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Hawking radiation is the theoretical emission released outside a black hole 's event horizon. This is counterintuitive because once ordinary electromagnetic radiation is inside the event horizon, it cannot escape. It is named after the physicist Stephen Hawking, who developed a theoretical argument for its existence in 1974. [ 1 ]
t. e. Stephen William Hawking (8 January 1942 – 14 March 2018) was an English theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge. [6][17][18] Between 1979 and 2009, he was the Lucasian Professor of Mathematics at Cambridge, widely viewed as one of ...
This idea suggests that Hawking radiation stops before the black hole reaches the Planck size. Since the black hole never evaporates, information about its initial state can remain inside the black hole and the paradox disappears. But there is no accepted mechanism that would allow Hawking radiation to stop while the black hole remains macroscopic.
Hawking radiation is in a pure state. The black hole can be thought of as a quantum operator, which takes the quantum state of the original mass and converts it into the quantum state of the Hawking radiation, as viewed by a distant observer. Outside of the black hole's event horizon, semi-classical field equations remain valid.
At present, it is expected by the Hawking radiation mechanism that the primary impact of quantum effects is for event horizons to possess a temperature and so emit radiation. 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.
A Brief History of Time: From the Big Bang to Black Holes is a book on theoretical cosmology by the physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for readers who had no prior knowledge of physics. In A Brief History of Time, Hawking writes in non-technical terms about the structure, origin, development and ...
v. t. e. The Penrose–Hawking singularity theorems (after Roger Penrose and Stephen Hawking) are a set of results in general relativity that attempt to answer the question of when gravitation produces singularities. The Penrose singularity theorem is a theorem in semi-Riemannian geometry and its general relativistic interpretation predicts a ...
Followed by. On The Shoulders of Giants. The Universe in a Nutshell is a 2001 book about theoretical physics by Stephen Hawking. [1][2] It is generally considered a sequel and was created to update the public concerning developments since the multi-million-copy bestseller A Brief History of Time was published in 1988.