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 ...

Telescopes show the Milky Way's black hole is ready for a kick

The supermassive black hole in the center of the Milky Way is spinning so quickly it is warping the spacetime surrounding it into a shape that can look like a football, according to a new study using data from NASA's Chandra ...

Einstein's description of gravity just got much harder to beat

Einstein's theory of general relativity—the idea that gravity is matter warping spacetime—has withstood over 100 years of scrutiny and testing, including the newest test from the Event Horizon Telescope collaboration, ...

A new view of all objects in the universe

The most comprehensive view of the history of the universe ever created has been produced by researchers at The Australian National University (ANU). The study also offers new ideas about how our universe may have started.

Novel theory of entropy may solve materials design issues

A challenge in materials design is that in both natural and manmade materials, volume sometimes decreases, or increases, with increasing temperature. While there are mechanical explanations for this phenomenon for some specific ...

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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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