Age of earliest swords

Age of earliest swords (3,700 y)

/fact/age-of-earliest-swords

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Neat Ratios ...

Age of earliest swords (3,700 y)

is 1/4 of Time since first humans in Americas (15,000 y)...more
is 2 x Time since the birth of Diophantus (1,814 y)...more
is 50 x Period of Halley's Comet's orbit (75.3 y)...more
is 250 x Time since first iPhone launched (15 y)...more
is 250 x Lifespan of a cat (15 y)...more
is 2000 x Period of Mars's orbit (1.88 y)...more

If this was a standard unit ...