For any mass, there's a radius below which space curves so hard that not even light can outrun it — the Schwarzschild radius, rₛ = 2GM/c². Pick a mass. See where the line falls.
01Masslog scale · 52 orders of magnitude
EverydayterrestrialPlanetaryStellarSupermassive
Sun
An average G-type main-sequence star
Mass1.989 × 10³⁰ kg
02Schwarzschild radiusrₛ = 2GM/c²
Event horizon radius
2.95 km
If the Sun collapsed to a black hole, its event horizon would fit inside Manhattan.
Compression ratio: 472,000 × — from its current radius down to its Schwarzschild radius.
rₛ (meters)
2,953 m
rₛ (AU)
1.97 × 10⁻⁸
Schwarzschild area
1.10 × 10⁸ m²
Mean density
1.84 × 10¹⁹ kg/m³
Scale comparison · where rₛ sits on the cosmic ruler
2.95 km
03Black hole propertiesat this mass, if collapsed
Hawking temperature
61.7 nK
Far colder than the cosmic microwave background (2.725 K). The bigger the black hole, the colder it radiates.
T = ℏc³ / (8πGMk₋)
Evaporation time
2.1 × 10⁶⁷ years
Time to fully evaporate via Hawking radiation. The universe is only ~10¹⁰ years old.
t ≈ 5120πG²M³/(ℏc⁴)
Surface gravity at horizon
1.56 × 10¹² g
Acceleration just outside the event horizon. Tidal forces follow the inverse rule: bigger black holes are gentler.
κ = c⁴/(4GM)
Photon sphere
4.43 km
Radius at which light can orbit the black hole in unstable circles. Photons here will eventually fall in or escape.
r = 1.5 rₛ
ISCO · innermost stable orbit
8.86 km
Closest stable circular orbit for matter. Inside ISCO, you spiral in irrevocably — this is the inner edge of an accretion disk.
r = 3 rₛ
Tidal force on 2 m human
3.1 × 10¹² g/m
Difference in gravity between your head and feet at the horizon. Above ~10¹&sup0; g/m, you're spaghettified.