One such supermassive black hole, Sagittarius A*, exists at the centre of the Milky Way Galaxy.
Ferrarese (Johns Hopkins University) and the National Aeronautics and Space Administration Hubble Space Telescope image of an 800-light-year-wide spiral-shaped disk of dust fueling a massive black hole in the centre of galaxy NGC 4261, located 100 million light-years away in the direction of the constellation Virgo. Accordingly, the collapse of millions or billions of solar masses of interstellar gas under gravitational force into a large black hole would account for the enormous energy output of quasars and certain galactic systems. A mass of gas falling rapidly into a black hole is estimated to give off more than 100 times as much energy as is released by the identical amount of mass through nuclear fusion. Various astronomers have speculated that large volumes of interstellar gas collect and collapse into supermassive black holes at the centres of quasars and galaxies. Some black holes apparently have nonstellar origins. Discovered in 1971 in the constellation Cygnus, this binary consists of a blue supergiant and an invisible companion 14.8 times the mass of the Sun that revolve about one another in a period of 5.6 days. One of the component stars of the binary X-ray system Cygnus X-1 is a black hole. For example, if a black hole is a member of a binary star system, matter flowing into it from its companion becomes intensely heated and then radiates X-rays copiously before entering the event horizon of the black hole and disappearing forever. They can be “observed,” however, by the effects of their enormous gravitational fields on nearby matter. Stars with a smaller amount of mass evolve into less compressed bodies, either white dwarfs or neutron stars.īlack holes usually cannot be observed directly on account of both their small size and the fact that they emit no light. Only the most massive stars-those of more than three solar masses-become black holes at the end of their lives. If you can finish it in less than 15 minutes, you’re a master of the universe! For a black hole with a mass 10 times as great as that of the Sun, the radius would be 30 km (18.6 miles).Įver wanted to visit everything in outer space in only 25 minutes? Now you can with this quiz, which will rocket you from planets to black holes to artificial satellites. The size of the Schwarzschild radius is proportional to the mass of the collapsing star. The radius of the event horizon is called the Schwarzschild radius, after the German astronomer Karl Schwarzschild, who in 1916 predicted the existence of collapsed stellar bodies that emit no radiation. Inside the event horizon the escape velocity (i.e., the velocity required for matter to escape from the gravitational field of a cosmic object) exceeds the speed of light, so that not even rays of light can escape into space.
The singularity constitutes the centre of a black hole and is hidden by the object’s “surface,” the event horizon. See all videos for this articleĭetails of the structure of a black hole are calculated from Albert Einstein’s general theory of relativity. Created and produced by QA International. The intense gravitational force that they exert allows nothing to escape.
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