Giant laser creates an artificial star to clear the sky

Flora Graham, editor, newscientist.com

(Image: ESO)

It looks like a Stormtrooper's snapshot of the Death Star's superlaser in action, but this is actually a photo of a new laser that's just completed testing at the Very Large Telescope in Chile.

The laser shoots 90 kilometres into the atmosphere, where it interacts with the 10-kilometre-thick layer of sodium atoms left around our planet by meteoroid impacts. The laser makes the sodium fluoresce, producing a bright point of light that acts as an artificial star.

Astronomers use this pinpoint as a reference to monitor atmospheric turbulence in the telescope's line of sight. Deformable mirrors in the telescope shift in response to these measurements, compensating for the atmosphere's distortions and creating much sharper images of the heavenly bodies beyond.

Researchers say that the new laser is more flexible and reliable than the previous one, which is being retired after six years of service.

"When we started developing these lasers, everyone said our goal was nearly impossible - even many of the other experts," says Domenico Bonaccini Calia of the European Southern Observatory (ESO), which runs the telescope.

Calia calls the new laser a "breakthrough" and hopes to share the technology "with the wider community". We hope that doesn't include moon-sized battle stations.

Source: http://feeds.newscientist.com/c/749/f/10897/s/28fbc12a/l/0L0Snewscientist0N0Cblogs0Cshortsharpscience0C20A130C0A20Cgiant0Elaser0Bhtml0Dcmpid0FRSS0QNSNS0Q20A120EGLOBAL0Qonline0Enews/story01.htm

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