‘4.5-billion-years ago’: Earth collision with Theia produced billions of moons that revolved around our planet once upon a time 

Produced by: Tarun Mishra Designed by: Manoj Kumar

Formation of the Earth-Moon System

The Earth-Moon system originated from a collision with a protoplanet named Theia about 4.5 billion years ago when Earth was just 100 million years old. This impact ejected debris that formed the Moon and some of it returned to Earth.

New Study Proposes Multiple Moons

Scientists at the University of Nevada suggest that the aftermath of the Theia collision likely resulted in the creation of several moons, not just one. These findings are detailed in a study available on the arXiv preprint server.

Circumbinary Particles

The study indicates that these additional moons were circumbinary particles, also known as polar moons, which existed only for a brief period due to their close proximity to Earth.

Initial Proximity of the Moon

At the time of their formation, these moons were much closer to Earth. Initially, the Moon was only about 5% of its current average distance of 238,900 miles from Earth.

Orbital Dynamics

The study explains that polar orbits were stable immediately after the Moon’s formation due to the large amount of debris around the system. These orbits were influenced by nodal precession and Kozai-Lidov oscillations.

Nodal Precession and Kozai-Lidov Oscillations

Nodal precession causes a slow change in a body’s orbital parameters around the angular moment vector. Kozai-Lidov oscillations involve perturbations in a binary system introduced by a distant third body. These factors made polar region particles the most stable.

Tidal Forces and Moon’s Movement

Over time, the Moon began moving away from Earth due to tidal forces. The initial close distance and subsequent movement had significant effects on the stability of these early moons.

Impact on Earth-Moon Binary Eccentricity

If a substantial mass of material ended up in polar or librating orbits, it could have increased the eccentricity of the Earth-Moon binary due to interactions with this debris.

Implications for Exoplanet Studies

The latest theory could help scientists understand more about exoplanets and their formation processes, offering insights into planetary systems outside our solar system.