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Noctilucent Clouds Likely Caused By Shuttle Launches
icebike writes "In our recent discussion of the phenomenon of noctilucent clouds, there was some suggestions that these might be the product of global warming due to moisture being lofted high into the atmosphere. It now appears that these clouds are simply the product of Shuttle launches. In a story about the Tunguska blast, Science News says: 'Each launch of a space shuttle, which burns a combination of liquid hydrogen and liquid oxygen as fuel, pumps about 300 metric tons of water vapor into the atmosphere at altitudes between 100 and 115 kilometers. Soon after the January 16, 2003, launch of the shuttle Columbia, a liftoff that took place just after the height of summer in the Southern Hemisphere, noctilucent clouds appeared over Antarctica. Similarly, a widespread display of the night-shining clouds showed up over Alaska two days after the shuttle Endeavour blasted off on August 8, 2007. Previous studies show that in both instances those clouds included material from the shuttle plumes.' So, man-made after all?"
Those damn environmentalists were right!
The previous Slashdot thread included the tidbit that the first noctilucent clouds mentioned in recorded history were in 1887 (also noted here). So unless someone was using hydrogen-oxygen rocketry almost a full century before the first shuttle launch, it would seem that they are not purely anthropogenic.
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
Almost a full century before the first shuttle launch by humans! Finally we have proof for UFOs! :-)
The Tao of math: The numbers you can count are not the real numbers.
first noctilucent clouds mentioned in recorded history were in 1887
1887 was when the term was coined. It is impossible to say whether the phenomenon called "noctilucent clouds" in 1887 is the same phenomenon we see today. For example, Northern lights might qualify as "noctilucent" and may look cloudy to boot. It's important to distinguish the phenomenon from the terminology.
Just callin' it like I see it.
While I suppose the summary could be read that way, the actual article is a little more clear on the distinction. That some other events also cause noctilucent clouds, while true, does not invalidate the premise of the shuttle also causing them.
So mod parent down. Bitch about inaccuracies in the summary if you want, but don't pretend they serve as meaningful parts of the discussion.
Its also quite possible that the recent appearances of these clouds was caused by the shuttle launches dumping lots of water into the upper atmosphere, regardless of what has caused them in the past
Disregarding the 1887 thing, which is amply discussed above, what amazes me is this:
If these luminous clouds are caused by shuttle launches, why has it taken, 32 years and 128 launches for someone to discover this relation?
Or, has something else happened to the atmosphere not-so-long ago which, together with the launches, have been causing these clouds only recently?
"Good news, everyone!"
My theory, then, is that they were caused by the advent of photography, in much the same way Color was invented in the 50s.
And what happened around that time?
http://en.wikipedia.org/wiki/Krakatoa
You totally miss the point of the story. Its not the fuel mixture. Its the fact that large amounts of water vapor find their way to the upper atmosphere. Some by natural causes. Some by shuttle launches.
Sig Battery depleted. Reverting to safe mode.
From June, 2003: .... note the last sentence.
http://apod.nasa.gov/apod/ap030615.html
6 years.
Sometimes it takes main stream media a while to catch on.
Note that this APOD entry has further links to US Navy research on the topic.
Noctilucent clouds occur over a very small altitude range (about 82-84 km) Observations of the same cloud from different locations can be used to find the height by triangulation. ISTR that the 1887 observation did this and that it is therefore a genuine observation of NLC.
The question of whether there were no NLC before this date was a contentious one last time I asked. Some make the argument that NLC are very distinctive and that if they were there we would have records going back to the Viking era, as we do with the Aurora Borealis. Others, however, argue that NLC look sufficiently like other clouds and are sufficiently unremarkable to the casual observer that it is not surprising that there are no descriptions prior to 1887. (Remember that the idea that it is worth naming and describing clouds only really goes back to Luke Howard in the early 1800s.)