Archive · 21 Nov 2025
Moon's Origin: Theia Impact Theory Supported by New Study
Scientists found more evidence that a big crash with a Mars-sized object called Theia made our moon.
Theia and Earth were made of similar stuff, so they probably came from the same part of space.
This helps explain some weird things about Earth's insides.
But we still don't know everything about how the moon was made.
Earth's moon likely formed from an impact with a Mars-sized body called Theia
New study finds chemical evidence supporting Theia's role in moon's creation
Theia and early Earth had similar chemical compositions, suggesting they formed in the same part of the solar system
Theia's impact explains Earth's mantle iron content and solar-like enrichment
Despite progress, many questions about Theia and the moon's formation remain unanswered
- Who
- Earth and Theia (a Mars-sized object)
- What
- Collided, forming the moon
- When
- Not long after Earth formed
- Where
- In the inner solar system
- Why
- To explain the moon's origin and Earth's unique chemical composition
Theia Impact Theory
Alternative Hypotheses
Moon's Chemical Similarity to Earth
Theia Impact Theory
Supports Theia impact theory
Alternative Hypotheses
Could be explained by other processes or objects
Origin of Earth's Mantle Iron
Theia Impact Theory
Attributed to Theia by new study
Alternative Hypotheses
Could have other explanations, like late veneer or core formation
- Theia's size
- Roughly the size of Mars
- Moon's formation
- Result of Theia impacting Earth
- Chemical similarity
- Earth, Theia, and moon rocks have similar compositions
- Earth's mantle iron
- Likely came from Theia
- Solar enrichment
- Also likely came from Theia
