SortStack #1695 — 2031-01-29

By speed · Order from slowest to fastest.

1. A slowly marching sand dune 20161.8 mm/year

   Wind pushes desert dunes forward grain by grain, swallowing roads and even villages over the decades.

2. A housefly in flight 6.8 km/h

   A housefly tastes with its feet, so it can decide whether something is food the moment it lands on it.

3. A racing greyhound 76 km/h

   Greyhounds reach their top speed in just a few strides and spend much of a sprint completely airborne.

4. A common swift in flight 113 km/h

   Swifts can stay airborne for nearly a year without landing, even sleeping on the wing high above the ground.

5. The SR-71 Blackbird 3.5K km/h

   The Blackbird leaked fuel on the ground because its panels only sealed once heat expanded them in flight.

6. A tank's sabot round 5.8K km/h

   A sabot round sheds a casing in flight, leaving a slim dart of dense metal that punches through armour.

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