Convert Megayears to Julian Years
Convert Megayears (Ma) to Julian Years (a_J) instantly and accurately.
Conversion Formula
a_J = Ma × 999979.4661
About Megayears
A megayear (1 Ma) = 10⁶ yr ≈ 3.156 × 10¹³ s - the timescale of geology and tectonic evolution. The K-Pg mass extinction at 66.0 Ma; Cambrian explosion ~538.8 Ma; Great Oxygenation Event ~2,400 Ma. Plate motion at 2-10 cm/yr = 200-1,000 km per Ma (Atlantic ~3,000 km wider since Pangaea rifting ~200 Ma ago). Background extinction rate measured in extinctions per million species-years. 1 Ma = 10⁶ 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
| Megayears (Ma) | Julian Years (a_J) |
|---|---|
| 1 Ma | 999979 a_J |
| 2 Ma | 1999960 a_J |
| 5 Ma | 4999900 a_J |
| 10 Ma | 9999790 a_J |
| 25 Ma | 24999500 a_J |
| 50 Ma | 49999000 a_J |
| 100 Ma | 99997900 a_J |