Comet dust discovered first time on Earth's surface

WASHINGTON: Researchers have discovered comet dust preserved in Antarctic ice and snow, the first time such particles have been found on Earth's surface.

Until recently, the only way scientists could collect comet dust without going to space has been by flying research planes high in the stratosphere. Several hours of flying time typically yield one particle of dust.

Working with such small samples significantly limits the kinds of tests and analysis scientists can perform on the material, said study co-author John Bradley, an astromaterials scientist at the Hawaii Institute of Geophysics and Planetology of the University of Hawaii, Manoa.

The researchers have found a bigger haul of the particles in Antarctica, 'Science' reported.

"Two to four more orders of magnitude mass of material is potentially collectible this way. I think it could precipitate a paradigm shift in the way these kinds of materials are collected," Bradley said.

In 2010, a team of French scientists reported that they had found dense, unusually carbon-rich comet particles in the Antarctic snow, but this is the first time more typical comet dust has been found and its identity confirmed, researchers said.

The study researchers collected snow and ice from two different sites in Antarctica over several years, starting in 2000.

By melting the ice and filtering the water, they collected more than 3,000 micrometeorites, tiny particles from space that were 10 microns in diameter or larger.

Analysing the micrometeorites one by one under a stereomicroscope over a period of 5 years yielded more than 40 particles with the characteristics of comet dust.

A closer analysis found they were indistinguishable from comet dust collected in the stratosphere, and they also matched samples collected from the coma of a comet by NASA's Stardust mission in 2006.