What can meteorites tell us about the Moon's origin?

Meteorites contribute to the debate about how the Moon formed in several ways.

Lunar meteorites. Several hundred lunar meteorites have been found, mainly in hot deserts and Antarctica. They come from random places on the Moon, including the far side and areas never visited. Many are highland breccias rich in feldspar, supporting the idea that the Moon's early crust formed by crystals floating on a global magma ocean. Some lunar meteorites, such as those rich in KREEP, give information about the Moon's late magmas.

Isotopic similarity. The Moon's oxygen isotopes are almost identical to Earth's, while meteorites from Mars, Vesta and other bodies differ. Isotopes of titanium, chromium and tungsten also match closely. In the giant impact hypothesis, a Mars-sized body collided with the early Earth, and the Moon formed from the debris. If most of the Moon came from the impactor, we might expect it to differ from Earth. Meteorites provide the comparison: because different bodies usually have distinct isotopes, the Earth–Moon match is significant. Possible explanations include thorough mixing in an extremely energetic impact, or an impactor that formed close to Earth from similar material.

Enstatite chondrites. These meteorites share isotopes with Earth and the Moon, suggesting that the inner Solar System material that built Earth resembled them.

Timing. Dates from lunar rocks and meteorites suggest the Moon formed roughly 4.4 to 4.5 billion years ago.

Together, meteorites and Apollo samples continue to refine our understanding of the Moon's birth.

More about the science of meteorites

• Why are there no known meteorites from Mercury or Venus?
• What is the most common type of meteorite to fall?
• Do meteorites contain sugars or DNA building blocks?
• How do scientists stop meteorites being contaminated?
• Why are witnessed falls more useful to science than finds?
• What happens to a meteorite as it weathers on Earth?

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