Convert Shakes to Sidereal Years
Convert Shakes (sh) to Sidereal Years (a_sid) instantly and accurately.
Conversion Formula
a_sid = sh × 3.168753579e-16
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 Sidereal Years
The sidereal year = Earth's orbital period relative to the stars = 365.25636 days = 31,558,149.8 s - about 20 min 24 s longer than the tropical year. The gap arises from precession of the equinoxes (~50 arcsec/year westward drift), which causes the tropical year to end slightly before the sidereal orbit completes. JPL DE440 ephemerides and J2000.0 epoch are anchored to the sidereal frame. 1 a_sid = 365.25636 d.
Quick Reference Table
| Shakes (sh) | Sidereal Years (a_sid) |
|---|---|
| 1 sh | 3.169 × 10-16 a_sid |
| 2 sh | 6.338 × 10-16 a_sid |
| 5 sh | 1.584 × 10-15 a_sid |
| 10 sh | 3.169 × 10-15 a_sid |
| 25 sh | 7.922 × 10-15 a_sid |
| 50 sh | 1.584 × 10-14 a_sid |
| 100 sh | 3.169 × 10-14 a_sid |