The Year is 20X9...

Metroid Prime 4 takes place in "Cosmic Year 20X9".

This might seem like a simple reference to old games refusing to give a proper date, unless we assume that the Federation uses base twelve and "X" is actually dec, the numeral for 10.

So the year "20X9" would be 3585 in base-10, giving Metroid a reasonable far-off future year even outside of its separate calendar. So Metroid Prime 4's AD year may be 3585.

This would also mean that if the Federation was founded in CY 2000, it was founded in AD 3456, meaning it's over a century old by the time the Metroid games take place.

But that's just a theory.

A Game Theory! 🙂🔫