Convert Square Megameters to Barns
Convert Square Megameters (Mm²) to Barns (b) instantly and accurately.
Conversion Formula
b = Mm² × 1.000000000e+40
About Square Megameters
A square megameter (Mm²) equals the area of a square with sides of one million meters - 10¹² m², or one trillion square meters. At this scale we describe major geographic and planetary regions. The entire land surface of Earth is about 149 Mm², the Indian Ocean covers roughly 70 Mm², and the Sahara Desert spans approximately 9.2 Mm². Square megameters provide a convenient scale for comparing continent-sized areas without resorting to hundreds of millions of square kilometers.
About Barns
A barn (b) is a unit of area used in nuclear and particle physics to measure effective cross-sections of atomic nuclei and particle interaction probabilities. Equal to 10⁻²⁸ m² (10⁻²⁴ cm²), it was humorously named during the Manhattan Project - physicists joked that uranium nuclei were 'as big as a barn' at the subatomic scale. Particle physics experiments at accelerators like CERN report cross-sections in millibarns (mb), microbarns (μb), nanobarns (nb), and femtobarns (fb).
Quick Reference Table
| Square Megameters (Mm²) | Barns (b) |
|---|---|
| 1 Mm² | 1 × 1040 b |
| 2 Mm² | 2 × 1040 b |
| 5 Mm² | 5 × 1040 b |
| 10 Mm² | 1 × 1041 b |
| 25 Mm² | 2.5 × 1041 b |
| 50 Mm² | 5 × 1041 b |
| 100 Mm² | 1 × 1042 b |