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The episode presented an in-depth treatment of black holes, beginning with John Michell's suggestion of the existence of an "invisible star" to the first discovery of a black hole, Cygnus X-1. [2] The episode's title is an allusion to how light from stars and other cosmic objects takes eons to travel to Earth, giving rise to the possibility ...
John Michell (/ ˈ m ɪ tʃ əl /; 25 December 1724 – 21 April 1793) was an English natural philosopher and clergyman who provided pioneering insights into a wide range of scientific fields including astronomy, geology, optics, and gravitation.
In general relativity, a naked singularity is a hypothetical gravitational singularity without an event horizon.. When there exists at least one causal geodesic that, in the future, extends to an observer either at infinity or to an observer comoving with the collapsing cloud, and in the past terminates at the gravitational singularity, then that singularity is referred to as a naked ...
A black hole with the mass of a car would have a diameter of about 10 −24 m and take a nanosecond to evaporate, during which time it would briefly have a luminosity of more than 200 times that of the Sun. Lower-mass black holes are expected to evaporate even faster; for example, a black hole of mass 1 TeV/c 2 would take less than 10 −88 ...
Black holes, objects whose gravity is so strong that nothing—including light—can escape them, have been depicted in fiction since at least the pulp era of science fiction, before the term black hole was coined. A common portrayal at the time was of black holes as hazards to spacefarers, a motif that has also recurred in later works.
For black holes, this manifests as Hawking radiation, and the larger question of how the black hole possesses a temperature is part of the topic of black hole thermodynamics. For accelerating particles, this manifests as the Unruh effect , which causes space around the particle to appear to be filled with matter and radiation.
The singularity at the center of a Schwarzschild black hole is an example of a strong singularity. Space-like singularities are a feature of non-rotating uncharged black holes as described by the Schwarzschild metric, while time-like singularities are
Final parsec problem: Supermassive black holes appear to have merged, and what appears to be a pair in this intermediate range has been observed, in PKS 1302-102. [23] However, theory predicts that when supermassive black holes reach a separation of about one parsec, it may take billions of years to orbit closely enough to merge—greater than ...