Convert Sidereal Years to Centuries
Convert Sidereal Years (a_sid) to Centuries (cent) instantly and accurately.
Conversion Formula
cent = a_sid × 0.01000037956
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.
About Centuries
A century = exactly 100 Gregorian years ≈ 3.156 × 10⁹ s. Standard unit of historical periodisation (the 20th century, the 18th-century Enlightenment). IPCC projects warming and sea-level rise on century timescales. Precession of the equinoxes advances ~1.39°/century, so zodiac constellations no longer match their named seasons. Ice-core and radiocarbon records are commonly displayed at century resolution. 1 century = 100 yr.
Quick Reference Table
| Sidereal Years (a_sid) | Centuries (cent) |
|---|---|
| 1 a_sid | 0.0100004 cent |
| 2 a_sid | 0.0200008 cent |
| 5 a_sid | 0.0500019 cent |
| 10 a_sid | 0.100004 cent |
| 25 a_sid | 0.250009 cent |
| 50 a_sid | 0.500019 cent |
| 100 a_sid | 1.00004 cent |