If the atmosphere disappeared

[Silver007A]

Hi All,

 

I have a hypothetical question and apologise in advance for my layman’s language.

 

If half of the Earth’s atmosphere suddenly disappeared, would the other half become unstable?

 

I would imagine so and would therefore like to also ask for your ideas on the following-

 

How long would the other half of the atmosphere take to collapse?

 

How long would air be available for us to breathe?

 

Thanks you so much

[CaptainPanic]

Ok - funny question. Writing a sci-fi book or something?

 

If you suddenly remove half the atmosphere (let's say the northern half - the entire northern hemisphere's atmosphere), then the atmosphere on the southern hemisphere would rush north to compensate.

 

At first, the oceans in the north would boil, but when the air from the southern atmosphere would reach the north, that would stop. I have no way to estimate how long that would take, but we're talking minutes to hours, no more - long enough to suffocate. It would be quite a storm though, with windspeeds higher than ever.

 

Afterwards, the overall pressure would be only 0.5 atm, instead of the 1 atm we have now. The initial massive decompression would cool the atmosphere by a good 70 degrees to -50 Celsius (this is a rough approximation!!). I think that also, in this decompression all the water in the atmosphere would condensate or sublimate (form water droplets or ice crystals), so you get a lot more clouds.

 

After a little while, the sun would surely heat the atmosphere again (rough estimate is that this would take about 3 weeks), and these clouds would disappear. A little more water would evaporate, but nothing significant. I don't think that the sea water levels would change much because of it. But during those few cold weeks, the climate would be quite different. Perhaps it could change forever. That could have long lasting implications.

 

If you can survive the initial complete vacuum in the north, then I think you can survive the whole thing actually. 0.5 bar is enough for people. 0.5 bar is the pressure you find between 5 and 6 kilometers altitude. It would take some getting used to, but you can survive there. We'd be tired all the time though.

[StringJunky]

Ok - funny question. Writing a sci-fi book or something?

 

If you suddenly remove half the atmosphere (let's say the northern half - the entire northern hemisphere's atmosphere), then the atmosphere on the southern hemisphere would rush north to compensate.

 

At first, the oceans in the north would boil, but when the air from the southern atmosphere would reach the north, that would stop. I have no way to estimate how long that would take, but we're talking minutes to hours, no more - long enough to suffocate. It would be quite a storm though, with windspeeds higher than ever.

 

Afterwards, the overall pressure would be only 0.5 atm, instead of the 1 atm we have now. The initial massive decompression would cool the atmosphere by a good 70 degrees to -50 Celsius (this is a rough approximation!!). I think that also, in this decompression all the water in the atmosphere would condensate or sublimate (form water droplets or ice crystals), so you get a lot more clouds.

 

After a little while, the sun would surely heat the atmosphere again (rough estimate is that this would take about 3 weeks), and these clouds would disappear. A little more water would evaporate, but nothing significant. I don't think that the sea water levels would change much because of it. But during those few cold weeks, the climate would be quite different. Perhaps it could change forever. That could have long lasting implications.

 

If you can survive the initial complete vacuum in the north, then I think you can survive the whole thing actually. 0.5 bar is enough for people. 0.5 bar is the pressure you find between 5 and 6 kilometers altitude. It would take some getting used to, but you can survive there. We'd be tired all the time though.

 

Would the Earth system restore the pressure eventually to previous levels?

Edited July 24, 2012 by StringJunky

[CaptainPanic]

Would the Earth system restore the pressure eventually to previous levels?

I don't think so. Our atmosphere is 80% nitrogen, which is not stored in huge quantities anywhere else (not in the oceans, not in rocks either). So, remove half of that, and it's just gone.

[StringJunky]

I don't think so. Our atmosphere is 80% nitrogen, which is not stored in huge quantities anywhere else (not in the oceans, not in rocks either). So, remove half of that, and it's just gone.

 

OK, cheers.

[Bill Angel]

 

Afterwards, the overall pressure would be only 0.5 atm, instead of the 1 atm we have now. ...

 

If you can survive the initial complete vacuum in the north, then I think you can survive the whole thing actually. 0.5 bar is enough for people. 0.5 bar is the pressure you find between 5 and 6 kilometers altitude. It would take some getting used to, but you can survive there. We'd be tired all the time though.

 

But what would people eat? How much vegetation could thrive in an atmosphere equivalent to the current atmosphere at an altitude of 5 Km? And would there be enough of an Ozone layer to block UV radiation from the Sun?

Edited July 24, 2012 by Bill Angel

[Silver007A]

Ok - funny question. Writing a sci-fi book or something?

 

If you suddenly remove half the atmosphere (let's say the northern half - the entire northern hemisphere's atmosphere), then the atmosphere on the southern hemisphere would rush north to compensate.

 

At first, the oceans in the north would boil, but when the air from the southern atmosphere would reach the north, that would stop. I have no way to estimate how long that would take, but we're talking minutes to hours, no more - long enough to suffocate. It would be quite a storm though, with windspeeds higher than ever.

 

Afterwards, the overall pressure would be only 0.5 atm, instead of the 1 atm we have now. The initial massive decompression would cool the atmosphere by a good 70 degrees to -50 Celsius (this is a rough approximation!!). I think that also, in this decompression all the water in the atmosphere would condensate or sublimate (form water droplets or ice crystals), so you get a lot more clouds.

 

After a little while, the sun would surely heat the atmosphere again (rough estimate is that this would take about 3 weeks), and these clouds would disappear. A little more water would evaporate, but nothing significant. I don't think that the sea water levels would change much because of it. But during those few cold weeks, the climate would be quite different. Perhaps it could change forever. That could have long lasting implications.

 

If you can survive the initial complete vacuum in the north, then I think you can survive the whole thing actually. 0.5 bar is enough for people. 0.5 bar is the pressure you find between 5 and 6 kilometers altitude. It would take some getting used to, but you can survive there. We'd be tired all the time though.

 

Thanks, and yes