Convert Gigayears to Julian Years
Convert Gigayears (Ga) to Julian Years (a_J) instantly and accurately.
Conversion Formula
a_J = Ga × 999979466.1
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.
About Julian Years
The Julian year (a_J) = exactly 365.25 days = 31,557,600 s - the IAU standard year for astronomical distances. The light-year is formally 1 ly = c × 1 a_J = 9.461 × 10¹⁵ m (IAU 2012 B2). Julian years differ from Gregorian years by only 648 s (~10.8 min/year); important for high-precision astrometry or calculations spanning centuries. 1 a_J = 365.25 d = 31,557,600 s.
Quick Reference Table
| Gigayears (Ga) | Julian Years (a_J) |
|---|---|
| 1 Ga | 999979000 a_J |
| 2 Ga | 2 × 109 a_J |
| 5 Ga | 5 × 109 a_J |
| 10 Ga | 10 × 109 a_J |
| 25 Ga | 2.5 × 1010 a_J |
| 50 Ga | 5 × 1010 a_J |
| 100 Ga | 10 × 1010 a_J |