Monday 21 April 2014

M.Biot météoritricien extraordinaire

It's 14 months since the most spectacular extra-terrestrial event of this present century appeared in the sky over Челябинск in Central Russia.  It was a 10,000 ton meteorite that entered the atmosphere at 60,000 km/h getting hotter as it shoved the increasingly dense air out of its way.  Shortly after 0900hrs local time it exploded with a force estimated at 500 kilotons of TNT, blowing out windows, damaging roofs and injuring more than 1000 people, some seriously.  The flash was brighter than the sun and visible from more than 100 km away.  Thanks to the Russian love-affair with dash-cams on their cars, the event was captured on film from several angles. There has been a brisk trade in fragments of The True Rock which were relatively easily located because their final trajectory was visible as holes in a landscape covered in snow. The going rate for teeny bits seems to be about $30/g.  Several large chunks whanged through the ice on Lake Chebarkul 70km West of Chelyabinsk and somebody must have triangulated the holes from the shore because last summer there was an ongoing raree show as divers went under to retrieve the pieces.  The largest was fished out in October and promptly broke into three pieces when it crushed the wholly inadequate scale - the bits totalled 570kg.  I doubt if the finders will get a  pro rata $17million for it but it must be worth more than our humble farm.

The audit trail is so clear that nobody doubts that Chelyabinsk LL5 came from out there.  It was different 200 years ago when science was still laboring under the the intellectual burden that the celestial spheres were making music for the gods and had no physical connexion with earthbound material.  In 1794, Ernst Chladni, one of the great scientific polymaths of that revolutionary era published a weighty book called "Über den Ursprung der von Pallas gefundenen und anderer ihr ähnlicher Eisenmassen und über einige damit in Verbindung stehende Naturerscheinungen".  Which Blobotrans renders: On the origin of the Pallas object and similar Iron-rich masses and some related phenomena.  Chladni's conclusion was that the Pallas rock must be from outer space.  The following year Howard and de Bournon analysed another meteorite and concluded, from a careful chemical  analysis, that it was most likely not from this earth.  But these men were merely crying in the wind because everybody knew that meteorites were ejected from volcanoes. In the same way that everybody knew that the hen cuckoo disposed of the eggs before laying her own in another bird's nest.

In April 1803 another meteorite shattered over the town of L'Aigle in Normandy.  Another scientific polymath Jean-Baptiste Biot was dispatched by the French Academy of Science to investigate.  He was just 29 having been born on 21st April 1774 and had another 50 years of diverse scientific research ahead of him.  His appearance very shortly after the event, his analysis of the stones, his interviews of the eye-witnesses, his comparison of the data with the literature on other meteoric fragments and a clearly written report all conspired to vindicate Chladni's radical idea.  If you're French you're likely to know Biot as the Father of Meteorology.  If you're Polish, German, Slovak or Magyar you're more likely to give that title to Chladni - all of those nations lay some claim to him as one of their sons. It's similar to the tug-of-fame that Gregor Mendel has experienced since he lived and died in roughly the same area of central Europe.  Let's stuff all that nationalism and call Chladni a Citizen of Science.

But as it's Biot's bday, let's agree to cheer him to the heavens.

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