The Jetson Conspiracy II

At and above the ozone layer, the atmosphere is quite thin. The one on top of Mt. Everest is thin enough – still having about 50 times more pressure than at Mars’s “sea level”.

Now, we all know that water freezes at 0° and boils at 100°C – that’s why Celsius was given these units at all, to fit water’s behavior.

At sea level.

Now, in the big picture, Mt. Everest is not very high – almost 9km. The top of the atmosphere is 12-20 times higher than that, depending on what your definition of atmosphere is; the center of the Earth is 700 times as deep; the moon 40,000 times as far away. These numbers are, of course, too big for our imagination, so I’ll focus on something not so far away: the ozone layer, 3.5 – 4 times as high up as Mt. Everest.

Now, back to water. On top of Mt. Everest, water would boil at about 70°, being still below the “armstrong limit”, which I’ll get to later. Meaning: If it were as hot on top of Mt. Everest as it is in the earth’s hottest deserts, water still wouldn’t spontaneously boil – up in the higher ranges of where intercontinental airplanes fly, however, we’re already down to 50°C to evaporate. Water would turn into a normal gas, never to condense again (if, that is, going up weren’t cooler). Just imagine pouring a glass of cold “Mountain Dew” in such an environment: First it would bubble out all of it’s CO2 like all carbonated drinks do, warming up the while and evaporating like in our daily experience here on earth’s surface. But then, if you don’t drink it fast enough, something funny begins to happen – the bubbles don’t get smaller as the drink goes flat, but bigger. Soon the drink begins to bubble away as if it were set on a burner. Only, the bubbles tend to come from the side and top of the glass more than from the bottom, for heat needed for boiling is extracted from all directions. And as soon as the drink is as warm as the air around it, it has already completely evaporated.

A human in such an environment, at least with a pressurized oxygen supply, would not experience this over 50°C weather as being so uncomfortable as on the earth’s surface, where his sweat takes too long to evaporate. For one’s built in “air conditioner” will work best in thin air (high altitude), because the sweat will evaporate quite quickly, taking heat away from the skin.

Watch out though. You’d have to be drinking not only an awful lot of water but also taking in all other substances like salt that are quickly sweated out. Gatorade, bananas and salt tablets are required. (And, since the air is so thin, oxygen bottles are needed as well.)

Or should we just say that we’re happy that the temperature outside of your international flight is usually well below 0° instead of above 70°C?

Twice as high as Everest’s peak, however, the problem becomes much more real. For that’s when water boils at below human body temperature. This means that the body and its mucous membrane tissue acts like a hot plate for its own sweat and other wet sources (e.g. tears). Water boils instantaneously, not evaporating slowly like we experience it down on the earth’s surface, irregardless of whether we use oxygen bottles or not or what temperature the air around us is. At such low pressures, the body experiences spontaneously boiling blood – not a nice prospect, to say the least.

And just to think that the danger of boiling blood be a mere 18 km away, only about 50% higher that the altitude of intercontinental flight. If we had a mountain on earth as high as Olympus Mons on Mars, there would surely be extreme sportsmen who would climb up there to experience a few seconds of boiling blood.

Now, for our Jetsons’ Colony (Yes, that’s the point of the post.) we’re still only half way to goal.

As we all know, temperature goes down as we go up in the atmosphere, right? Up where we fly the airplanes, it’s usually about -30° to -40°C. And it just keeps getting colder as we go up? Well, not always. In most of the atmosphere it does exactly the opposite. If you could float down from the IIS to the ground, you would first meet extremely hot air molecules, about 1000°C. But since the exosphere is not even thick enough to be called an atmosphere, this temperature doesn’t effect the things around it much (if there were anything there). Of course it creates drag on anything travelling at 10km/s trying to stay in orbit around the earth, but that’s independent of temperature.

This phenomenon turns around though where the “normal” atmosphere (Homosphere) begins at about 85km altitude – where –90°C weather reigns. Right above this is where space shuttles and meteors begin to glow, obviously not because the air is too hot but because of drag: friction causes heat.

Between 85km and 50km (going down), the temperature rises again, having its highest temperature at the top of the stratosphere. Here it is somewhat cooler (0°C) than at the earth’s surface but a good deal warmer than where your jet flies. Somewhere below this, the atmosphere, in the form of ozone, is thick enough to filter out a good deal of the UV light, creating these balmy temperatures.

So like the water in a like, the “natural” way for the atmosphere would be to be warmer at the top and get colder as one moves down. But light gets through the atmosphere millions of times better than it gets through water. There are really only two areas where the light is absorbed and turned into heat: in the ozone layer and on the earth’s surface. Both create an “inversion”, so that rising altitude means lower temperatures.

For life on earth, this situation is mandatory – not only because we prefer 15°C weather on the surface to –50°C – but because of the water cycle. Water evaporates into the air on the surface (especially the ocean surface) in small amounts but continuously. While rising, the pressure drops so that the water can remain evaporated a long way up. But the temperature drops on the way up much faster than the pressure, causing the water vapor to “look for” an opportunity to condense as clouds, rain and snow.

And condense it does.

Water vapor, which is 1/3rd lighter than normal air, would just keep rising up in our atmosphere, if it weren’t for the ultra cold layer from 10-25km. It would reach the upper atmosphere quickly enough, being broken down into its elements by the same ultraviolet light which makes the ozone layer. The oxygen would become the integral part of the atmosphere that it already is. The hydrogen on the other hand would sooner or later escape out into space, being blown off by solar winds and being sucked up eons later by Jupiter, the sun or by another gaseous body – or just leaving solaria all together.

Clouds, rain, snow – all the things we take for granted and see as being normal – these are just the results of the cold air barrier between us and the upper atmosphere. As a result, the stratosphere is horridly “dry”.

And because of this barrier, life can exist on earth. And significant amounts of hydrogen can stay bound to the earth, in its atmosphere, especially in the form of water. Well, maybe it’s time to put this cosmically natural, wondrous phenomenon to work for us.

Curious? Me too;-)