Noctilucent Clouds Spread and Mystify 227
Wired has a feature on noctilucent clouds, once seen only at high latitudes but increasingly visible now lower down the globe. The clouds result from ice crystals at altitudes of 50 miles, higher than five 9s of the atmosphere. What water ice is doing up there, in a region 100 million times drier than the Sahara desert, is only one of the mysteries associated with the clouds. They are a recent phenomenon: the first scientific description of noctilucent clouds was penned in 1885. For a time it was believed that the clouds were an effect resulting from the eruption of the Krakatoa volcano two years before. Since 2002, the clouds have been sighted — and photographed — as far south as Oregon, Colorado, and Utah. Some scientists believe that human-caused climate change is playing a role, but others doubt this. Two satellites are in orbit to study the clouds; NASA's AIM generated this day-by-day movie of clouds in the vicinity of the North Pole during 2008.
Dry? (Score:2, Insightful)
"What water ice is doing up there, in a region 100 million times drier than the Sahara desert"
Bloody well isn't dryer than Mars and Mars has clouds and precipitation.
I'm in... (Score:4, Insightful)
Just a wee bit sad. (Score:4, Insightful)
Kinda disappointing that the first thing nowadays when people see something new it's that "Wow, humans really stuffed up the planet" instead of "Wow, that's an interesting natural phenomenon"
Re:Well there can be only one answer.... (Score:4, Insightful)
Otherwise, it's a closed system and there's no net change in temperature.
You know, except for that whole sun thing.
Space Shuttle? (Score:4, Insightful)
Aren't they caused by the space shuttle? I could swear there was an article a couple weeks ago on slashdot about it. Basically they found that they tend to form hours after the shuttle launch, particularly around Antarctica. The shuttle's boosters release X tons of water into the high atmosphere, at altitudes water can't regularly attain, which gets caught by high moving winds that drive it south, where they crystallize.
Interestingly enough we just had a shuttle launch just a couple days ago.
Re:Ice Age (Score:3, Insightful)
It's probably better to say that global warming was the getting out of the ice age. The climate got warmer, wetter, and less icy. The problem is we really have no idea what drove that global warming -- other than it was not the accumulation of greenhouse gases.
I complete agree with that. Even the most ridiculous global warming scenario can't begin to compete with a scenario where an ice sheet covers almost all of North America and global precipitation is decreased by 90%... something that has happened in the past, as regular as clockwork.
The biggest problem on the face of that theory is it says that the interglacial periods end because of a megastorm caused by certain conditions including "that the Earth be at or near perihelion...at the time of the northern winter solstice." Aside from the question of how that condition is going cause a megastorm, that condition happens on a 23,000 year cycle. A 23,000 year cycle is indeed contained in the ebbs and flows of glaciation, however, the interglacial periods (and the ends of interglacial periods and return of the glacial periods) happen on a 100,000 year cycle. The 100,000 year cycle corresponds to the change in the eccentricity in the earth's orbit... the one orbital parameter that should have the least impact upon the climate according to our (obviously flawed) understanding.
Re:RIP (Score:5, Insightful)
..., such as glaciers melting (and yes, they truly are, worldwide, where I live here in Switzerland, but also in Alaska for example). I understand that there should be healthy scepticism at any scientific claim, but the climate is almost certainly changing, enough so that I can personally see it.
The climate is definitly changing.
As it always has been. Sometimes slower, sometimes faster. But in no way that should be an excuse to keep on polluting the planet.
Re:Dry? (Score:3, Insightful)
Looking up at night and recording what you see isn't exactly a new phenomenon, or limited to our technology.
People around the world have been doing both for a few millennia at least.
And, while I lack any peer-reviewed data source here, I would posit that those in an agricultural environment will actually be paying *more* attention to what clouds are doing than those in an industrial area.