Part 1 of 5 · freeIntroduction
A black hole is a region of spacetime, the fabric that ties space and time together, where gravity is so intense that the speed needed to escape is greater than the speed of light. Nothing leaves it: no matter, no light.
It is not a “hole” in the sense of a tunnel. It is an extreme concentration of matter that bends that fabric very hard. For a long time black holes were pure theory, a result of Einstein's equations. Today they are observed in several ways.
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- 2When a star collapses
- 3Not a cosmic vacuum cleaner
- 42019: the first image
- 5Hawking and the slow evaporation
Open-book quiz8 questions whose answers are in the text.
Glossary10 terms explained in a tap.
30 languagesThe same course, from French to Japanese.
