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THE sun and the moon came togetheryet again on October 24, 1995, after Ilong years, in a dazzling display of celetial reunion. Earthlings watched -awestruck and spellbound. But whichthe sociocultural significance of thevent was well marked, scientists keltheir fingers crossed over any new scence that might emerge out of this cele!tial rendezvous.
Innumerable watchers, including 3Japanese and 26 American scientistarrayed themselves at differentpoints along the 40-krn wide pathof totality - region in which thesun is completely masked by themoon's shadow. "Essentially,"explained Ramnath Cowsik of theBangalore-based Indian Instituteof Astrophysic and the manbehind the entire scientificendeavour, 'the experiments con-ducted during the eclipse had twoobjectives. One - to demystify thetew remaining mysteries of the sun, and two - to seek a betterunderstanding of the complexrelationship between the sun anddw earth."
The corona - the fiery haloenveloping the sun but visible only durag total solar eclipse - was the cynosure of scientific eyes. That it is a million4kgrees hotter than the sun itself hasbdfled scientists for long. One explananon is that magnetic fields intrudingveto the corona get warped releasingpmerous amounts of heat. So, scientistswwd to look for optical signatures ofmrtain elements like iron and calcium*a signify very high temperatures. Thence of these elements can then beprese elated to the magnetic fields theory.
Another solar oddity that attractedtion was the dust rings, supposedlynts of dead comets swept towards'th by the sun. The rings,predicted long ago, had remainedelusive so far.
This was also the first time that adetailed study of atmospheric solar'winds' was conducted. Solar winds aremagnetic fields that emanate from thesun and cause the famous phenomenonof Northern Lights. Sometimes theycome so close to the earth's surface thatthey disrupt the power supply networks.
Redefining the sun's radius is a regular during a total solar eclipse. Thistime scientists from NASA and the Punebased Inter University Centre forAstronomy and Astrophysics (IUCAA),set themselves up near Agra to measurethe solar diameter and its long-termvariations. The results are already out:the sun's new radius is 650 kin longerthan hitherto measured - 6,96,000 kindisclosed N C Rana of IUCAA.
- At Diamond Harbour, Calcutta, sci-entists from the Saha Institute ofNuclear Physics set up experiments todetect electrical charge and mass of cosmic rays. Other than being just protonsand neutrons, cosmic rays are heavierparticles which disintegrate while reachthe earth. A total solar eclipse is ariginique opportunity to detect cosmic rayarticles because the sun is masked temorarily.
Delhi University and the National'hysical Laboratory (NPL) scientistsought gravity waves in the cosmic clut2r showered on the earth. Postulatedut never identified, these supposedlylay a major role in the circulation of-iiddle and upper atmosphere.
Another NPL team studied changes-1 radio waves intensity received from11 India Radio and other sources atNeem Ka Th4na and DiamondHarbour. The observations, thescientists say, will help plan India'stransmission networks better.They also studied the variation inthe intensity of visible, infra-redand near infra-red rays. Accordingto them, the purpose of the experment was to gauge the aerosolcontent in the atmosphere whichhas a cooling effect on the latter.
The star attraction during theeclipse was an MIG aircraft chasingthe moon's shadow over the entireline of totality in India, flying at analtitude of 22 km. It photographedthe moving lunar shadow as well as thecorona. This exercise was carried out forthe first time in India.
The results of all these endeavours,however, would only show up aftersome months.
Despite academic efforts, many scientists were sceptical of any remarkablefinding coming out of this event Remarked R K Kochhar of the iiA"We've come a long way from the totalsolar eclipse of May 29, 1919, whenEinstein's General Theory of Relativitywas experimentally proven. The totalsolar eclipse is a horse that has beenflogged ad nauseam." If nothing, asCowsik remarked, the academic exercisewill surely yield at least 20 to 30 Ph.Dtheses.