This document proposes the Mars Migration Theory, which hypothesizes that Mars originally orbited closer to the Sun at 84 million km before migrating outward to its current distance of 227.9 million km. It suggests Mars' migration caused it to collide with Venus and Earth, creating debris that formed the Earth's moon and Mars' moons. It also addresses questions about the lunar magma ocean and why Venus lacks a moon. The document provides supporting evidence from the order of planets, results of Mars' proposed migration, and proportional relationships between the motion parameters of Mars and Mercury.