* Astronomy

A meteorite that fell in Piplia Kalan, a western Rajasthan village, has changed the way scientists think about the birth of the solar system.
Piplia Kalan is a small, nondescript village in Pali district in western Rajasthan. People outside the district would not even have heard its name. Yet, it is a name familiar to planetary scientists and astronomers, and a casual search on Google for 'Piplia Kalan' will fetch you many entries. It does not owe its fame to any natural calamity or scandal but to a piece of a meteorite.
A shooting star fell on an uncultivated farm on the outskirts of Piplia Kalan on June 20, 1996, around 8-30 in the evening. Most villagers were probably enjoying the summer evening outside their homes, and the meteor that streaked brightly across the sky did not escape their notice.
The 'Piplia Kalan' meteorite was rather small by the standards of famous meteorites. I t did not even weigh 50 kg - so it was far from being dangerous like the one that is believed to have brought about the extinction of the dinosaurs, or even the one that in 1908 exploded over Siberia and destroyed a forest there. The Piplia Kalan meteorite was tiny in comparison. Yet, the surviving fragment of this meteorite contained an extraordinary piece of information, which has changed the way scientists think about the birth of the solar system.

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Latitude= 26.03485 Longitude= 73.94151

Elaborate tests conducted on a meteorite fragment found after it had crashed in Rajasthan recently has revealed it to be a very rare iron meteorite exuding significant radioactivity. A variety of tests were conducted by scientists of the Phyical Research Laboratory and Basic Sciences Research Institute on the meteorite which fell at Bhuka village in Barmer district of Rajasthan, India, on June 25, this year.

"The results of our study indicate that it is a rare iron meteorite having a significant radioactive content of 54Mn (manganese) and 57Co (cobalt). It seems to have originated from the asteriodal belt between Mars and Jupiter and might have been 100 times bigger than the its present weight of about 2.5 kg" - Mr Narendra Bhandari of the BSRI, and president of International Lunar Exploration Working Group.

Tests were still to be conducted to arrive at the estimated time the meteorite to travel from the belt to Earth.
The meteorite, which fell in the farm of Mubeen Sindhi with a loud noise, made a crater of about half-a-metre and is actually an alloy of iron and nickel.
The iron meteorite is the rarest of the three kinds of meteors, the other two being stony meteors and stony iron meteors.

"It is the first iron meteorite to fall in Rajasthan among the seven falls in the past 15 years. Moreover, for the radioactive isotopes of cobalt and manganese to be found together in a single meteorite is very rare and it is perhaps the first time they have been found on earth" - Mr Narendra Bhandari.

He was able to detect the radioactivity because the meteorite was sent to him immediately after it fell.
"About 80 per cent of most meteors entering the Earths atmosphere burn out. What makes iron meteorite rare on Earth is because unlike stony meteors they have a tendency to completely burn out" - Mr Narendra Bhandari.

The meteorite has a thick black crust with a golden or brownish tinge. The crust also has well developed regmaglypts (thumb marks formed when the meteorite enters Earths atmosphere) typical of meteorites.

"The tests conducted on a piece of the meteorite sent to PRL (a large chunk was also sent to the Geological Survey of India), also found it to be made of pure iron which is very different from the kind of iron usually found on Earth which normally exists as an oxide".

The iron and nickel alloy which the meteorite is made of, was formed at very high temperatures, in reducing atmosphere devoid of oxygen or water at least four-and-a-half billion years ago. The meteorite also has a special crystalline structure which is indicative of the slow cooling process it witnessed.

"This is the seventh observed fall in the past 15 years in Rajasthan the other six meteorite falls being at Didwana (1991), Lohawat (1994), Devri Khera (1994), Piplia Kalan (1996), Itawa Bhopji (2000) and Bhawad (2002)."

Since only about 126 falls have been observed all over India in the past two centuries, this frequency of falls (one every two years) in such a small area of Rajasthan is very unusual. In comparison, no more than 10 falls have been reported from the rest of India in the past 15 years, Mr Bhandari observed.

Certain questions as to whether this observation is just a regional or temporal statistical fluctuation or whether the Earth is going through an unusually dense swarm of interplanetary bodies continues to remain unanswered, Mr Bhandari added.

(Adapted) source