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Revealed: The coldest, calmest place on earth

September 01, 2009 16:39 IST

In a study to assess the many factors that affect astronomy, a joint US-Australian research team has found the ideal location for an observatory -- known simply as "Ridge A".

The untouched stretch of Antarctic terrain has been dubbed the coldest, calmest and driest place on Earth. It is expected to yield images of the heavens three times sharper than any ever taken from the ground.

The team combined data from satellites, ground stations and climate models to assess factors that affect astronomy -cloud cover, temperature, sky-brightness, water vapour, wind speeds and atmospheric turbulence.

The researchers pinpointed a site -- known simply as Ridge A -- that is 4,053m high up on the Antarctic Plateau. It is not only particularly remote, but extremely cold and dry.

The study revealed that Ridge A has an average winter temperature of minus 70 degree Celsius and that the water content of the entire atmosphere there is sometimes less than the thickness of a human hair.

It is also extremely calm, which means that there is very little of the atmospheric turbulence elsewhere that makes stars appear to twinkle: 'It's so calm that there's almost no wind or weather there at all,' says Dr Will Saunders, of the Anglo-Australian Observatory and visiting professor to UNSW, who led the study.

'The astronomical images taken at Ridge A should be at least three times sharper than at the best sites currently used by astronomers,' says Dr Saunders.

'Because the sky there is so much darker and drier, it means that a modestly-sized telescope there would be as powerful as the largest telescopes anywhere else on earth,' the expert added.

They found that the best place in almost all respects was not the highest point on the Plateau -- called Dome A 00 but 150km away along a flat ridge.

'Ridge A looks to be significantly better than elsewhere on the Antarctic plateau and far superior to the best existing observatories on high mountain tops in Hawaii and Chile,' says Dr Saunders.

The finding was published on Tuesday in the Publications of the Astronomical Society.

(Image only for representational purpose)

Image: David Vaughan, a glaciologist with the British Antarctic Survey, installs a pole as part of a satellite monitoring system into the Wilkins Ice Shelf off the Antarctic Peninsula

Photograph: Alister Doyle/Reuters