A unique experiment to explore black holes

What happens when two supermassive black holes collide? Combining the observing power of two future ESA missions, Athena and LISA, would allow us to study these cosmic clashes and their mysterious aftermath for the first ...

Is dark matter made of axions? Black holes may reveal the answer

What is dark matter made of? It's one of the most perplexing questions of modern astronomy. We know that dark matter is out there, since we can see its obvious gravitational influence on everything from galaxies to the evolution ...

Forecasting the hunt for the first supermassive black holes

It is believed that the formation and growth of most galaxies across the history of the universe has been fueled by supermassive black holes growing together with their host galaxy as they collect matter to attain millions ...

Jets and winds from galaxy cores appear to share a common cause

Astronomers have a rough understanding of how galaxies emit jets from their cores. Galaxy cores also blow out winds of ionized gas, for which researchers lack a general explanation. SRON astronomers have now found a correlation ...

Telescopes in space for even sharper images of black holes

Astronomers have just managed to take the first image of a black hole, and now the next challenge facing them is how to take even sharper images, so that Einstein's Theory of General Relativity can be tested. Radboud University ...

Hubble spots a stunning spiral galaxy

Few of the universe's residents are as iconic as the spiral galaxy. These limelight-hogging celestial objects combine whirling, pinwheeling arms with scatterings of sparkling stars, glowing bursts of gas, and dark, weaving ...

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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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