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This model shows what could one day be the world's biggest telescope. Its main mirror will measure 42 meters in diameter. It's been designed for the European Southern Observatory. The Extremely Large Telescope - or E.L.T as this kind of telescope is called -  will give astronomers an unprecedented look at space.

Matthias Steinmetz of the Astrophysical Institute Potsdam explains: "The larger it is, the more light it collects and the deeper it can see into the universe."

Bildunterschrift: European Extremely Large Telescope - unprecedented look at space

Flexible like gum

The ground-based telescope will detect the visible and infra-red light that's penetrated the atmosphere. To correct the distortions of the incoming light, Markus Kissler-Patig and his team are applying a sophisticated technique known as Adaptive Optics. He developed it at the European Southern Observatory. 

“By the time they reach the telescope, the smooth images coming from space have been distorted by the earth's atmosphere,“ says Markus Kissler-Patig. “So we need to correct these distorted pictures . What we do is build a mirror into the telescope - not a smooth one, but one that we can deform. We deform it a hundred times a second - after calculating exactly how the deformations have to look to smooth out the distorted images. It passes on the smoothed-out images to the instruments. It can turn a blob into a high-definition image."

Making the mirror is a huge challenge. So far it's possible to make single mirrors with a diameter of eight meters. But 42 meters? Impossible.

So the Extremely Large Telescope's main mirror will be made up of 984 smaller ones fitted together. Each part can be adjusted separately.

The makers also have to secure the telescope against earthquakes, storms and other extreme conditions.

Stormy location

Bildunterschrift: Großansicht des Bildes mit der Bildunterschrift:  Quake-proof and storm-proof: A possible location is the Chajnantor plateau in Chile

A possible site for the giant telescope is the high, dry Chajnantor plateau in Chile. The ESO has already started to build another telescope there. Called ALMA, it will have an array of antennas that will scan the universe in the radio-frequency part of the spectrum. Together, ALMA and the ELT should provide astronomers with fabulous new insights.

Markus Kissler-Patig: “One of the main questions we'll be asking is:  Are we alone in the universe? Is there life outside our solar system, outside our planet? We'll be looking for answers to those questions."

And the Europeans are prepared to pay for it. The costs of designing, constructing and operating the 42-meter telescope will exceed 800 million euros. For that they'll get an instrument beyond the wildest dreams of Galileo - who first looked through a telescope at the night sky 400 years ago.