A light bounce: Students stand beside a giant cardboard kangaroo at Monash University as a NASA satellite photograps it. The goal of the experiment is to help scientists measure the Earth's albedo - its ability to reflect sunlight into space.

Credit: AFP

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MELBOURNE: A giant white kangaroo bounced into the science books on Tuesday as part of a global experiment to measure 'albedo', or the amount of light the Earth reflects back to space.

The cardboard cut-out marsupial, which measured 32 m by 18 m, was laid out in a paddock on the grounds of Monash University in the southern Australian city of Melbourne.

"We call it our kangaroo from space because two satellites flew over (and) what they were doing was measuring the amount of light reflected from our kangaroo," said Patricia Vickers-Rich director of the Monash Science Centre. "And the point of that was to make people aware that reflected light, or lack of reflected light, has a very big effect on climate."

Reflecting on a problem

Scientists are concerned that the melting of the polar ice caps, happening at a faster rate than expected, is quickly robbing the Earth of some of the vast white spaces, which have traditionally reflected the Sun's rays.

"If something is white it reflects a lot of light, if something is dark it absorbs it, and that will affect the temperature of our atmosphere," Vickers-Rich said. "If we reflect less of the Sun's energy and we absorb it, then our temperatures will rise. And they are rising, there's no doubt about it."

She said the white kangaroo experiment is one of 20 such tests being conducted around the world in collaboration with U.S. space agency NASA and the International Action on Global Warming network of science centres.

Between the 15 and 24 May, students participating in The Albedo Experiment will lay out white tiles to create "miniature mock ice caps" to highlight changes in the amount of light reflected by the earth over the past year.

The academic, also a palaeontologist, said the Melbourne group was the first to make their white reflector into an animal. "We were supposed to put out a square... and we thought, 'Well, why don't we do an animal?"

A giant koala and a massive lizard were discussed before it was decided "everybody recognises the kangaroo," she said.