Universe is off colour

The new colour: Mmm... interesting

Oops, the Universe is not turquoise - it is off-white.

Researchers who tried to gauge what the eye might see if it were tuned to all the light coming from thousands of galaxies have admitted to a mistake with the software they used to make the calculation.

If we make mistakes, we admit them

Dr Karl Glazebrook

They say the software was set up wrongly, making the Universe more colourful than it really is.

"It's much closer to white, really," said Ivan Baldry, a post-doctoral fellow at Johns Hopkins University, US. "More like cream."

Dr Baldry made the turquoise announcement in January with Dr Karl Glazebrook. The Hopkins scientists said they were alerted to the error by colour engineers who checked the software.

The joke's on you

"It is embarrassing," said Dr Glazebrook. "But this is science. We're not like politicians. If we make mistakes, we admit them. That's how science works."

The pair determined the cosmic colour by combining light from over 200,000 galaxies within two billion light-years of Earth. The data had come from the Australian 2dF Galaxy Redshift Survey at the Anglo-Australian Observatory in New South Wales, Australia.

The colour that wasn't

By giving a numeric value to the colours of the different galaxies, adding them together and then averaging them, they came up with their colour, which they dubbed cosmic spectrum green.

The activity was supposed to be an amusing footnote to a serious astronomical paper, but the media liked it and ran the story with big headlines.

Then, the Munsell Color Science Laboratories at the Rochester Institute of Technology in New York, US, contacted the researchers to tell them they had incorrectly set a feature known as the "white point".

Serious stuff

The white point is the point at which light appears white to the human eye in different kinds of illumination. The Hopkins astronomers' white point was redder than it should have been, and this skewed their result.

Munsell Color Science Laboratories is now working with Drs Baldry and Glazebrook to produce more impressions of the colour of the Universe.

Good luck if you can see the difference between this colour and white!

Baldry and Glazebrook

"The mistake took some time to realise and track down," the team said on its website. "Only a handful of colour scientists had the expertise to spot the error. One moral of this story is we should have paid more attention to the 'colour science' aspect and had that refereed as well."

The website updates the researchers' earlier findings. It shows a patch of colour that to the casual observer will seem, well, white.

"Good luck if you can see the difference between this colour and white!" they write. "Suggestions for the name are welcome. As long as it is not beige!"

The serious research the two men were doing? It was about using the light from stars of different ages to try to work out how the rate of star-birth might have changed over time.