Black hole fails to do its job

Astronomers have discovered what can happen when a giant black hole does not intervene in the life of a galaxy cluster. Using NASA's Chandra X-ray Observatory and other telescopes they have shown that passive black hole behavior ...

Unequal neutron-star mergers create unique 'bang' in simulations

When two neutron stars slam together, the result is sometimes a black hole that swallows all but the gravitational evidence of the collision. However, in a series of simulations, an international team of researchers including ...

Runaway star might explain black hole's disappearing act

At the center of a far-off galaxy, a black hole is slowly consuming a disk of gas that swirls around it like water circling a drain. As a steady trickle of gas is pulled into the gaping maw, ultrahot particles gather close ...

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Black hole

In general relativity, a black hole is a region of space in which the gravitational field is so powerful that nothing, including light, can escape its pull. The black hole has a one-way surface, called an event horizon, into which objects can fall, but out of which nothing can come. It is called "black" because it absorbs all the light that hits it, reflecting nothing, just like a perfect blackbody in thermodynamics. Quantum analysis of black holes shows them to possess a temperature and Hawking radiation.

Despite its invisible interior, a black hole can reveal its presence through interaction with other matter. A black hole can be inferred by tracking the movement of a group of stars that orbit a region in space which looks empty. Alternatively, one can see gas falling into a relatively small black hole, from a companion star. This gas spirals inward, heating up to very high temperature and emitting large amounts of radiation that can be detected from earthbound and earth-orbiting telescopes. Such observations have resulted in the scientific consensus that, barring a breakdown in our understanding of nature, black holes do exist in our universe.

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