SortStack #792 — 2028-08-09

By speed · Order from slowest to fastest.

1. The growth of a cave stalactite 0.1 mm/year

   Most stalactites lengthen by less than a tenth of a millimetre a year, dripping mineral by mineral over millennia.

2. The growth of human hair 175.3 mm/year

   Scalp hair grows roughly 1.25 centimetres a month, so a single strand reaching your shoulders is years old.

3. A giant tortoise 500 m/h

   Giant tortoises can live over 150 years, ambling through more than a century of slow, steady days.

4. A manatee cruising 4.3 km/h

   Manatees are gentle plant-eaters so buoyant they use their heavy bones as ballast to keep from floating up.

5. A person jogging 10.8 km/h

   Humans are among the best endurance runners on Earth, able to outlast horses over very long distances in heat.

6. A bullet from a .357 Magnum 1.5K km/h

   A supersonic bullet creates a tiny sonic boom, which is part of the sharp crack you hear from a gunshot.

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