சனி, ஆகஸ்ட் 07, 2010

Pieces of microscopic matter tell galactic tale of early Earth

One is a speck of interstellar stardust -- a world scientific first -- collected by a NASA space probe and identified, via the Internet, by a career carpenter from Midland, Ont., who wanted to make good use of his retirement following a stroke.
The other is a minuscule piece of charcoal found among geological specimens chiselled out of Quebec's Gaspe Peninsula, a telltale sign of terrestrial life -- and one of the planet's first wildfires -- from about 400 million years ago.
The microscopic objects with notable Canadian connections are just two of the latest nano-scale discoveries helping scientists shed light on the history of the universe and early Earth.
And in the case of Ontario "citizen scientist" Bruce Hudson's stunning find -- revealed earlier this year at the Lunar and Planetary Science Conference in Houston and highlighted this week by the New York Times -- the story encompasses nothing less than the birth of galaxies, the death of stars and the beginning of time.
As for the Quebec find -- a key piece of evidence for a study published this week by British and U.S. researchers in the journal Nature Geoscience -- it has helped experts reconstruct how oxygen levels in the Earth's atmosphere have risen and fallen over the ages in tandem with the evolution of plants and animals.
The interstellar dust particle spotted by Hudson appears to be an even more significant scientific speck, one of the most high-profile findings following a seven-year, 4.8-billionkilometre interplanetary voyage by NASA's Stardust spacecraft.
Before the end of its mission in 2006, the probe had used a kind of flypaper receptacle to catch millions of pieces of cosmic dust.
Much of the collected material came from comets chased by the probe. But scientists suspected some of the particles might be bits of interstellar dust -- free-floating leftovers from the Big Bang origins of the universe or subsequent supernova.
An army of more than 20,000 "citizen scientists" was invited to pore over millions of magnified images via a NASA-sponsored website.
And earlier this year, scientists revealed that Hudson -- a Canadian astrology buff who sometimes spent more than 10 hours a day searching his computer screen for signs of interstellar dust -- had identified what appears to be the first piece of the stuff known to science.
The object reported by Hudson has since been classified as two separate particles, which he was entitled to name. They've been dubbed Orion and Sirius.


கருத்துகள் இல்லை:

கருத்துரையிடுக