SortStack #1072 — 2029-05-16

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 bottlenose dolphin 60 km/h

   Dolphins sleep with half their brain at a time, keeping one eye open to breathe and watch for danger.

3. A charging lion 83 km/h

   Lions are the only big cats that live in groups, and a male's roar can be heard up to eight kilometres away.

4. An arrow loosed from a bow 230 km/h

   A modern compound bow uses pulleys to store huge energy, launching an arrow with deadly accuracy.

5. A bullet from an AK-47 2.7K km/h

   The AK-47 is the most widely produced firearm in history, prized for working even when caked in mud and sand.

6. The X-15 rocket plane 7.3K km/h

   The X-15 flew to the edge of space, and several of its pilots earned astronaut wings without leaving a runway.

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