At the bottom of the Marianas trench.

[cubby]

You don't need to go deep to test that...

I was just asking - my knowledge base for this is next to zero. It would seem, however, that without the pressure of water, the air density wouldn't be enough to crush your eardrums. That's why I was asking if we'd been that deep, or close to it. From what I've seen we've only be 7 miles down, and that was with a drill.

[Puupi]

You've been arguing this point across several pages now. I don't know why you don't realise intuitively that the temperature at which water boils is not conducive to continued human life. Even so, you should've done a bit of investigation into the actual facts:

http://www.livescience.com/34128-lim...-survival.html

At 60C with 100% humidity most humans are dead in 10 minutes. At low humidity levels you might last 10 hours.

Yes, well we aren't talking about 100% humidity here.

At 100C, even at low humidity levels, you'll be lucky to last more than few minutes. Maybe you're thinking Fahrenheit? (which would be about 38C)

.....Fahrenheit....really?

FYI, I have spent some time Saudi Arabia. It is common knowledge there that exposure to temperatures above 60C (and it is very dry there) will quickly start killing people. 100C is very dangerous to an unprotected human.

Long term heat exposure is very different from a brief sauna visit. Also, you just said

At 60C with 100% humidity most humans are dead in 10 minutes. At low humidity levels you might last 10 hours.

So which one is it?

I've spent an hour to three hours in 100C about 1000 times in my life. Still here.

[willtron]

If it was just an empty chasm going down, the air pressure would increase.

Assume air at sea level at 15°C then the air would have a density of 1 atmosphere. At -11,000m it would be about 3.21 Atmospheres.

Furthermore, there would be the temperature increase - the Kola Superdeep Borehole - was drilled to ~12,000m and reached 180°C. (there are deeper but their temperatures at depth aren't listed). Normally the geothermal gradient is 25 °C per km of depth away from tectonic and seismic zones, seeing as the trench is part of a subduction zone this isn't too pertinent, but it gives you an idea.

You would notice a difference.

[cubby]

I've spent an hour to three hours in 100C about 1000 times in my life. Still here.

Learned something new (again) here - thanks. Thought you were crazy to say that, but then EDUCATION! and now I'm smarter (well, maybe that's going too far . . .).

In what circumstances were you at 100C+? Just curious.

[Puupi]

That room does not have a temperature anywhere near 100°C.
You obviously do not know what you are talking about.
You endanger yourself this way using a sauna without supervision while not knowing how to behave and why.

Oh please, just drop it. You have no clue what you are talking about.







These are all public saunas in Finnish swimming halls.

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Learned something new (again) here - thanks. Thought you were crazy to say that, but then EDUCATION! and now I'm smarter (well, maybe that's going too far . . .).

In what circumstances were you at 100C+? Just curious.

In a sauna, like all Finnish people. There is nothing dangerous in being in a 100C sauna for an hour. Of course it's a strain on your body and can be exhausting just like any other physical activity. But it's not inherently dangerous. Sure, if you are pregnant you shouldn't stay 1 hour at 100C, or if you have heart problems, or you are very old etc.

Just like you shouldn't run 5 miles either if have any of those conditions. A question to those who have questioned the safety of being in a sauna: is running or going to the gym considered dangerous?

[willtron]

Oh yeah, like this?

<snip>

I, and every other Finnish person, can only just double facepalm at you.

I'm not Finish, but can I still single facepalm?

[Puupi]

I'm not Finish, but can I still single facepalm?

Sure, even double! Or triple if someone lends you a hand!

[cubby]

In a sauna, like all Finnish people. There is nothing dangerous in being in a 100C sauna for an hour. Of course it's a strain on your body and can be exhausting just like any other physical activity. But it's not inherently dangerous. Sure, if you are pregnant you shouldn't stay 1 hour at 100C, or if you have heart problems, or you are very old etc.

Just like you shouldn't run 5 miles either if have any of those conditions. A question to those who have questioned the safety of being in a sauna: is running or going to the gym considered dangerous?

That's pretty cool. I didn't know that extreme sauna'ing was a sport. Does it affect you relatively the same as a workout?

(and hey, I'm not the other guy - I bothered to do some minimal research and learned that people have survived 180C for VERY short periods of time - so 100C is just a walk in the park, er, sauna ).

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That room does not have a temperature anywhere near 100°C.
You obviously do not know what you are talking about.
You endanger yourself this way using a sauna without supervision while not knowing how to behave and why.

That room absolutely has a temperature of 100C. You need to do some research if you can't be bothered to listen to your betters.

Stop embarrassing yourself.

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If it was just an empty chasm going down, the air pressure would increase.

Assume air at sea level at 15°C then the air would have a density of 1 atmosphere. At -11,000m it would be about 3.21 Atmospheres.

Furthermore, there would be the temperature increase - the Kola Superdeep Borehole - was drilled to ~12,000m and reached 180°C. (there are deeper but their temperatures at depth aren't listed). Normally the geothermal gradient is 25 °C per km of depth away from tectonic and seismic zones, seeing as the trench is part of a subduction zone this isn't too pertinent, but it gives you an idea.

