SortStack #2157 — 2032-05-05

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 drift of a tectonic plate 21.9 mm/year

   Plates move about as fast as your fingernails grow, yet over millions of years they have rearranged whole continents.

3. A chicken foraging 3.6 km/h

   Chickens can recognise over a hundred individual faces, both other birds and the humans who feed them.

4. A scurrying hedgehog 6.4 km/h

   A startled hedgehog rolls into a tight ball, raising up to 6,000 spines that few predators dare to bite.

5. 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.

6. The International Space Station in orbit 28K km/h

   The station circles Earth so fast its crew sees about 16 sunrises and sunsets every single day.

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