Megacryometeor
Template:Short description Template:Weather A megacryometeor is a very large chunk of ice which, despite sharing many textural, hydro-chemical, and isotopic features found in large hailstones, is formed under unusual atmospheric conditions which clearly differ from those of the cumulonimbus cloud scenario (i.e. clear-sky conditions). They are sometimes called huge hailstones, but do not need to form under thunderstorm conditions unlike hailstorms. Jesús Martínez-Frías, a planetary geologist and astrobiologist at Institute of Geosciences (Template:Langx, IGEO) in the Spanish National Research Council (Template:Langx, CSIC)<ref name="Web CSIC, 2017">Template:Cite web</ref> in Madrid, pioneered research into megacryometeors.
Mass and size
More than 50 megacryometeors have been recorded since the year 2000. They vary in mass between Template:Convert to several tens of kilograms. One in Brazil weighed in at more than Template:Convert.<ref>Gelo caindo do céu assusta moradores Template:Webarchive Template:In lang.</ref> Chunks about Template:Convert in size also fell in Scotland on 13 August 1849.<ref>Template:Cite book</ref>
Formation
The process that creates megacryometeors is not completely understood yet, mainly with respect to the atmospheric dynamics necessary to produce them. They may have a similar mechanism of formation that leads to the production of hailstones.<ref name="damn">The Peculiar Phenomenon of Megacryometeors by Alan Bellows.</ref> Scientific studies show that their composition matches normal tropospheric rainwater for the areas in which they fall. In addition, megacryometeors also display textural variations of the ice surface and hydro-chemical and isotopic heterogeneity in its composition, which gives potential evidence to a complex formation process in the lower atmosphere.<ref name=r1>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> It is known that they do not form from airplane toilet leakage because the large chunks of ice that occasionally do fall from airliners are distinctly blue due to the disinfectant used by them (hence their common name of "blue ice").
Some have speculated that these ice chunks must have fallen from aircraft fuselages<ref name="damn"/> after plain water ice accumulating on those aircraft through normal atmospheric conditions has simply broken loose. However, similar events also occurred prior to the invention of aircraft.<ref>Template:Cite book</ref><ref>Riesgos Naturales, by Olcina Santos, J. and Ayala-Carcedo, J.</ref> Studies indicate that the metrological fluctuations in tropopause, associated with hydration of the lower stratosphere and stratospheric cooling, can be related to their formation.<ref name=r1/> A detailed micro-Raman spectroscopic study made it possible to place the formation of the megacryometeors within a particular range of temperatures: Template:Convert.<ref>Template:Cite journal</ref> They are sometimes confused with meteors because they can leave small impact craters, though they form in the atmosphere and not from outer space.
References
External links
- Megacryometeors: Resource Site
- News Report: Ice Chunk Hits Oakland, CA, USA
- The Peculiar Phenomenon of Megacryometeors
- Getting to the truth of falling ice chunks, Chemical Science, Katherine Davies, 2008
- What Causes Megacryometeors?
- The problem of Ice Meteorites, Martin Beech
- Top 100 Stories of 2008 #73: Giant Ice Meteors Fall From Clear Skies, Karen Wright
- HALS (blog with cases)