You would notice a difference.

Does the geothermal gradient changed based on the width of the drill? So, for instance, if we did drain the Marianas Trench - it would be much wider than a drill bit, so would the access to more air affect the temperature?

[willtron]

That's pretty cool. I didn't know that extreme sauna'ing was a sport. Does it affect you relatively the same as a workout?

(and hey, I'm not the other guy - I bothered to do some minimal research and learned that people have survived 180C for VERY short periods of time - so 100C is just a walk in the park, er, sauna ).

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That room absolutely has a temperature of 100C. You need to do some research if you can't be bothered to listen to your betters.

Stop embarrassing yourself.

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Does the geothermal gradient changed based on the width of the drill? So, for instance, if we did drain the Marianas Trench - it would be much wider than a drill bit, so would the access to more air affect the temperature?

The heat is from the pressure and isotopes within the rocks. The geothermal gradient itself is a set thing, it exists whether we drill or not. As far as ambient air temperature goes, think of it this way, when you fly on a plane and get to cruising altitude it's always cold AF outside, the same is true with increasing pressure, this increases the temperature of the air naturally.

There will still be a temperature delta (difference) though between the air and the rocks though. I.E the temperature of the rocks based on the geothermal gradient and the the air pressure will not be the same, so what will happen is over X period of time, it will locally cool to a stable temperature and just like the rest of the world, develop a microclimate from pressure cells based on different rates of heating and cooling of the land and the air.

So the direct answer is, the gradient won't change, however, the speed at which the temperature stabilises will be much quicker due to the larger surface area. A really small diameter borehole will actually retain its heat and won't really be impacted - it's how geothermal power and heating works.

How much the delta stabilsed temperature is, I can't say it could be 0.1 celcius, it could be 10 celcius.

[Puupi]

That's pretty cool. I didn't know that extreme sauna'ing was a sport. Does it affect you relatively the same as a workout?

(and hey, I'm not the other guy - I bothered to do some minimal research and learned that people have survived 180C for VERY short periods of time - so 100C is just a walk in the park, er, sauna ).

Well 100C for an hour is not extreme sauna'ing. It's just normal relaxation.... like taking a walk. It doesn't affect your muscles like a workout, but puts a strain on your metabolism.

The extreme sauna'ing as a sport, which had those world championships and all (haven't been held since 2010 when two of the finalists died), is bat shit crazy. They are literally boiling themselves to death.

[Annoying]

Saunas don't use dry air?

I go to sauna like once or twice a week. I heat it up to 100C. And it's definitely DRY before I throw water on the stones. It's not going to damage you in any way.

80C is a completely normal temperature for a sauna... for like 10min. You could sit in 100C for a few minutes with no issues. I and the other people doing math in here are assuming that you're staying down in the trench for a long while, though. It appears that you'd die from heat or oxygen toxicity after a while.

A good example:
https://en.wikipedia.org/wiki/Cave_of_the_Crystals

The cave is extremely hot, with air temperatures reaching up to 58 °C (136 °F) with 90 to 99 percent humidity. The cave is relatively unexplored due to these factors. Without proper protection, people can only endure approximately ten minutes of exposure at a time.

With it being 100C, there would be challenges getting out of the trench in time to not die. The oxygen toxicity doesn't have the same issue, as that's on a scale of hours to days.

Given, you could bring a shitload of water with you and do alright. As long as it's in a container preventing it from boiling. Being that 100C is boiling point of water.

[Shaderas]

80C is a completely normal temperature for a sauna... for like 10min. You could sit in 100C for a few minutes with no issues. I and the other people doing math in here are assuming that you're staying down in the trench for a long while, though. It appears that you'd die from heat or oxygen toxicity after a while.

A good example:
https://en.wikipedia.org/wiki/Cave_of_the_Crystals

I was going to say it, but Annoying (the mod above me) said it first. Most saunas I have been in operate around 80 degrees celsius at the top end. Obviously, your experiences may vary though...

[Kellhound]

That's incorrect, actually. With current materials we could build a military sub that can operate at 2km down. It would just be far too expensive with too little additional benefit for them to go down that path.

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Saunas don't use dry air and the majority of people use them at 80C... soo, yeah. Hell, according to the Finnish Sauna Society pregnant women shouldn't exceed 70C. I'd love to see where you got your info on immediate lung damage from moist air above 122°F...

The deepest diving military sub class suffered significant damage to its systems below 500m even though its crush depth exceeded 1300m. Building a sub that can withstand routine sub 1km dives and is combat capable is not possible because of space constraints.

[Annoying]

I was going to say it, but Annoying (the mod above me) said it first. Most saunas I have been in operate around 80 degrees celsius at the top end. Obviously, your experiences may vary though...

I mean, the record is 16min at 110C, and those people prepare themselves by extreme hydrating. Most people will faint after about 6min, and staying in longer than 3min at that temperature results in burns on the skin. In 2013, both competitors who made it to the finals in a competition in Finland fainted at the 6min point, and one of them died.

