Posted by Vishva News Reporter on March 11, 2004


A black hole is an object with a gravitational field so strong that its escape velocity exceeds the speed of light. In other words, a black hole is an object whose mass and size are such that nothing, not even light, can escape its gravity, hence the term "black" hole. The term was coined by theoretical physicist John Wheeler in 1967 [1], but the concept was developed, on the basis of Newtonian gravity, by the French mathematician Pierre Laplace in 1796.

Black holes are believed to form from the gravitational collapse of astronomical objects containing two or more solar masses. Astronomical observations suggest that the centers of most galaxies, including our own Milky Way, contain super-massive black holes containing millions to billions of solar masses.

Black holes are predictions of Einstein's theory of general relativity. In particular, they occur in the Schwarzschild metric, one of the earliest and simplest solutions to Einstein's equations, found by Karl Schwarzschild in 1915. This solution describes the curvature of space-time in the vicinity of a static and spherically symmetric object. For more information on BLACK HOLES please go to Wikipedia: BLACK HOLES by clicking on the  preceding red hilite...

Now there is some proof of existence of BLACK HOLES as described below....

FEBRUARY 18, 2004: NASA:

COSMIC REALITY SHOW: A STAR MEETS BLACK HOLE (you can read this article by clicking on NASA WEBSITE - especially if you do not see the photos of the star being ripped apart by a black hole)

Giant Black Hole Rips Apart Unlucky Star In Cosmic Reality Show

Image left: An illustration, top, depicts the catastrophic destruction of a star by a black hole, an event confirmed by observations from two X-ray Observatories: NASA's Chandra, bottom left, and ESA's XMM-Newton, bottom right. Credit: Illustration: NASA/CXC/M.Weiss; X-ray: NASA/CXC/MPE/S.Komossa et al.; Optical: ESO/MPE/S.Komossa.

Thanks to two orbiting X-ray observatories, astronomers have the first strong evidence of a supermassive black hole ripping apart a star and consuming a portion of it.

The event, captured by NASA's Chandra and ESA's XMM-Newton X-ray Observatories, had long been predicted by theory, but never confirmed.

Please click on the next line to continue reading............

Astronomers believe a doomed star came too close to a giant black hole after being thrown off course by a close encounter with another star. As it neared the enormous gravity of the black hole, the star was stretched by tidal forces until it was torn apart. This discovery provides crucial information about how these black holes grow and affect surrounding stars and gas.

"Stars can survive being stretched a small amount, as they are in binary star systems, but this star was stretched beyond its breaking point," said Stefanie Komossa of the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany, leader of the international team of researchers. "This unlucky star just wandered into the wrong neighborhood."

While other observations have hinted stars are destroyed by black holes (events known as "stellar tidal disruptions"), these new results are the first strong evidence. Evidence already exists for supermassive black holes in many galaxies, but looking for tidal disruptions represents a completely independent way to search for black holes. Observations like these are urgently needed to determine how quickly black holes can grow by swallowing neighboring stars.

Observations with Chandra and XMM-Newton, combined with earlier images from the German Roentgen satellite, detected a powerful X-ray outburst from the center of the galaxy RXJ1242-11. This outburst, one of the most extreme ever detected in a galaxy, was caused by gas, heated to millions of degrees Celsius, from the destroyed star being swallowed by the black hole. The energy liberated in the process was equivalent to a supernova.

"Now, with all the data in hand, we have the smoking gun proof that this spectacular event has occurred," said coauthor Guenther Hasinger, also of MPE.

The black hole in the center of RXJ1242-11 is estimated to have a mass of about 100 million times Earth's sun. By contrast, the destroyed star probably had a mass about equal to the sun, making it a lopsided battle of gravity. "This is the ultimate David versus Goliath battle, but here David loses," said Hasinger.

The astronomers estimated about one percent of the star's mass was ultimately consumed, or accreted, by the black hole. This small amount is consistent with predictions the momentum and energy of the accretion process will cause most of the destroyed star's gas to be flung away from the black hole.

The force that disrupted the star in RXJ1242-11 is an extreme example of the tidal force caused by differences in gravity acting on the front and back of an object. The tidal force from the moon causes tides in Earth's oceans. A tidal force from Jupiter pulled Comet Shoemaker-Levy apart, before it plunged into the giant planet.

The odds stellar tidal disruption will happen in a typical galaxy are low, about one in 10,000 annually. If it happened at the center of the Milky Way Galaxy, 25,000 light-years from Earth, the resulting X-ray outburst would be about 50,000 times brighter than the brightest X-ray source in our galaxy, beside the sun, but it would not pose a threat to Earth.

Other dramatic flares have been seen from galaxies, but this is the first studied with the high-spatial resolution of Chandra and the high-spectral resolution of XMM-Newton. Both instruments made a critical advance. Chandra showed the RXJ1242-11 event occurred in the center of a galaxy, where the black hole lurks. The XMM-Newton spectrum revealed the fingerprints expected for the surroundings of a black hole, ruling out other possible astronomical explanations.

Information and images about the event are available on the Internet at:
Donald Savage
Headquarters, Washington
(Phone: 202/358-1547)

Guido De Marchi
ESA Science Communications, Netherlands
(Intl. Phone: 31/71-565-3273)

Megan Watzke
Chandra X-ray Observatory Center, Cambridge, Mass.
(Phone: 617/496-7998)

February 18, 2004
RELEASE : 04-061


There are 0 additional comments.


Send your news items to be posted to

If you have any questions or comments about this web site, send mail to Bhavin Mistry.    
1997-2003 Prajaapati Vishva Aashram Foundation.    
Site Design by Helios Logistics Inc.