Mount Everest is our highest mountain and it seems barely reachable on a human level. Even with oxygen assistance, many climbers have either perished or turned back. Apparently, about 200 climbers have accomplished the climb without additional oxygen. I wonder if anyone has ever considered an Earth with an unclimbable mountain. How high would it be? Have any existed on the Earth in the past?
How much do oxygen levels decrease at an altitude beyond
Everest?
If you can bring additional oxygen and a pressure suit, and other life support, the limit may be cosmic radiation beyond the van Allen belts… Able to shield from those too, well then you have the issue that humans only live so long. Including reproducing along the way, with appropriate medical care, no real upper limit because they will always be a bit higher the next day.
How is any of this relevant to unassisted mountain climbing?
Your question seems to be mostly about human capacity, which I can’t say much about, but it’s worth mentioning that geologically, Everest is about as tall as it’s possible for a mountain to be on Earth. And 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.
There’s also a question, not only of a mountain’s height, but of its shape. Some mountains can be “climbed” by simply hiking to the top, while others require scaling shear rock faces.
Without straying afield here, it sounds like your meaning of “unassisted” is “no oxygen tanks”. Google says this:
So, that would have to be it, yes?
Note that compressed air would do nothing for you - unless breathed within some sort of compression chamber.
Not sure what this means. The “death zone” of high-altitude mountaineering doesn’t mean “instant death.” People do linger there, albeit not indefinitely.
Given that people have just barely climbed Everest without supplemental O2, I would imagine that trying to climb much higher would increase the odds of death (either from illness, or from misadventure due to hypoxic mental faculties) to the point that no one would want to try it (sort of like free-diving to 1000 feet of depth).
Camp 4 is right on the edge of the death zone, ~3000 feet below the summit. AIUI it’s an all-day affair to summit from Camp 4 and then get back down to Camp 4. I don’t imagine you could have a “Camp 5” any higher, since it’d be in the death zone and you’d be slowly dying while you try to rest there. So you’d be trying to summit a hypothetical higher-than-Everest peak from the same camp 4. Another 1000 feet of elevation increases your summit attempt time from that location by 33%. I’m not even sure that would be possible.
200 some people may have gotten to the top of Everest without supplemental oxygen, but the fact that they made it and returned doesn’t mean they weren’t at or very close to the very physical limits of human ability. Any altitude higher than 8000 m is incompatible with human life, period. Consider that the maximum limit of permanent human survivability is 5500 m.
Also, like doing push-ups, you haven’t “climbed a mountain” until you’ve both gone up and come back down.
There are also various mutations that make it easier to survive and climb at altitude. The Sherpa population in Nepal and Tibet have a variety of biochemical adaptations that make them capable of climbing higher and with fewer debilitating side effects.
Some of the best western climbers like Reinhold Messner many have also had these genes which allowed them to operate at altitude much better than the average climber. Gradual acclimatization only goes so far, and at high altitude it’s just a race between building hemoglobin and your body eating itself. The Sherpa have better odds.
And some climbers, especially the Sherpa, can actually operate fairly well at that altitude for a reasonable period of time. If there were higher peaks they could climb them.
Plus, the people of the Andes also have adaptations to high altitude, but it’s a different set of adaptations than the Sherpa have. One can imagine a descendant of both populations lucking out and getting both sets of adaptations, and possibly surviving even higher than either.
Also take a gun, in case you meet the Buddha.
I remember a National Geographic detailing how Messner climbed Everest alone…without supplemental oxygen.
You could take one of these super-climbers and do that athletics doping thing where they remove some blood then get the red cells put back in later to give them more oxygen capacity in their blood.
Are there any performance-enhancing drugs you could pump them full of that would help with climbing mega-Everest?
Seems to me that a planet with lower surface gravity would also have lower atmospheric pressure, making those taller mountains more inaccessible.
Diamoxis the standard drug taken to help with high altitude acclimatization, but I’m not sure if it would be helpful to folks with the genetic adaptations.
Yes, but the lifeforms that evolve on such a planet would be used to the lower atmospheric pressure, so it may cancel out.
From base to summit, Mauna Kea is a good bit taller.
Surface gravity and atmospheric pressure aren’t rigidly locked together. For examples, see Earth and Venus.
For low gravity and high atmospheric pressure you need more atmospheric mass. Venus has that.
If we’re talking about a hypothetical planet that has lower gravity than earth, but the same total atmospheric mass (i.e. 14.7 pounds of mass above every square inch of the planet’s surface), I’m not certain what would happen to the atmospheric pressure profile. It would be lower at the surface, but that also means that the rate-of-decrease with altitude would be less; the atmosphere would be taller. To know what the new atmospheric pressure would be at any altitude other than sea level, I think you’d have to make a spreadsheet model of the atmosphere.
If you’re not quite convinced of this, then imagine taking things far, far in the opposite direction. Imagine a planet with ten times earth gravity, but same atmospheric mass. Sea-level pressure would be 147 psi, and there wouldn’t be much air mass remaining at the summit of Everest; pressure there would certainly be lower.
OK, I just modified my standard-atmosphere spreadsheet to allow for variable gravity. Here’s what I found.
normal earth gravity:
sea level pressure 14.7 psi, Everest summit pressure 4.58 psi.
75% of normal earth gravity:
sea level pressure 11 psi, Everest summit pressure 6.13 psi
50% of normal earth gravity:
sea level pressure 7.35 psi, Everest summit pressure 8.21 psi.
And going in the opposite direction, 10 times normal earth gravity:
sea level pressure 147 psi, Everest summit pressure 0.0001 psi.
So, assuming you are able to reduce the gravity on the earth, you’d definitely have an easier time climbing Everest without supplemental O2. Not just less exertion, but more air. We should look into making this happen. 