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Astrocomb breakthrough by physicists in Cambridge and Edinburgh will aid search for Earth-like planets

Undiscovered planets may soon be revealed, thanks to a technological breakthrough.

Physicists at the University of Cambridge and Heriot-Watt University in Edinburgh have developed a form of astrocomb – a laser system that allows astronomers to observe tiny changes in the colour of starlight, revealing hidden planets in the process.

The breakthrough will help the search for Earth-like planets
The breakthrough will help the search for Earth-like planets

It could also improve understanding of how the universe naturally expands.

Astrocombs were previously limited mainly to the green-red part of the colour spectrum.

However, the breakthrough will allow scientists to utilise the ultraviolet to blue-green part of the spectrum.

Dr Samantha Thompson, an astrophysics senior research associate at the Battcock Centre for Experimental Astrophysics, part of the Cavendish Laboratory at Cambridge, said: “This is a really exciting development that will enable us to study smaller planets on longer orbits than ever before – with the aim of discovering the first ‘Earth-like’ planet orbiting around a nearby sun-like star.”

Prof Derryck Reid, of Heriot-Watt, said: “Astrocombs allow astronomers to make extremely sensitive wavelength measurements of the spectrum of light, potentially tens to hundreds of times better than conventional technology.

“Much like the millimetre scale on a ruler lets us measure distances precisely, an astrocomb gives astronomers a precision scale for measuring wavelength.

“Until now, astrocombs operated mainly in the green-to-red part of the spectrum of light, but the shorter-wavelength ultraviolet to blue-green region is rich in the atomic absorption features of interest to astronomers.

“Our new approach for the first time provides a continuous sequence of optical markers from the ultraviolet to the blue-green that serve as a precision wavelength scale in this part of the spectrum.”

Prof Reid’s team is developing the technology for the Extremely Large Telescope, currently under construction in Chile.

They also work with astronomers in Cambridge, Uppsala and Capetown on astrocombs for telescopes in the Canary Islands and South Africa.

Prof Reid said astrocombs operate similarly to distortion on an electric guitar.

He said: “A nice analogy is in rock music, where audio distortion is heard when the signal from an electric guitar is high, but not when it is lower.

“That distortion is simply new audio frequencies being created in the guitar amplifier: our devices do the same thing, but for light.

“Importantly, we’ve achieved a wide and continuous spectrum of ultraviolet to blue-green colours using a laser with remarkably low power, and of the same kind already in use in some astronomical telescopes.”

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