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The Cosmos: A Beginner's Guide - Seeing the universe

Updated Friday 6th July 2007

Most of what we know about the universe, from its age to its size to how it began in a Big Bang, has been found out through telescopes. But how far out into space and back into time is it possible to see?

Dr Maggie Aderin-Pocock among mountains in Chile Copyrighted image Icon Copyright: The Open University

In this episode Adam Hart-Davis travels to the Atacama Desert in Chile to visit the VLT - the Very Large Telescope. Perched on top of a flattened mountain some 2600 metres above sea level, the VLT is the best place on Earth from which to see the universe. Head of Science, Bruno Leibundgut, explains how this awesome telescope is helping astronomers see further than ever before, enabling them to tackle some of the “big” questions in astronomy.

Before the VLT, our most powerful telescopes were the ones we sent into space. The Hubble Space Telescope is perhaps the most famous. Launched in 1990, it has peered into the Cosmos for over a decade, capturing mind-blowing images across the universe. It has its accomplices, though. We sent Maggie Aderin to Hubble’s European Headquarters, to meet Lars Lindberg-Christensen and a team of cosmic artists who work with Hubble’s scientific data to create the beautiful images we know and love.

Meanwhile, back in Chile, Adam finds out how a new system of bendy mirrors called “adaptive optics” is helping the VLT see as clearly as Hubble. This sophisticated optical system works by eliminating the distortion caused by the Earth’s atmosphere and looks set to usher in a new generation of even larger Extremely Large Telescopes!

Today’s astronomers aren’t just interested in collecting as much light as possible with giant mirrors, though; they are also interested in squeezing as much information as they can out of the light they collect. We follow Maggie Aderin to the Gemini Telescope, 400km south of the VLT, to check up on an instrument she built there and learn how it’s helping astronomers work out not only how far away stars and planets are but what they consist of as well.

As night falls at the VLT, Adam joins Bruno in the control room. Tonight he is looking at stars exploding at the very edge of the universe. In their violent end it is hoped these distant stars may shed light on one of the toughest questions facing astronomers today - how fast is the universe expanding? The suspicion is it’s expanding faster and faster and Bruno’s work may provide the evidence.

Distant stars aren’t just a long way away, though; they are a long time ago, too. But how far back in time can we look? Behind the beach in glamorous Cannes in the South of France a satellite is being built which will detect the very first light in the universe. We take a peek at this new satellite, Planck, and Francois Bouchet explains how it will take the most detailed picture ever of our infant universe .

But what about the stuff in the universe that doesn’t shine? From black holes to dark matter, there’s a lot we just can’t see. That doesn’t mean we can’t detect it, though. Maggie Aderin travels to the European Gravitational Observatory in Pisa to check out an entirely new way of seeing the universe. It isn’t operational just yet but the Virgo experiment could revolutionise astronomy and change the way we view the universe forever.

First broadcast: Tuesday 7 Aug 2007 on BBC TWO


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