SortStack #78 — 2026-08-26

By speed · Order from slowest to fastest.

1. 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.

2. 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.

3. A migrating monarch butterfly 8 km/h

   Monarchs migrate thousands of kilometres to the same forests their great-grandparents left, guided by instinct alone.

4. An electric scooter 25 km/h

   Shared e-scooters exploded across cities in just a few years, becoming a common sight on sidewalks worldwide.

5. 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.

6. NASA's Parker Solar Probe 692K km/h

   The fastest human-made object ever, it slingshots around the Sun, dipping into the star's blazing outer atmosphere.

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