Wednesday, June 16, 2010

Science is never settled

Why everything we know about the dark side of the universe may be wrong

June 15, 2010

Lesley Ciarula Taylor

What we believe about the dark side of the universe may be wrong, concludes startling new research published by the Royal Astronomical Society.

Graduate student Utane Sawangwit and professor Tom Shanks of Durham University in England examined data from a satellite probe that studies heat left over from the Big Bang. In research published by the society this month, they found mistakes in the way the data were read.

Scientists have long estimated that 74 per cent of the universe is composed of dark energy and 22 per cent is dark matter, with the rest normal matter – even while admitting there’s no proof, and no one is even sure what dark energy and dark matter are.

“That theory makes many scientists uncomfortable because of our lack of understanding of what dark energy and dark matter are,” Sawangwit told the Star.

By using new methods to measure the “ripples” in the Cosmic Microwave Background created by the heat, he and Shanks answer that problem by saying that mysterious substances just aren’t there.

What is the universe made up of instead? “Normal cosmic matter,” said Sawangwit.

“We’re not proposing any new theory. We’re recalculating the data.”

What are the consequences? Dark energy pushes the universe to keep expanding. Less dark matter, less expansion. “Other than that,”according to NASA, “it’s a complete mystery.”

“This would challenge greatly our assumptions about the long-term future of the universe, because the assumption at the moment is that the universe is expanding,” said Dr. Robert Massey, of the Royal Astronomical Society. “If it isn’t, that would be a huge shock.”

Challenging fundamental beliefs among astronomers isn’t done lightly, the graduate student said. The research has been peer-reviewed, subject to society scrutiny, and carefully analyzed by NASA, which built the Wilkinson Microwave Anistropy Probe that first measured the residue of the Big Bang.

“I’m quite confident of the data,” Sawangwit said. “We spent half a year running checks.”

Previous measurements of the cosmic background bounced the signal off Jupiter. He and Shanks used a telescope to pick up radio galaxies.

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