Which Moon formation model states that Earth and Moon formed during the same period of time from the same accretion material?

Which Moon formation model states that Earth and Moon formed during the same period of time from the same accretion material?

• A. The Fission model
• B. The Capture model
• C. The Double-Impact model
• D. The Giant-Impact model

Answer: (C)

This question tests how a Moon could form from the same material that built Earth, essentially forming alongside Earth from a shared pool of building blocks. The Double-Impact model envisions two significant collisions during early Earth’s growth that together churned out a disk of debris. This debris comes from material in the same neighborhood as Earth—the same accretion material—so the Moon that forms from that disk is made of essentially the same stuff and on a similar timescale as Earth’s formation. This helps explain why the Moon’s chemical and isotopic fingerprints closely resemble Earth’s and why its origin is tied to Earth’s early assembly rather than a much later capture or a solely external origin. Other scenarios don’t fit this same-origin, same-time idea as neatly. A fission model would eject the Moon from Earth’s spin; a capture model would have the Moon form elsewhere and be only later captured by Earth; a single giant-impact model involves debris from a separate impactor, not the same reservoir of material that built Earth. The Double-Impact picture best accounts for the Moon and Earth sharing a common source material and forming within a related timeframe.

This question tests how a Moon could form from the same material that built Earth, essentially forming alongside Earth from a shared pool of building blocks. The Double-Impact model envisions two significant collisions during early Earth’s growth that together churned out a disk of debris. This debris comes from material in the same neighborhood as Earth—the same accretion material—so the Moon that forms from that disk is made of essentially the same stuff and on a similar timescale as Earth’s formation. This helps explain why the Moon’s chemical and isotopic fingerprints closely resemble Earth’s and why its origin is tied to Earth’s early assembly rather than a much later capture or a solely external origin.

Other scenarios don’t fit this same-origin, same-time idea as neatly. A fission model would eject the Moon from Earth’s spin; a capture model would have the Moon form elsewhere and be only later captured by Earth; a single giant-impact model involves debris from a separate impactor, not the same reservoir of material that built Earth. The Double-Impact picture best accounts for the Moon and Earth sharing a common source material and forming within a related timeframe.