-135.8°!

[Bob Juch]

A new look at NASA satellite data revealed that Earth set a new record for coldest temperature, as recorded by satellite. It happened in August 2010 when it hit -135.8 degrees. Then on July 31 of this year, it came close again: -135.3 degrees.

http://www.usatoday.com/story/weather/2 ... d/3950019/

[BackInTex]

That causes some serious shrinkage just thinking about it.

[themanintheseersuckersuit]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

[silverscreenselect]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

That explains the really thick fog we had that day.

[smilergrogan]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

[Bob Juch]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

But if it ever gets down to −346°F then the nitrogen will freeze.

[BackInTex]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

Yeah, that's what I was thinkng, too.

[Bob78164]

Carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78.5 °C (−109.3 °F; 194.7 K)

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

Thanks. I hadn't realized that could happen. --Bob

[Bob Juch]

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

Thanks. I hadn't realized that could happen. --Bob

What he mentioned but didn't make clear is that Earth's normal atmosphere is just 0.04% CO2. Many people don't know it's just 21% oxygen.

[BackInTex]

This doesn't mean that CO2 will start freezing out of the air when the air temp is below -78.5 C, because that depends on the partial pressure of CO2 in the air. If the relative "humidity" of CO2 was 100% it would be true, but at -78.5 C, where the saturation vapor pressure of CO2 is 1 atmosphere (since that's the normal sublimation point), and the actual partial pressure of CO2 is only about 400 parts per million, the relative "humidity" is only 0.04%. This means the frost point will be far below -78.5 C. Compare to water, where for a 0.04% relative humidity in air at 0C, the frost point calculates to about -70 C.

Thanks. I hadn't realized that could happen. --Bob

What he mentioned but didn't make clear is that Earth's normal atmosphere is just 0.04% CO2. Many people don't know it's just 21% oxygen.

How much of tht 21% is really dioxygen? Is there any naturally occuring pure oxygen?

[Bob Juch]

Thanks. I hadn't realized that could happen. --Bob

What he mentioned but didn't make clear is that Earth's normal atmosphere is just 0.04% CO2. Many people don't know it's just 21% oxygen.

How much of tht 21% is really dioxygen? Is there any naturally occuring pure oxygen?

If you mean O instead of O2, there must be an occasional free atom but only until it finds another one and binds to it.

[Bob Juch]

Just saw this:

Scientists discover Earth's 'most powerful' greenhouse gas to date

A new greenhouse gas that is 7,000 times more powerful than carbon dioxide at warming the earth has been discovered by researchers in Canada.

The gas, perfluorotributylamine, has been in use by the electrical industry since the middle of the 20th century.

The chemical, which does not occur naturally, breaks all records for potential impacts on the climate, said the researchers at the University of Toronto's department of chemistry.

"We claim that PFTBA has the highest radiative efficiency of any molecule detected in the atmosphere to date," said Angela Hong, one of the co-authors.

The study, published in the journal Geophysical Research Letters, found PFTBA was 7,100 times more powerful at warming the earth over a 100-year time span than CO {-2}.

However, concentrations of PFTBA in the atmosphere are low - 0.18 parts per trillion in the Toronto area - compared to 400 parts per million for carbon dioxide.

Drew Shindell, a climatologist at Nasa's Goddard Institute for Space Studies, said: "This is a warning to us that this gas could have a very, very large impact on climate change - if there were a lot of it.

"Since there is not a lot of it now, we don't have to worry about it at present, but we have to make sure it doesn't grow and become a very large contributor to global warming."