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AsteriaStar
Astrophysical object

Black Hole

Cosmology & UniverseEstablished Science

Definition

A region of spacetime where gravity is so strong that nothing, not even light, can escape.

Scientific overview

A black hole forms when matter is compressed within its Schwarzschild radius, creating an event horizon. General relativity predicts them, and they are now confirmed through stellar orbits, X-ray binaries, gravitational waves, and direct imaging of their shadows.

Evidence

  • Orbits of stars around Sagittarius A*
  • Gravitational waves from black-hole mergers (LIGO)
  • Direct images of M87* and Sgr A* (EHT)

Open questions

  • What happens to information that falls in?
  • What is inside the event horizon?

Rests on

Related discoveries & objects

Related scientists

Knowledge connections

Sources & references

The primary and reference sources this topic draws on.

  • NASANational Aeronautics and Space Administration

    Mission data, planetary science, space telescopes, and public-domain imagery.

    Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.

  • Event Horizon TelescopeEvent Horizon Telescope Collaboration

    Horizon-scale images of supermassive black holes (M87*, Sagittarius A*).