Convert Sidereal Years to Seconds
Convert Sidereal Years (a_sid) to Seconds (s) instantly and accurately.
Conversion Formula
s = a_sid × 31558149.76
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 Seconds
The second (s) is the SI base unit of time, defined since 1967 as exactly 9,192,631,770 periods of the caesium-133 ground-state hyperfine transition at 0 K. Caesium fountain clocks realise this to ~10⁻¹⁶ (1 s lost per ~300 million years); optical lattice clocks (Sr, Yb) reach ~10⁻¹⁸. The second links to the metre via the defined speed of light c = 299,792,458 m/s exactly. 1 s = 1,000 ms = 1/60 min.
Quick Reference Table
| Sidereal Years (a_sid) | Seconds (s) |
|---|---|
| 1 a_sid | 31558100 s |
| 2 a_sid | 63116300 s |
| 5 a_sid | 157791000 s |
| 10 a_sid | 315581000 s |
| 25 a_sid | 788954000 s |
| 50 a_sid | 1.578 × 109 s |
| 100 a_sid | 3.156 × 109 s |