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Photon Sphere & ISCO 3D Explorer vs alternatives
Photon Sphere & ISCO 3D Explorer computes and animates all four Kerr orbit radii live as you change spin in one 3D scene - a physics textbook diagram wins as a fixed printed reference; the Black Hole 3D Explorer wins for the artistic accretion-disk-glow view with real supermassive-black-hole mass figures.
| Option | Strength | Access | Trade-off |
|---|---|---|---|
| Photon Sphere & ISCO 3D Explorer | Live Kerr-formula radii, spin slider, prograde/retrograde comparison | Free, in-browser, no account | Idealized vacuum solution, not a numerical-relativity simulation |
| Physics textbook diagram | Fixed printed reference, full derivation | Requires the book | No interactivity, one spin value only |
| Black Hole 3D Explorer (this site) | Artistic accretion-disk glow, real Sgr A*/M87* masses | Free, in-browser | No spin parameter, no photon-sphere/ISCO geometry |
Key published figures
| Figure | Value |
|---|---|
| Photon sphere, Schwarzschild | 1.5 Rs = 3M |
| ISCO, Schwarzschild | 3 Rs = 6M |
| ISCO at Thorne limit (prograde) | ~=1.237M |
| Ergosphere, equator | 2M (any spin) |
Start with the step-by-step guide or when to use. Open the Photon Sphere & ISCO 3D Explorer.
FreetoolOnline editorial team
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