Black hole radius
Calculate the Schwarzschild radius for a black hole of a chosen mass.
Your experiment
How it works
The event horizon is a boundary in spacetime, not a material surface. For a non-rotating, uncharged black hole, its radius grows linearly with mass.
Read the field note ↗About this model
The Schwarzschild solution: no rotation or electric charge. The glowing ring is an explanatory illustration, not an image prediction. It is not the size of an observed black hole shadow.
Black hole radius: common questions
Would a black hole with the Sun’s mass pull Earth in?
At Earth’s distance it would have the same gravitational pull as the Sun, neglecting other differences. Earth’s orbit would not suddenly collapse.
Is the bright ring the event horizon?
No. Glowing material and bent light can appear around a black hole; the horizon itself does not emit light that escapes.
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