### Models of Lunar Origin
How Earth's Moon formed remains a topic of scientific investigation. Three models have been proposed:
* Fission Model: Early Earth spun so rapidly that a large mass of material broke away from the mantle to form the Moon. Because the Moon split directly from Earth's outer layers, this model predicts that the Moon's overall chemical composition is virtually identical to Earth's mantle.
* Capture Model: The Moon formed independently in another region of the solar system. As it passed near Earth, it was pulled into a stable orbit by Earth's gravity. This model predicts that the Moon's chemical composition and isotopic ratios are significantly different from Earth's.
* Giant Impact Hypothesis: A Mars-sized planetesimal collided with the young Earth. The intense heat of the collision vaporized volatile elements (elements that easily evaporate, such as water and sodium). The remaining debris orbited Earth and eventually coalesced to form the Moon. This model predicts the Moon has a chemical composition similar to Earth's mantle but is highly depleted in volatile elements.
Based on these models, match each chemical prediction on the left with the correct lunar formation model on the right.
- The Moon will have a chemical composition that is significantly different from Earth's mantle.Capture Model
- The Moon's volatile elements will be depleted compared to Earth's mantle due to vaporization from intense heat.Giant Impact Hypothesis
- The Moon's chemical composition will be nearly identical to Earth's mantle, with no depletion of volatile elements.Fission Model