Convert Sidereal Days to Gigayears
Convert Sidereal Days (sid.d) to Gigayears (Ga) instantly and accurately.
Conversion Formula
Ga = sid.d × 2.730431333e-12
About Sidereal Days
A sidereal day = Earth's rotation period relative to the stars = 23 h 56 min 4.0905 s = 86,164.0905 s - ~3 min 56 s shorter than the 24 h solar day because Earth advances ~1° in its orbit each day. Equatorial telescope mounts rotate at one turn per sidereal day to track stars. VLBI, GPS orbit determination, and polar-motion monitoring use sidereal rotation as their reference. 1 sid. day = 86,164.0905 s.
About Gigayears
A gigayear (1 Ga) = 10⁹ yr ≈ 3.156 × 10¹⁶ s - the timescale of stellar evolution and cosmology. Universe age: 13.787 ± 0.020 Ga (Planck CMB). Sun: 4.603 Ga old; red giant in ~5 Ga. A 0.1 M☉ red dwarf lives ~10,000 Ga. Uranium-238 half-life = 4.468 Ga (used in radiometric dating). Proton decay (GUT prediction): ~10³⁴ yr = ~10²⁵ Ga. 1 Ga = 10⁹ yr.
Quick Reference Table
| Sidereal Days (sid.d) | Gigayears (Ga) |
|---|---|
| 1 sid.d | 2.73 × 10-12 Ga |
| 2 sid.d | 5.461 × 10-12 Ga |
| 5 sid.d | 1.365 × 10-11 Ga |
| 10 sid.d | 2.73 × 10-11 Ga |
| 25 sid.d | 6.826 × 10-11 Ga |
| 50 sid.d | 1.365 × 10-10 Ga |
| 100 sid.d | 2.73 × 10-10 Ga |