Convert Microcenturies to Sidereal Years
Convert Microcenturies (µcy) to Sidereal Years (a_sid) instantly and accurately.
Conversion Formula
a_sid = µcy × 9.999825794e-5
About Microcenturies
A microcentury (µcy) = 10⁻⁶ of a Julian century = 3,155.76 s ≈ 52 min 35.76 s. Popularised by Richard Feynman, who told audiences a one-hour lecture was 'approximately one microcentury'. An 87-minute film ≈ 1.65 microcenturies. No formal SI recognition, but a favourite pedagogical example of SI prefixes applied to large bases. 1 µcy = 3,155.76 s = 52.596 min.
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
| Microcenturies (µcy) | Sidereal Years (a_sid) |
|---|---|
| 1 µcy | 10 × 10-5 a_sid |
| 2 µcy | 0.000199997 a_sid |
| 5 µcy | 0.000499991 a_sid |
| 10 µcy | 0.000999983 a_sid |
| 25 µcy | 0.00249996 a_sid |
| 50 µcy | 0.00499991 a_sid |
| 100 µcy | 0.00999983 a_sid |