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Picture of black hole within reach

By Blake Smith
Arizona Daily Wildcat,
January 31, 2000
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With improvements in scientific techniques, researchers expect to have a picture of our universe's massive black hole within 10 years, according to a UA physics professor.

University of Arizona physics professor Fulvio Melia and researchers from Johns Hopkins University and the Max Planck Institute in Germany are working together to take a picture of the never-before-photographed black hole.

The scientists are using the Very Large Baseline Interferometry, a network of radio telescopes spread across the surface of the Earth which focus on distant objects, to capture a photo of the large mass.

According to Melia, the VLBI is very effective on focusing in on celestial objects near Earth, but the system of telescopes would have difficulty capturing a clear image of the black hole, located about 26,000 light-years away.

"We need to improve zooming capabilities by a factor of three or four," Melia said Friday.

He added that scientists "need to (take the telescopes) to higher frequencies," which could give a clearer picture by eliminating the distortion of dust and gas between Earth and the black hole.

Melia admits being able to focus on the large mass may be difficult, because the network of VLBI telescopes may not be spread far enough apart.

"We have limitations ... namely the size of the Earth," he said.

The photo is expected to have a shadowing effect, which could give scientists extensive information about the mysterious black hole.

"The observation of this shadow would confirm the widely held belief that most of the dark mass concentration in the nuclei of galaxies such as ours is contained within a black hole, and it would be the first direct evidence of the existence of an event horizon," according to the researchers' January paper on black hole shadowing.

The black hole's center - or event horizon - is responsible for sucking objects to the point-of-no-return.

"The experiment that we propose here should be a major motivation for intensifying the current development of submillimeter astronomy in general, and millimeter and submillimeter VLBI in particular," the paper stated.

When the picture is taken, scientists will know more about the properties of the black hole, according to Melia.

The photo will give scientists conclusive proof that a massive black hole exists at the center of our universe, and could confirm theories of optical distortion in space because of the rotation of the black hole, Melia said.

"(The picture) could open the possibility of understanding other galactic nuclei," he added.

Melia said black holes are a collapse of matter into a compact region, which results from the explosion of a star.

"They are so dense that its gravity overwhelms everything, including light," he added. "Nothing can escape it."

Scientists estimate the black hole in the center of the Milky Way has consumed more than two million suns worth of gas and dust, and has a radius of more than 12 suns, according to Melia.

Nearly 1 million black holes span across the Milky Way, each about the mass of the sun.

Those might sound massive, but in a galaxy more than 50 million light-years away from Earth, there is a black hole with a mass equal to 3 billion of our suns.

The project is funded by NASA, the National Science Foundation, and DFG - the German version of the National Science Foundation.

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