The only possibilities that we know that would place that much matter in such a small volume are black holes and neutron stars, and the consensus is that neutron stars can't be more massive than about 3 solar masses.įrom frequently asked questions, What evidence do we have for the existence of black holes?, first in a Google search:Īstronomers have found convincing evidence for a supermassive black hole in the center of our own Milky Way galaxy, the galaxy NGC 4258, the giant elliptical galaxy M87, and several others. This suggests a source not larger than a light-millisecond or 300 km, so it is very compact.
This X-ray source exhibits rapid variations, with time scales on the order of a millisecond. This is of course not a proof of a black hole - but it convinces most astronomers.įurther evidence that strengthens the case for the unseen object being a black hole is the emission of X-rays from its location, an indication of temperatures in the millions of Kelvins. The calculated mass of the dark object is 8-10 solar masses much too massive to be a neutron star which has a limit of about 3 solar masses - hence black hole.
Black hole at center of universe plus#
Using the period plus spectral measurements of the visible companion's orbital speed leads to a calculated system mass of about 35 solar masses. So something massive but non-luminous is there (neutron star or black hole).ĭoppler studies of the blue supergiant indicate a revolution period of 5.6 days about the dark object.
X-ray sources are candidates for black holes because matter streaming into black holes will be ionized and greatly accelerated, producing x-rays.Ī blue supergiant star, about 25 times the mass of the sun, was found which is apparently orbiting about the x-ray source. For example:ĭoppler studies of this blue supergiant in Cygnus indicate a period of 5.6 days in orbit around an unseen companion.Īn x-ray source was discovered in the constellation Cygnus in 1972 (Cygnus X-1). The suspicion of the existence of a black hole comes from kinematic irregularities in orbits. X rays are also emitted if the acceleration of the charged particles if high, as is expected by a black hole attractive sink. This is not absolutely correct in the sense that visible light is emitted during the capture of charged matter from the radiation as it is falling into the strong gravitational potential of the black hole, but it is not strong enough to characterize a discovery of a black hole. What caused the dormant black hole to erupt so suddenly is unclear, but the scientists have suggested that it might have been a large gas cloud or a massive star, both of which would have fed Sagittarius A* with enough material for a flare-up.Black holes cannot be seen because they do not emit visible light or any electromagnetic radiation. "To get an idea of the increase in intensity of the X-ray emission when the black hole emerged from its quiescent state, it is as if a single glow-worm hidden in a forest suddenly became as bright as the Sun," the researchers wrote. By measuring the polarization of these X-rays using NASA's Imaging X-ray Polarimetry Explorer satellite, researchers narrowed down the glow's age and origin: a powerful X-ray pulse arriving at Earth from Sagittarius A* 200 years ago.
Hints of the monster black hole's awakening first appeared 30 years ago, when X-rays were detected among the glow given off by the galactic center's gas clouds. If black holes grow large enough, friction causes the material spiraling into their maws (called an accretion disk) to heat up so much that they can outshine entire galaxies as they fire out powerful beams of high-energy X-rays. Black holes may be swallowing invisible matter that slows the movement of starsīlack holes are born from the collapse of giant stars and grow by ceaselessly gorging on gas, dust, stars and other black holes in the star-forming galaxies that contain them. 1st image of our galaxy's 'black hole heart' unveiled James Webb Space Telescope discovers oldest black hole in the universe - a cosmic monster 10 million times heavier than the sun
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