Read this blog post ONLY IF YOU DARE!!!!
I was just reading the latest edition of "Ripley's Believe It or Not! Enter If You Dare!" which was sent to me by the Ripley people to have a look at. Let me tell you right away that if you are a skeptic, you have to get a hold of this book and try to debunk every item in it. Well, not ever item, but many. Some of the strange things the book includes are not really all that strange, but are merely interesting, like certain geological formations and other phenomena. Others are simply physical abnormalities of humans or various non-human animals or plants, as per usual. For the most part, though, the items in this book are probably mostly for real, and a skeptical look will not debunk them. Thus, the challenge.
Let me demonstrate an example. One of the coolest things in the book is this photograph of an eruptionat Sarychev Peak, in the Kuril Islands:
The photograph was snapped by an astronaut flying by in the International Space Station. That alone would be an entry in "Ripley's Believe It or Not! Enter If You Dare!: Astronauts orbit earth in space station carrying an expensive digital camera, photograph volcanoes! Believe it or not!!!!" but, alas, we have become inured to such things.
Anyway, I thought I'd arbitrarily pick this photo and what the book said about it, run it down to check it's authenticity, and thus verify that Ripley's is both strange and skeptical. My conclusion: In regards to this particular strange thing, they basically got it right, but I quickly add, that what they said in the book is quite possibly wrong anyway, because science tends to march foreword and all. Let me splain.
The book says:
A camera on board the International Space Station witnessed the early stages of a volcanic eruption back on Earth that appeared to blow a gigantic hole int he clouds. The vast mushroom shape stretching above the Sarychev volcano on the Kuril Islands near Japan was thought to consist of brown volcanic ash and steam, which caused warm clouds to evaporate on either side of the eruption plume, leaving a clear hole in the cloud cover.
It turns out that this is one of three or four explanations that are currently on the table, but I quickly add that the multiplicity of explanations came after NASA posted the image and scientists started being all skeptical and stuff about it.
The following is from the original text posted at NASA's Earth Observatory web site:
... Sarychev Volcano... in an early stage of eruption on June 12, 2009 ...
... The main column is one of a series of plumes that rose above Matua Island on June 12. The plume appears to be a combination of brown ash and white steam. The vigorously rising plume gives the steam a bubble-like appearance.
[Alternatively], the smooth white cloud on top may be water condensation that resulted from rapid rising and cooling of the air mass above the ash column. This cloud, which meteorologists call a pileus cloud, is probably a transient feature: the eruption plume is starting to punch through. ...
(Do go read the original entry at the link provided, there is much more interesting commentary that happens to be tangential to the current blog post.)
Subsequently, NASA added this to the web page:
... Following the publication of this photograph, the atmospheric and volcanic features it captured generated debate among meteorologists, geoscientists, and volcanologists who viewed it [including] three possible explanations for the hole in the cloud deck above the volcano.
One explanation is that the hole in the clouds has nothing to do with the eruption at all. In places where islands are surrounded by oceans with cool surface temperatures, it is common for a sheet of clouds to form and drift with the low-level winds. When the cloud layer encounters an island, the moist air closer to the surface is forced upward. Because the air above the marine layer is dry, the clouds evaporate, leaving a hole in the cloud deck. ...
The other two possibilities that scientists have offered appeared in the original caption. One is that the shockwave from the eruption shoved up the overlying atmosphere and disturbed the cloud deck, either making a hole or widening an existing opening. The final possibility is that as the plume rises, air flows down around the sides like water flowing off the back of a surfacing dolphin. As air sinks, it tends to warm; clouds in the air evaporate.
What is interesting to me about this is that it may be a case of this phenomenon in which a hole gets punched in a cloud by, more typically, a turboprop airplane under just the right conditions, but in this case, a volcano. The test of this hypothesis ... that a threshold temperature effect has occurred ... might be the presence of precipitation in the area at ground level. Of course, with the volcano blowing up and all, it might be nearly impossible to ascertain if that happened.
I'm going to keep reading through Ripley's for more examples to be skeptical about. If you happen to have a copy of it, and know of some particular cases of interest, let the rest of us know!
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There is a short video of this, as well (oh, yes, NASA also has expensive digital video capabilities)- I think I saw it posted on Astronomy Photo of the Day. You can see the quite rapid expansion of the plume in the video, and as a result the suggestion that the hole is caused by anything other than the volcano seems quite ludicrous in my otherwise baseless opinion. My vote is for the shockwave hypothesis.
I was wondering about the speed at which this happened. Looking for video now...
http://www.youtube.com/watch?v=CnWOG8Eoq-8
Greg
I am not completely convinced that is a real-time video rather than a series of still shots or some such. The reason is that the volcanic clouds I have seen are very energetic affairs, not just going up but swirling and whirling within themselves.
The beginning of this gives a good idea:
http://www.youtube.com/watch?v=VaChWgbn18Y
Your posted video is strangely static within the cloud.
Sailor, I'm not convinced either, but there is a huge scale difference between the case cited above and your example.