SortStack #3333 — 2035-07-25

By speed · Order from slowest to fastest.

1. The creep of a mountain glacier 175320 mm/year

   Glaciers flow downhill under their own weight like very slow rivers of ice, grinding valleys as they go.

2. A king penguin waddling on land 2.8 km/h

   A penguin's waddle is surprisingly efficient, storing and releasing energy with each side-to-side rock.

3. A running pig 17 km/h

   Pigs are smarter than dogs by many measures, able to learn their names and even play simple video games.

4. A record tennis serve 270 km/h

   The fastest serves leave the racket so quickly the returner must react before the ball has even crossed the net.

5. A peregrine falcon in a dive 410 km/h

   The peregrine is the fastest animal on Earth, diving so fast it has baffles in its nostrils to breathe.

6. A 5.56mm rifle bullet 3.1K km/h

   Small, fast rifle rounds tumble on impact, transferring energy in ways a slower, heavier bullet would not.

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