US scientists fall into beige Universe study

By ANNE BESTON

Astronomers have said they made a mistake in determining the colour of the universe - it's more beige than green.

American scientists at Johns Hopkins University announced in January that the universe was turquoise but now say their calculations were flawed and the colour is more likely a shade of beige.

That's how the universe would appear to someone "standing" outside it and seeing all its light.

Assistant professor of astronomy at the university, Dr Karl Glazebrook, apologised for getting the colour wrong.

"It's our fault for not taking the colour science seriously enough," he said.

Although Dr Glazebrook's original calculations caused widespread interest among astronomers and space enthusiasts, it was originally just a footnote to a comprehensive survey of the spectrum of light emitted by 200,000 galaxies.

Dr Glazebrook and postdoctoral fellow Dr Ivan Baldry, set out to compile a "cosmic spectrum" based on data gathered by the Australian 2dF Galaxy Redshift Survey.

The Redshift Survey is a team of 30 international researchers from Australia and the United Kingdom who measure the distances to far-off galaxies using Australia's largest telescope, the 3.9m Anglo-Australian Telescope, and an instrument called 2dF.

The 2dF detector allows astronomers to observe and analyse 400 objects at once, and on a long clear night, they can log the positions of more than 2000 galaxies.

The cosmic spectrum initially took the standard scientific form of a graph, but researchers transformed it into an array of colours, replacing each wavelength with the colour the human eye sees at that wavelength, and varying the intensity of the colour in proportion to that wavelength's intensity in the universe.

Dr Glazebrook decided to try and calculate how the spectrum would appear to a human eye - to find out what colour the universe is.

He came up with a colour a few per cent greener than pale turquoise. But shortly after that announcement, a scientist who helped convert Dr Glazebrook's findings into a colour, said the computer programme used in the project had mistakenly set a feature known as the "white point". The white point is the point at which light appears white given the environment the light is viewed in.

Once the white point was adjusted to calculate the perceptions of an observer looking at the light in a darkened environment, the colour of the universe came out beige.

When the viewing environment was adjusted to daylight, the colour was a faint red; in indoor light, it shifted to blue.

The laboratory that helped Dr Glazebrook come up with turquoise plans later this year to imitate with scientific accuracy the wavelengths of the colour of the universe.

Then people can sit down in front of the light and decide what colour it is.

Color of the Universe Corrected by Astronomers