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BLACK HOLES ARE A REALITY, SCIENTISTS SAY

SHARE BLACK HOLES ARE A REALITY, SCIENTISTS SAY

The strange and awesome cosmic phenomenon known as a supermassive black hole has moved from the realm of theory to reality with observations announced Wednesday by astronomers using the Hubble Space Telescope.

A supermassive black hole is a gravitational monster that gobbles up everything around it and is so powerful that no light or matter can escape.The astronomers reported finding what they said was conclusive evidence for the existence of an extraordinarily powerful black hole in the center of the giant elliptical galaxy M87, which is 50 million light-years away in the constellation Virgo.

This attractive force of collapsed matter weighs as much as 3 billion suns but is concentrated in a space no larger than the solar system.

The discovery appeared to lay to rest any remaining skepticism about black holes, predicted by Albert Einstein as part of his general theory of relativity. Over the past three decades, they were the ultimate goal of astrophysics, objects searched for with zeal but seemingly forever out of reach.

While scientists theorized and searched, the concept became so widely intriguing and expressive that it crossed into popular culture. The very term black hole has entered everyday language as an all-purpose metaphor.

In their excitement, astronomers were calling the Hubble observations the decisive clue needed to solve the mystery of the tremendous energies and gravitational forces at the cores of many galaxies.

They called the M87 black hole the most significant discovery made so far by the Hubble telescope, which had its vision enhanced with new optics installed by space-shuttle astronauts last December.

At a news conference at the NASA offices in Washington, Dr. Holland Ford, an astronomer at Johns Hopkins University and the Space Telescope Science Institute in Baltimore, said, "This is conclusive evidence of a supermassive black hole."

Observations and calculations of a whirlpool of hot gases toward the center of M87 were the basis for the black hole discovery. The gases formed a surprisingly well-ordered disk, like a pancake, that stretched across a distance of 500 light-years.

The disk reached within 60 light-years of the galactic nucleus. The energy released by gas falling into the black hole also produces a beam or jet of electrons spiraling outward at nearly the speed of light.

Dr. Daniel Weedman, the space agency's director of astrophysics, who had been skeptical of previous evidence regarding black holes, said he was now convinced of their existence. "This is a tremendous breakthrough," he said. "I do believe there is a black hole there."

Dr. Tod R. Lauer, an astronomer at Kitt Peak National Observatory in Arizona, whose previous studies of M87 provided strong but not quite conclusive evidence for black holes, praised the new findings.

"From my point of view," he said, "this is really it. It really hangs together and is very exciting."

For astronomers who were already believers before the confirming evidence was in hand, the discovery may have come as something of an anticlimax. They could not imagine any way other than a black hole that so much mass could be crammed in such a relatively small space.

Last year, Dr. John L. Tonry, an astronomer at Massachusetts Institute of Technology, said, "Astronomers are 99.9 percent sure that black holes exist."

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ADDITIONAL INFORMATION

Black holes and warped space

Scientists announced on Wednesday the discovery of a super massive black hole at the center of the galaxy M87, 50 million light-years away in the constellation Virgo.

Digging a gravity well

Einstein's 1915 General Theory of Relativity predicted that the gravity of massive objects warps space and time. If space is represented by a flat sheet, the warping caused by gravity can be visualized as a well or depression. The more massive the object, the more powerful is its gravity and the deeper the resulting well.

A "hole" in space

When an object becomes massive and dense enough, it collapses. The elementary particles of matter become crushed into each other until the forces that normally keep them apart are overwhelmed and all the matter is compressed into a point called a singularity. When that happens, the object is said to have become a black hole. Its powerful gravity traps anything that falls into it, even light.

Telescopic view of a black hole

The Hubble telescope revealed at the center of galaxy M87 a disk rotating at 1.2 million mph. Scientists think nothing but a black hole with the mass of 2.3 billion suns could keep the disk spinning at that rate.

Source: NASA; The Cambridge Atlas of Astronomy