- Also called Black Hole of Cal·cut·ta. a small prison cell in Fort William, Calcutta, in which, in 1756, Indians are said to have imprisoned 146 Europeans, only 23 of whom were alive the following morning.
- (lowercase) any usually wretched place of imprisonment or confinement.
Black Hole of Calcutta
- a small dungeon in which in 1756 the Nawab of Bengal reputedly confined 146 English prisoners, of whom only 23 survived
- informal, mainly British any uncomfortable or overcrowded place
- an object in space so dense that its escape velocity exceeds the speed of light
- any place regarded as resembling a black hole in that items or information entering it cannot be retrieved
in astrophysics, 1968, probably with awareness of Black Hole of Calcutta, incident of June 19, 1756, in which 146 British POWs taken by the Nawab of Bengal after the capture of Ft. William, Calcutta, were held overnight in punishment cell of the barracks (meant to hold 4 people) and all but 23 perished.
- An extremely dense celestial object whose gravitational field is so strong that not even light can escape from its vicinity. Black holes are believed to form in the aftermath of a supernova with the collapse of the star's core. See also event horizon. See more at star.
A Closer Look: When a very massive star ends its life in a supernova explosion, the remaining matter collapses in upon itself. If there is enough mass in this collapsed star, it becomes a black hole. A black hole is so dense that its gravitational forces are strong enough to prevent anything that comes close enough to the region known as the event horizon from escaping. Even light cannot escape, since the escape velocity (the velocity needed for an object to escape some larger object's gravitational field) necessary to escape a black hole is greater than the speed of light. Black holes are extremely dense: for the Sun, which has a diameter of about 1,390,000 kilometers (862,000 miles), to be as dense as a black hole, its entire mass would have to be squeezed down to a ball fewer than 3 kilometers (5 miles) across. Some theorists postulate that the material in a black hole may be compressed to a single point of infinite density called a singularity. Because astronomers cannot directly observe a black hole, they infer its existence from the effects of its gravitational pull. For example, when a black hole results from the collapse of one star in a binary star system, it attracts material from the remaining star. This material forms an accretion disk, which compresses and heats up until it emits detectable x-rays. Black holes are thought to reside in the centers of many galaxies, including our own Milky Way.
Black Hole of Calcutta
A cell in the jail of a British fort in Calcutta, India. In the middle of the eighteenth century, British and Indian troops clashed at the fort. The Indian troops drove a reported 146 defenders of the fort into the cell, which measured about fifteen by eighteen feet. Many had suffocated by the next morning.
In astronomy, an object so massive that nothing, not even light, can escape its gravitation. Black holes were given their name because they absorb all the light that falls on them. The existence of black holes was first predicted by the general theory of relativity. Supermassive black holes have been found in the centers of many galaxies. Stellar black holes are thought to arise from the death of very massive stars. Astronomers expect to find many stellar black holes in the Milky Way.
A wretched prison cell or other place of confinement. For example, The punishment is solitary confinement, known as the black hole. This term acquired its meaning in 1756 with the event known as the Black Hole of Calcutta. On the night of June 20, the ruler of Bengal confined 146 Europeans in a prison space of only 14 by 18 feet. By morning all but 23 of them had suffocated to death. Although historians since have questioned the truth of the story, it survives in this usage.
A great void or abyss. For example, Running a single small newspaper ad to launch a major campaign is useless; it amounts to throwing our money into a black hole. This usage alludes to a region, so named by astronomers, whose gravitational field is so intense that no electromagnetic radiation can escape from it. [Late 1970s]