit pressure 8.21 psi… Now ah’m just simple folk, not no fancy city physicist but it seems to me that air pressure should be lower all up on top o’ that big ol’ Hill yonder than down by tha seashore. ---
**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:** [April 25, 2018, 2:07pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/22 "2018-04-25T14:07:30Z")
Something has to be wrong with those numbers. I can see the general principle of decreasing g leading to an increase in pressure at Everest, but the 50% number can’t be right: There’s no way you could possibly have a higher pressure at Everest than at the surface. As for performance-enhancing drugs and medical treatments, it’s possible that they just act by replicating the effects of the natural adaptations. One of the high-altitude adaptations, for instance (though I can’t remember if it’s an Andean or a Himalayan one) is a naturally higher red-cell count. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 25, 2018, 2:11pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/23 "2018-04-25T14:11:41Z")
> [@Machine\_Elf](#): > > OK, I just modified my standard-atmosphere spreadsheet to allow for variable gravity. Here’s what I found. Is that calculating [scale](https://en.wikipedia.org/wiki/Scale_height) [height](http://lasp.colorado.edu/~bagenal/3720/CLASS2/2BaratropicLaw.html)? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 25, 2018, 4:09pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/24 "2018-04-25T16:09:00Z")
> [@Chronos](#): > > Something has to be wrong with those numbers. I can see the general principle of decreasing g leading to an increase in pressure at Everest, but the 50% number can’t be right: There’s no way you could possibly have a higher pressure at Everest than at the surface. Hey, I just report the numbers; it’s not my job to do a sanity check on this shit. :eek: Oh wait, yes, it IS my job. :smack: For all my different gravity scenarios, I kept sea-level pressure in the spreadsheet at 14.7 psi. The pressure for all other altitudes is derived incrementally from this starting point, so yes, even though I adjusted gravity, I ended up with screwball results at 29,000 feet. I ran through the spreadsheet again, this time adjusting sea-level pressure to the correct value for each gravity scenario. So here you go: 10x normal gravity: sea level 147 psi, Everest 0.001 psi 1x normal gravity: sea level 14.7 psi, Everest 4.58 psi 0.75x normal gravity: sea level 11.02 psi, Everest 4.596 psi 0.5x normal gravity: sea level 7.35 psi, Everest 4.103 psi So somewhere between 100% and 50% of normal gravity, there’s a point where the pressure at the summit of Everest is actually a smidge higher, despite sea-level pressure being lower. So for gravity within 50-100% of normal, you won’t get significantly more (or less) oxygen up there, but at least you’ll be able to climb slightly faster since you’ll weigh less. > [@Darren Garrison](#): > > Is that calculating scale height? Not that elegant. you specify sea-level pressure, and a temperature-versus-height profile for the entire atmosphere. It uses local pressure and temperature to calculate local density. The next line in the spreadsheet has a 100-foot elevation gain, and you use the previous line’s density to calculate how much lower the pressure is at that new altitude, and of course calculate a new density from that pressure and temperature. Repeat line after line, 100 feet at a time, until you’re at the summit of Everest. Some time ago I also extended it below sea level: the air pressure at the bottom of the [TauTona mine](https://en.wikipedia.org/wiki/TauTona_Mine) is somewhere 23 psi. ---
**Author:** ![blood63](https://avatars.discourse-cdn.com/v4/letter/b/97f17d/32.png) [@blood63](https://boards.straightdope.com/u/blood63)\ **Post date:** [April 25, 2018, 6:01pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/25 "2018-04-25T18:01:38Z")
So cool. Thanks for doing that. ---
**Author:** ![caligulathegod](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/caligulathegod/32/9685_2.png) [@caligulathegod](https://boards.straightdope.com/u/caligulathegod)\ **Post date:** [April 25, 2018, 6:11pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/26 "2018-04-25T18:11:30Z")
> [@Darren\_Garrison](#): > > From base to summit, [Mauna Kea is a good bit taller](https://www.azula.com/mauna-kea-worlds-tallest-mountain-mostly-underwater-2476365635.html). It’s listed as 15th highest prominence. Counting height from the ocean floor is like measuring penis length from the “taint”. ---
**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:** [April 25, 2018, 6:20pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/27 "2018-04-25T18:20:21Z")
Of course, in reality, the temperature-vs.-height profile would probably also be different, and a proper model ought to take that into account. I’d guess that the natural independent variables would be surface gravity, atmospheric column density (a measure of how much total gas there is), gas molecular mass, and insolation. For more detail, you might need to include things like multiple gases with different molecular masses, absorbtion spectra of the gases, and possibly even size and rotation rate of the planet. And at the highest level of detail, you’d need things like the layout of the continents. Of course, well before you got to that level of detail, you’d leave the realm of a first-order Excel spreadsheet and use a higher-order differential equations solver. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [April 25, 2018, 7:31pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/28 "2018-04-25T19:31:59Z")
