Thursday, 3 April 2008

Another great science story

From here;
The comb helps identify the tiny changes in the wavelength of the light from the parent star, which goes imperceptibly bluer when moving towards us and redder when moving away.

The effect of gas giant Jupiter on the Sun, which is one thousand times more massive, cause wobbles of around plus or minus 13 metres per second.

The comb uses a laser to provide a series of highly accurate reference frequencies, like the teeth of a comb, that can be used to measure the way the light waves are stretched and squeezed as a result of movements as small as a metre per second and, in theory, this sensitivity could be improved another 100 fold.

This is five times more than the sensitivity needed to spot Earth from an alien star system. In 2009 or 2010 the team hopes to achieve this sensitivity in an instrument under construction for the William Herschel telescope on the Canary Islands.

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