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Astronomers Say Universe May Be Bigger and Older

August 05, 2006|John Johnson Jr. | Times Staff Writer

New findings from an Ohio State University team of astronomers are raising the possibility that the universe is larger than previously thought.

Using new measurement methods, the team found that the Triangulum Galaxy is 3 million light-years away, not the 2.6 million that had been accepted in the past.

If the method proves reliable for other distant objects, the results could force a readjustment of one of the building blocks of modern cosmology: the Hubble constant.

"The Hubble constant used to be the one parameter that we knew pretty well. Now it's lagging behind," said Krzysztof Z. Stanek, a coauthor of a paper describing the new work, scheduled to appear in the Astrophysical Journal.

For 80 years, the Hubble constant has been used to calculate how far away objects are in the universe. The constant uses a series of measurements, including differences in light intensity and changes in the "red shift," which measures how far the light from a distant star is shifted toward the red end of the light spectrum. The greater the red shift, the farther away the object is and the faster it is traveling.

A readjusted Hubble constant would make the observable universe about 15% larger than some current estimates, which range from a radius of 46 billion light-years to 78 billion light-years, according to recent calculations.

The estimated age of the universe would also increase, to about 16 billion years old from the current 13.7 billion years.

The new method employs a variety of telescopes scanning in the optical and infrared ranges.

Peter Eisenhardt, a scientist at the Jet Propulsion Laboratory in La Canada Flintridge specializing in galaxy evolution, called the paper a "pretty solid piece of work."

But he cautioned that it would be premature to change the model of the universe based on a single study. He also said interstellar dust might be interfering with the light from Triangulum, making it appear farther away than it really is. The Ohio team took dust into consideration but used a slightly different method to estimate its impact on distance calculations, Eisenhardt said.

The new finding wouldn't challenge the basic model of a rapidly expanding universe.

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