Stellar Pancake

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Pity the poor star that wanders too close to a supermassive black hole. Not only will the star be flattened, stretched, and eaten, it might explode, too.

Supermassive black holes lurk at the hearts of many galaxies, including our own. They can range from a few million to a few billion times the mass of the Sun.

If a star passes too close to a black hole of up to about a hundred million times the mass of the Sun, the black hole's gravity destroys the star. The side that's closest to the black hole feels a stronger tug than the opposite side, which stretches the star along its line of travel and squeezes it from top to bottom, flattening it like a pancake. Eventually, the star is pulled apart -- one bite at a time.

But recent research by astronomers at Paris Observatory suggests that the "squeezing" business could make the star explode. The intense pressure and heat would trigger runaway nuclear reactions that would quickly cause the star to blow itself apart. Some of the material would be blown free of the black hole's grip.

The astronomers say their simulations suggest that the explosion could create an intense outburst of X-rays or gamma-rays. The outburst could occur days or months before the star's remaining matter finally spiraled into the black hole. That would serve as an alert system -- letting astronomers know that a black hole is about to snack on the remains of a dead star.

More about black holes tomorrow.

Script by Damond Benningfield, Copyright 2008

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