New study suggests Moon is made entirely of Earth, not Theia

For years, scientists have believed that the Moon was formed after a massive collision between Earth and a Mars-sized planet called Theia. The prevailing theory suggested that debris from both celestial bodies combined to form the Moon. However, a groundbreaking new study challenges this idea, proposing that the Moon is composed solely of material from Earth.

The Study's Findings

A team of scientists analyzed 14 lunar rock samples alongside similar minerals from Earth. Their focus was on oxygen-17, a rare isotope of oxygen. The results showed an almost identical composition between the Moon and Earth, with no traces of Theia. This suggests that the Moon originated purely from Earth's mantle after the colossal impact, with no significant contribution from Theia's material.

Where is Theia Now?

One theory is that Theia’s impact stripped away its rocky exterior before it merged with Earth, sinking into our planet’s core like a metallic cannonball. This would mean that rather than existing as part of the Moon, Theia might be buried deep inside Earth.

Implications for Earth's Water

Another long-standing theory suggested that Theia brought water to Earth. However, this new study points to asteroids as the more likely source. Scientists found a match between Earth's oxygen-17 levels and those in a specific type of meteorite called enstatite chondrites, indicating that water may have arrived much later, well after the Moon had formed.

What This Means for Science

Theia has fascinated researchers for years, with theories suggesting its role in shaping Earth’s continents and even influencing volcanic activity. While its exact fate remains uncertain, this study reshapes our understanding of how the Moon came to be, reinforcing the idea that it is Earth's distant sibling rather than a mix of two worlds.