Scientists capture the colours of creation

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The Independent Online
The different colours in this picture represent a breakthrough by British technology - and our clearest picture yet of the origins of the universe.

The range of colours here represent a total temperature difference of just 0.00001 degree Centigrade, in a part of the night sky which reveals distant echoes of the Big Bang. It was captured by CAT, a new radio-telescope designed by physicists at Cambridge University and situated near the city.

Scientists have long theorised that when the universe came into being , about 15 billion years ago, the galaxies began to form where matter and energy were clumped together. Such variations in density should show up as different temperatures in the sky, since the universe was enormously hot at its birth. Space is not completely cold: in fact it has an effective temperature of 2.7C above absolute zero, where activity stops entirely. But the variations are now tiny.

In 1992, the US space agency NASA offered definitive evidence of this, when its COBE satellite produced a picture of the entire sky, showing "ripples" in its temperature, confirming the theories and giving a broad glimpse of the after-effects of the Big Bang.

This picture shows those ripples in far greater detail than COBE did, from a time when the universe was only about 300,000 years old. CAT is 40 times more sensitive to temperature variations than COBE, yet cost a fraction as much - pounds 250,000, rather than $300m.

Rather than a satellite, the team used three radio antennae, each 70 centimetres wide and two metres apart. This let them filter out the atmospheric effects that usually trouble ground-based experiments.

Following the success of the work the British Government has agreed to fund a pounds 2.5m array of 10 such antennae, which will be based on Mount Teide in Tenerife. The new telescope, known as the "Very Small Array", will be used to help to answer more detailed questions - about the age of the universe, its rate of expansion, and two key questions: how much unseen, or "dark", matter is out there, and how the galaxies formed at all.

The red comet, page 11

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