Paper: The Toronto Star Location: Toronto, Ontario, Canada Date: June 1, 2000
Meteorite find excites scientists By Peter Calamai Yukon Fragments offer `best chance ever' to study birth of our solar system. 'This is our best chance ever to see what organic chemicals were present when the sun and planets were formed 4.5 billion years ago. It was likely a small asteroid that once . . . had water.' Michael Zolensky NASA cosmic mineralogist SCIENCE REPORTER OTTAWA - Traces of the chemical building blocks of the solar system - and of the human race itself - may well be preserved inside hundreds of pieces of a rare meteorite recovered recently from the ice surface of a Yukon lake. The Tagish Lake meteorite is the largest meteorite fall in Canada and the pieces are the least contaminated of any meteorite ever recovered anywhere in the world. ``This is our best chance ever to see what organic chemicals were present when the sun and planets were formed 4.5 billion years ago, '' said Michael Zolensky, a cosmic mineralogist with the National Aeronautics and Space Administration. While the meteorite's outer layers reached white hot temperature as the fireball flashed through the atmosphere on Jan. 18, the inside would have remained cold, preserving any delicate organic molecules trapped there. Some of those molecules were captured from the swirling gas cloud that later became our solar system, scientists said. Zolensky joined researchers from the University of Calgary and the University of Western Ontario at a news conference in Calgary yesterday to explain the significance of the find. Initial lab tests of tiny samples reveal the meteorite contains water and is of a type called a carbonaceous chondrite, with 50 times as much carbon as the much more common stony meteorites. The previous carbonaceous chondrite was recovered 31 years ago. ``This is the scientific equivalent of a NASA sample return mission to an asteroid using a satellite that would have cost $100 million, '' said Peter Brown, a meteor researcher at the University of Western Ontario. The meteorite fragments look like burnt charcoal briquettes and easily break apart because of the high carbon content. Satellite photos that captured the path of the Yukon fireball plus eyewitness accounts allowed researchers to calculate that the meteorite came from an asteroid once in orbit between Mars and Jupiter. ``It was likely a small asteroid that once reached at least room temperature, had water and a higher organic content than the earth, '' said NASA's Zolensky. Forty grams of recovered meteorite will be parcelled out to researchers around the world and scientific probing of the rocks could last for years. But there is more of the meteorite to go around because of a race against time that swelled the find from an initial one kilogram of rock to at least six kilograms and maybe as much as 10. Meteorite searchers rushed to recover the fragments before spring weather melted the ice covering Tagish Lake between Atlin in northern B.C. and Carcross in the Yukon. On a first visit in February they tried using RCMP sniffer dogs, but the animals had been trained for different smells. Then the searchers looked for spots where wolves had urinated because past meteorite fragments attracted such behaviour. In the end the team of a half-dozen searchers had to come back April 20 when most of the snow covering the lake was gone. By May 8, when the ice on Tagish Lake was declared unsafe, searchers had noted about 500 spots where meteorites had bored into the ice and retrieved roughly 200 fragments. Most meteorites that crash into Earth are contaminated by landing in soil or quickly lose the rarer organic chemicals as gases in the warmer conditions here. But the Tagish Lake meteorite avoided these dangers because it landed on ice that kept it frozen and largely pristine. ``Of all the times I dreamed of finding meteorites, I could never have dreamed of finding anything like this,'' said an ecstatic Alan Hildebrand, a planetary scientist at the University of Calgary. ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
