Convert Shakes to Fortnights

Convert Shakes (sh) to Fortnights (fn) instantly and accurately.

Shakes (sh)
Fortnights (fn)

Conversion Formula

fn = sh × 8.267195767e-15

About Shakes

A shake = exactly 10 ns (10⁻⁸ s) - the informal unit for fission prompt-neutron generation time, coined at Los Alamos during the Manhattan Project (1943-1945). A prompt-neutron generation in a supercritical core takes ~1-10 shakes; a full explosive chain reaction unfolds over ~50-100 shakes. The name alludes to 'two shakes of a lamb's tail'. Still used in reactor physics and weapons-design calculations. 1 shake = 10 ns.

About Fortnights

A fortnight = exactly 14 days = 2 weeks = 1,209,600 s. From Old English 'feowertiene niht' (fourteen nights), reflecting the Germanic custom of counting nights. Common in British, Irish, Australian, and NZ English for pay periods, rental cycles, and parliamentary recesses. The Moon's phase advances ~half a synodic month (≤14.77 days) per fortnight; spring and neap tides also cycle fortnightly. 1 fortnight = 14 d = 1,209,600 s.

Quick Reference Table

Shakes (sh)Fortnights (fn)
1 sh8.267 × 10-15 fn
2 sh1.653 × 10-14 fn
5 sh4.134 × 10-14 fn
10 sh8.267 × 10-14 fn
25 sh2.067 × 10-13 fn
50 sh4.134 × 10-13 fn
100 sh8.267 × 10-13 fn

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