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Black-hole physics · 3 Schwarzschild radii (non-spinning)

The Innermost Stable Circular Orbit

The closest orbit around a black hole in which matter can circle stably — at three Schwarzschild radii for a non-spinning black hole, and closer for a rapidly spinning one. Inside it, matter spirals inevitably inward. The ISCO sets the inner edge of an accretion disk and thus how much energy accretion can release.

Highlights

  • The inner edge of an accretion disk

Across compact objects

Knowledge connections

Sources

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.