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I've long been wondering how this is possible: two black holes circling around each other.
Black holes are singularities, and space is 3-D. No dance pattern between the two should have
priority. Indeed, they should merge... and they do!
Astrum on Black Holes:
Part 1
Gemini:
What refinements to black hole theory did Stephen Hawkins bring?
Stephen Hawking’s work fundamentally shifted the study of black holes from pure geometry and general relativity into the realm of thermodynamics and quantum mechanics. His refinements proved that black holes are not truly "black" or eternal, but are dynamic, thermal objects.
1. Hawking Radiation: The End of Eternal Black Holes
Before Hawking, it was believed that nothing—not even light—could ever leave a black hole, meaning they would only ever grow. In 1974, Hawking applied quantum field theory to the curved space-time around a black hole and discovered that they must emit radiation.
This happens because "empty" space is filled with virtual particle pairs that constantly pop in and out of existence. Near an event horizon, one particle can fall in while the other escapes. To an outside observer, it looks like the black hole is emitting a particle and losing a tiny amount of mass.
The Refinement: Black holes have a temperature and will eventually evaporate completely over vast timescales.
2. The Area Theorem
In 1971, Hawking proposed the Area Theorem, which states that the total surface area of a black hole’s event horizon can never decrease. This held true even when two black holes merged; the new event horizon's area must be greater than or equal to the sum of the original two.
The Refinement: This provided a mathematical "one-way street" for black hole evolution, similar to how entropy always increases in a closed system. This theorem was famously confirmed observationally for the first time in 2021 using gravitational wave data from LIGO.
3. Black Hole Thermodynamics
Working with colleagues like Brandon Carter and James Bardeen, Hawking helped formulate the Four Laws of Black Hole Mechanics. These laws are direct analogs to the laws of thermodynamics:
Zeroth Law: The "surface gravity" is constant over the horizon of a stationary black hole (like temperature in thermal equilibrium).
First Law: Relates changes in mass to changes in area, angular momentum, and charge (analogous to energy conservation).
Second Law: The area of the horizon never decreases (analogous to the law of increasing entropy).
The Refinement: This turned black hole physics into a branch of heat and energy science, eventually leading to the Bekenstein-Hawking Entropy formula, which suggests a black hole's "information" is stored on its 2D surface area rather than its 3D volume.
4. The Information Paradox
Perhaps Hawking's most famous "refinement" was actually a problem he created: the Information Paradox. If a black hole evaporates and disappears, what happens to the information (the specific quantum states) of the objects that fell in?
The Conflict: General relativity says the information is gone, but quantum mechanics says information can never be destroyed.
Hawking’s Later Evolution: Initially, Hawking argued information was lost. However, in his later years (and specifically in a 2016 paper on "Soft Hair"), he refined his stance, suggesting that information might be stored in low-energy excitations (soft hair) at the event horizon and could potentially escape as the black hole evaporates.
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