[Donald Hellscream]

The air would be very dry and very hot, one would likely perish in a matter of hours with no water available.

[Puupi]

I mean, the record is 16min at 110C, and those people prepare themselves by extreme hydrating. Most people will faint after about 6min, and staying in longer than 3min at that temperature results in burns on the skin. In 2013, both competitors who made it to the finals in a competition in Finland fainted at the 6min point, and one of them died.

You do realize it's not the 110C basic heat that's killing them? It's that they are constantly pouring water on the stove (half a litre every 30 seconds, that's brutal). It's the humidity and the boiling steam fume that's nasty - not the dry 110C heat.

And it was 2010 when that death happened. Also, they weren't the only ones competing, they were just the last two remaining in the room.

[Annoying]

You do realize it's not the 110C basic heat that's killing them? It's that they are constantly pouring water on the stove (1 litre every 30 seconds, that's brutal). It's the humidity and the boiling steam fume that's nasty - not the dry 110C heat.

And it was 2010 when that death happened. Also, they weren't the only ones competing, they were just the last two remaining in the room.

And...?

People have died in 100C saunas. Yes, the more humidity you add, the worse it is. In water, a human can only survive ~40C long term. In completely dry air, though, no human can survive more than ~70C long term. It's great to argue about saunas, but they are short term things. You can't sit in a 100C sauna of completely dry air for more than a timespan of minutes. Maybe an hour if you're used to it and have water at a cooler temperature.

We're talking about walking down to the trench, meaning you have to walk out. You're not getting below 70C, the point at which you might survive long term, before you die.

[Moratori]

And...?

People have died in 100C saunas. Yes, the more humidity you add, the worse it is. In water, a human can only survive ~40C long term. In completely dry air, though, no human can survive more than ~70C long term. It's great to argue about saunas, but they are short term things. You can't sit in a 100C sauna of completely dry air for more than a timespan of minutes. Maybe an hour if you're used to it and have water at a cooler temperature.

We're talking about walking down to the trench, meaning you have to walk out. You're not getting below 70C, the point at which you might survive long term, before you die.

40C? Really? How warm is the water in a normal bath when it's just at the point where it's burning?

[Annoying]

40C? Really? How warm is the water in a normal bath when it's just at the point where it's burning?

Long term. Important words. Humans can handle much higher in the short term, and bath water drops to an acceptable temperature pretty quickly. Not to mention you get out of the bath before it's going to do anything to you. Like saunas, baths are short term things. They even cool down.

[Raelbo]

.....Fahrenheit....really?

Ok I'll concede that point. Having spent some time now reading up on Saunas and the Finnish practice, I am now a bit more aware of where you are coming from. And yes, I get it, people acclimated to using Saunas can survive relatively brief exposure to those temperatures within the very controlled sauna environment (although even then, 100C seems to be fairly hardcore for sauna users).

The problem with your argument is that you're trying to generalise a very specific scenario (ie constrained to a small group of people in a very specific environment) to the scenario in this thread. Which is why it makes no sense to anyone else. It's like trying to argue that because Fakir's in India can walk over hot coals, people would be unaffected if the surface of the planet turned into molten slag.

Long term heat exposure is very different from a brief sauna visit.

And I think that is the crux of the argument. This thread isn't about a controlled sauna environment with:

• Zero wind factor (which would destroy the body's ability to build a small insulating layer of cool air around itself through perspiration)
• Almost zero humidity
• No human activity (ie people in the sauna aren't moving around)

Also, you just said

"temperatures above 60C (and it is very dry there) will quickly start killing people"
"At 60C with 100% humidity most humans are dead in 10 minutes. At low humidity levels you might last 10 hours."

So which one is it?

The two statements are quoting different contexts. Let me highlight the differences (both stated and implicit):

ABOVE 60C (at unspecified, ie normal humidity levels) SOME people will die quickly.
AT 60C AND low humidity levels, you MIGHT last 10 hours.

The purpose of the first statement is to illustrate what happens to most humans above 60C in the natural environment.
The purpose of the second statement is to illustrate the extremes of what exceptional humans can potentially survive at 60C in an ideal environment.

Also you manage to entirely miss the point: Environmental temperatures above 60C pose a significant danger to human life. 100C is a lot hotter and therefore poses a much greater risk.

I've spent an hour to three hours in 100C about 1000 times in my life. Still here.

Good for you. Congrats on being among the most resilient members of our species when it come to surviving high temperatures. Most people wouldn't be able to do it, much like we can't run 100m in less than 10s.

And just because you can do this in a controlled sauna environment, even you would probably die very quickly if you were exposed to temperatures of 100C in a natural environment. Which is the whole point.

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40C? Really? How warm is the water in a normal bath when it's just at the point where it's burning?

At 65C water will give you 3rd degree burns in 2 seconds
At 60C water will give you 3rd degree burns in 5 seconds
At 55C water will give you 3rd degree burns in 30 seconds
At 50C water will give you 3rd degree burns in 3 minutes

I guess the exact temperature which we will find uncomfortable will vary from person to person, but I would guess that 45C will be painful to most people.