Astronomy breakthrough could help discover 'first Earth-like planet'

A Scottish university has developed a tool that could help discover the “first Earth-like planet", scientists have claimed.

Physicists from Heriot-Watt University and the University of Cambridge have developed a laser system that they say could help identify the “telltale signs” of hidden planets. 

The new tool will offer a more accurate study of the spectrum of light from nearby stars, allowing for sensitive measurements of how the universe is expanding. 

Astrophysics researcher from the University of Cambridge, Dr Samantha Thompson, said: “When astronomers hunt for exoplanets with the Radial Velocity technique, they study the light from stars.

“Planets orbiting these stars cause the star to move, bringing about tiny changes in the colour of the starlight – if we can accurately measure those, we can discover and characterise new planets.”

The new laser system, known as astrocomb, allows for “extremely sensitive wavelength measurements” of the light spectrum, potentially “tens of hundreds of times better” than current technology, Professor Derryck Reid from Heriot-Watt University said.

It is the first-ever tool capable of "continuous coverage" from the ultraviolet to the blue-green spectrum, which “is rich in the atomic absorption features of interest to astronomers”, he added.

“We achieved this by using special devices that exhibit so-called ‘nonlinear optical effects’, which can dramatically change the colour of a laser beam if its power is sufficiently high,” he said.

“A nice analogy is in rock music, where audio distortion (‘nonlinearity’) 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.”

The technology will be integrated into the Extremely Large Telescope, currently under construction in Chile.

The team is also working with astronomers in Cambridge, Uppsala and Capetown on astrocombs for telescopes in the Canary Islands and South Africa.