SPACE.com -- SOHO measurements of the sun reveal a surface with hills and dales, much like ocean, say University of Hawaii researchers.

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	SOHO measurements of the sun reveal a surface with hills and dales, much like ocean, say University of Hawaii researchers. By Andrew Bridges Pasadena Bureau Chief posted: 07:00 pm ET 16 June 2000

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The most sensitive measurement ever made of a stars shape shows that our sun is speckled with tiny hills and dales, much like the surface of the ocean, University of Hawaii researchers said.

According to the teams work, reported in the June 1 issue of the journal Nature, the sun is covered with 330-foot (100-meter) high hills. Each hill lies a distant 56,000 miles (90,000 kilometers) from the next.

Using the SOHO spacecraft, a cooperative effort of the American and European space agencies, the Hawaii team spent three years measuring changes in the shape of the suns edge, or "limb," to detect the bumps.

Scientists hope that further study of the surface properties of the sun will cast light on the internal workings of other stars as well.

"This new understanding of the solar "mountains," which cover its surface will help us solve some longstanding mysteries, like why the sun rotates more slowly at the poles than at its equator. Rossby waves are a new and sensitive probe of the sun's peculiar interior rotation," said Jeffrey R. Kuhn, of the University of Hawaiis Institute for Astronomy, in a statement.

The team reports that the Rossby-wave phenomenon produces a grid of weak cyclones that in turn generate the delicate topographical features on the suns surface.

The suns rotation creates the long, slow waves, named for meteorologist Carl-Gustav Rossby. On Earth, the waves are seen in both the oceans and atmosphere, said William Patzert, a research oceanographer at NASAs Jet Propulsion Laboratory.

"For the Sun, it is interesting because it tells us that there are patterns in what seems to be a chaotic inferno," Patzert said.

SOHOs Michelson Doppler Imager captured the features by measuring minute changes in the position of the suns atmosphere at the limb.

As the sun rotated during that period of study, it carried with it the relatively minute Rossby-generated hills over the edge, where the team detected them over the course of their observations.

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