Brussels, 14 Jul 2005
Scientists within the EU funded OPTICON project have formally argued the case for the construction of the European Extremely Large Telescope (ELT) - an optical telescope the size of a sports field that could watch the seasons change on a planet orbiting a star on the other side of the galaxy.
The case was made at a meeting of scientists involved in the project held in Dwingeloo in the Netherlands. OPTICON is funded with over 19 million euro under the Infrastructures priority of the Sixth Framework Programme (FP6).
According to the plans outlined at the meeting, the telescope could measure 50 or even 100 metres across and cost well over 1 billion euro to build. To put that into perspective, the largest telescope so far made measures just 10 meters across.
Gerry Gilmore from the University of Cambridge said: 'We want to be able to see planets around other stars. The interesting ones are the small rocky planets. The fundamentally new thing is to find planets that might have life on them and watch the seasons changing and the polar caps coming and going.'
Constructing the ELT presents a number of challenges, however. For example, the Earth's atmosphere causes light from the stars to refract, creating a 'twinkling' effect for the brightest stars and obscuring the fainter objects altogether. Scientists must perfect a system of 'adaptive optics' to cancel out this effect, and one solution may involve laser beams taking up to a thousand readings of the atmosphere per second to feed computer operated pistons that continuously alter the mirror's surface to compensate.
It is still not entirely clear what all of the uses of such a large telescope would be, but its proponents argue that this is no reason not to build it. 'You might say, 'This is ridiculous. Why are you building a telescope when you don't know what you are going to do with it?' But everything we are doing with our telescopes today wasn't discovered when those telescopes were built,' concludes Professor Gilmore.
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