> [@Chronos](#): > > …a planet that was capable of supporting taller mountains would probably have a lower surface gravity, which would probably make them easier to climb to any given height… Olympus Mons, anyone?: > **[Olympus Mons](https://en.wikipedia.org/wiki/Olympus_Mons)** > > Olympus Mons (/əˌlɪmpəs ˈmɒnz, oʊ-/; Latin for 'Mount Olympus') is a large shield volcano on Mars. It is over 21.9 km (13.6 mi; 72,000 ft) high as measured by the Mars Orbiter Laser Altimeter (MOLA), about 2.5 times the elevation of Mount Everest above sea level. It is Mars's tallest volcano, its tallest planetary mountain, and is approximately tied with Rheasilvia on Vesta as the tallest mountain currently discovered in the Solar System. It is associated with the volcanic region of Tharsis Olymp... [![](http://9buz.com/content/uploads/images/August2014/olympus_mons_on_mars_is_27km_tall_2014-05-11.jpg) ](http://9buz.com/content/uploads/images/August2014/olympus_mons_on_mars_is_27km_tall_2014-05-11.jpg) [![](https://image.spreadshirtmedia.com/image-server/v1/compositions/104469332/views/1,width=300,height=300,appearanceId=135,version=1452254899.jpg) ](https://image.spreadshirtmedia.com/image-server/v1/compositions/104469332/views/1,width=300,height=300,appearanceId=135,version=1452254899.jpg) ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [April 25, 2018, 7:55pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/29 "2018-04-25T19:55:53Z")
But Olympus Mons isn’t like mountains on Earth. Climbing it wouldn’t seem like climbing a mountain, it would seem like hiking for days up a very gentle slope. At the summit the base of the mountain would be beyond the horizon. I guess standing at a caldera edge would get you that “mountainy” feel, but you wouldn’t feel like you were on top of a mountain. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [April 25, 2018, 8:04pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/30 "2018-04-25T20:04:58Z")
> [@caligulathegod](#): > > It’s listed as 15th highest prominence. Counting height from the ocean floor is like measuring penis length from the “taint”. In one of his science essays, Isaac Asimov listed three different mountains as “earth’s tallest” depending on where you were measuring from.[ul] [li]Everest from the usual sea level[/li][li]Muana Kea from the base[/li][li]Kilimanjaro from the Earth’s center[/li][/ul] ---
**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:** [April 25, 2018, 8:16pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/31 "2018-04-25T20:16:00Z")
“Highest from the base” could also be one of the Andes, depending on how you define “base”. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 25, 2018, 8:31pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/32 "2018-04-25T20:31:23Z")
> [@caligulathegod](#): > > It’s listed as 15th highest prominence. Counting height from the ocean floor is like measuring penis length from the “taint”. Unless if you were to instantly drain the oceans Muana Kea would collapse from the lack of “water support” the base to summit counts. On land, the tallest mountain measuring from base to summit [is Mt. McDenali](https://futurism.com/mckinleydenali-the-tallest-land-based-mountain-on-earth-yes-taller-than-even-everest/). ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [April 25, 2018, 8:50pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/33 "2018-04-25T20:50:20Z")
> [@DesertDog](#): > > Kilimanjaro from the Earth’s center Actually, that’s [Chimborazo](https://en.wikipedia.org/wiki/Summits_farthest_from_the_Earth%27s_center). Kilimanjaro is tied for 5th. ---
**Author:** ![Delicious](https://avatars.discourse-cdn.com/v4/letter/d/dbc845/32.png) [@Delicious](https://boards.straightdope.com/u/Delicious)\ **Post date:** [April 25, 2018, 8:53pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/34 "2018-04-25T20:53:17Z")
> [@Elendil\_s\_Heir](#): > > Olympus Mons, anyone?: > > [Olympus Mons - Wikipedia](https://en.wikipedia.org/wiki/Olympus_Mons) > [http://9buz.com/content/uploads/images/August2014/olympus\_mons\_on\_mars\_is\_27km\_tall\_2014-05-11.jpg](http://9buz.com/content/uploads/images/August2014/olympus_mons_on_mars_is_27km_tall_2014-05-11.jpg) > [https://image.spreadshirtmedia.com/image-server/v1/compositions/104469332/views/1,width=300,height=300,appearanceId=135,version=1452254899.jpg](https://image.spreadshirtmedia.com/image-server/v1/compositions/104469332/views/1,width=300,height=300,appearanceId=135,version=1452254899.jpg) I imagine an unassisted climb would end badly ---
**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:** [April 25, 2018, 9:13pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/35 "2018-04-25T21:13:21Z")
More likely start badly. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [April 25, 2018, 9:17pm UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/36 "2018-04-25T21:17:56Z")
Just read the account of the expedition up [Rum Doodle](https://en.wikipedia.org/wiki/The_Ascent_of_Rum_Doodle). ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [April 26, 2018, 12:16am UTC](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054/37 "2018-04-26T00:16:03Z")
> [@Lemur866](#): > > But Olympus Mons isn’t like mountains on Earth. Climbing it wouldn’t seem like climbing a mountain, it would seem like hiking for days up a very gentle slope. At the summit the base of the mountain would be beyond the horizon. I guess standing at a caldera edge would get you that “mountainy” feel, but you wouldn’t feel like you were on top of a mountain. I don’t know what your starting point would be for trekking up Olympus Mons, but the trek up to the top of Mt. Everest is rather gradual as well. I started out in Kathmandu (4,000’) and took a five hour bus ride to Lamasungu (7000’). From there I hiked about _85 miles_ to reach the Everest Base Camp area (18000’). I did this in 18 days. Much of the trek is over quite level ground. Although there are some steep climbs along the way, one never has to use their hands to grab a rock or tree to pull up on. After EBC is when the real climbing begins. I had no interest in climbing to the top of Everest at all and walked the 20 miles back to the air strip in Lukla for a flight to Kathmandu. Most might consider climbing Mt Everest (29,000’) begins at Base Camp, but possibly don’t realize that the climb really _begins_ at 18000’ so one needs to “only” climb 11000 feet to get to the top. [Previous page](https://boards.straightdope.com/t/how-high-a-mountain-can-humans-climb-unassisted/813054.md?page=1)