A detailed, all-sky image of the early cosmos has helped astronomers pin down the age of the universe, NASA scientists said Tuesday.

The map is like a baby picture of the most distant light in the universe, and the findings support the Big Bang theory, scientists say. "We determine the age of the universe to be 13.7 billion years old to within 200 million years," said principal investigator Charles Bennett of Goddard Space Flight Center. "That's about a margin of error of only one per cent."

Until now, scientists estimated the universe was 12 to 15 billion years old.

Cosmic portrait of the infant universe (red spots represent warm areas and blue spots cooler ones)Courtesy: NASA/WMAP Science Team

The results come from the Wilkinson Microwave Anisotropy Probe (WMAP) project.

For 12 months, the WMAP satellite scanned the entire sky up to 1.5 million kilometres from Earth.

The probe measured temperature fluctuations of a millionth of a degree in the cosmic microwave background – faint electromagnetic radiation from the early universe.

Simulation of WMAP satellite

According to their interpretation of the data, the universe cooled enough to allow the first stars to form only 200 million years after the Big Bang, the researchers said. Scientists had thought the first stars shone much later.

Pictures, data support standard model of universe

The study also found the early universe included four per cent matter in the form of atoms, about 23 percent unseen dark matter, and about 73 per cent mysterious dark energy, an unknown force that scientists think counteracts gravity and allows the universe to expand.

Atoms we can see (yellow portion) make up 4 per cent of universe

"That four per cent is the right stuff," said John Bahcall of Princeton University. "All the other stuff is goodness knows what."

Canadian astrophysicist Mark Halpern of the University of British Columbia is a member of the research team.

Halpern said the satellite will throw a light on both dark matter and dark energy.

"By continuing these measurements, by getting more precise pictures from this map, ... we'll be able to find out what the properties of that matter are," said Halpern.

The findings also offer evidence to support a theoretical model that the universe expanded rapidly during its first fraction of a second.

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WMAP will continue its observation for another three years.

Bennett and his colleagues have submitted 13 studies on the new data to The Astrophysical Journal.