Black Holes
A black hole is a region of space time from which gravity prevents anything, including light, from escaping. Around a black hole, there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.
Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Mitchell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958.
Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe.
Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Mitchell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958.
Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe.
| Class | Mass | Size |
|---|---|---|
| Supermassive black hole | ~105–1010 MSun | ~0.001–400 AU |
| Intermediate-mass black hole | ~103 MSun | ~103 km ≈ REarth |
| Stellar black hole | ~10 MSun | ~30 km |
| Micro black hole | up to ~MMoon | up to ~0.1 mm |
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