Convert Gigayears to Millennia
Convert Gigayears (Ga) to Millennia (ka) instantly and accurately.
Conversion Formula
ka = Ga × 1000000
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 Millennia
A millennium (1 ka) = 1,000 Gregorian years ≈ 3.156 × 10¹⁰ s. Standard unit in archaeology and Quaternary geology: Neolithic transition ~10-12 ka BP; Last Glacial Maximum ~21 ka BP; Homo sapiens leaving Africa ~60-70 ka BP. Milankovitch cycles include the 41 ka obliquity and ~100 ka eccentricity cycle. EPICA Antarctic ice core spans ~800 ka. Precession completes ~26 ka. 1 ka = 1,000 yr.
Quick Reference Table
| Gigayears (Ga) | Millennia (ka) |
|---|---|
| 1 Ga | 1000000 ka |
| 2 Ga | 2000000 ka |
| 5 Ga | 5000000 ka |
| 10 Ga | 10000000 ka |
| 25 Ga | 25000000 ka |
| 50 Ga | 50000000 ka |
| 100 Ga | 100000000 ka |