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Black Holes, drawn

generatorPut in a mass

Every property of a black hole that does not spin is a function of one number. Slide the mass from the Planck mass to the heaviest quasar and read them off, each with the formula that made it.

QuantityFormulaValue

Constants: G = 6.6743 × 10⁻¹¹, c = 299 792 458, ħ = 1.0546 × 10⁻³⁴, k_B = 1.3806 × 10⁻²³, M☉ = 1.989 × 10³⁰ kg. The evaporation time is Hawking's leading form; Page's 1976 count of the particles a hole can emit shortens it by a factor of about three for small holes. The 10 g line is where a person begins to be pulled apart; a tenth of that is felt.

The ladder of masses, from the smallest black hole physics can name to among the heaviest found, with the horizon each makes.
The ladder of masses, from the smallest black hole physics can name to among the heaviest found, with the horizon each makes. · SVG · computed here · Nan · hongdam.net · CC BY 4.0
The stretch across a 1.8 m body at the horizon, by mass. Small holes shred you far outside; a supermassive one lets you cross without noticing.
The stretch across a 1.8 m body at the horizon, by mass. Small holes shred you far outside; a supermassive one lets you cross without noticing. · SVG · computed here · Nan · hongdam.net · CC BY 4.0

Time near the horizon

A clock held still at radius r runs slow by √(1 − 2M/r) compared with one far away. Near the horizon that factor goes to zero: hover close enough and the far universe runs its whole future in your afternoon. Falling in, you notice none of this; the slowness is in the comparison, not the clock.

far away
at r