2025/02/26 by Liu, Wenshuai
#Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2502.18837
According to the giant impact theory, the Moon formed through accreting the debris disk produced by a collision between Theia and the proto-Earth, and the predicted lunar orbital inclination relative to the Earth's equatorial plane is about within one degree when Moon formed. However, the current lunar orbital inclination requires the Moon's orbital inclination relative to the Earth's equator to be about ten degrees when traced back to the time of lunar formation. We show that, after explaining Earth-Moon isotopic similarity in the framework of the canonical giant impact theory, gravitational tidal interaction between Earth and the two moons with negligible orbital inclination could lead to the merger of the two moons with newly formed moon's orbital inclination relative to Earth's equator exceeding 10 degrees.