The Moon’s Violent Origin

Records of our planet’s creation have largely been erased, due to a continual reshaping of its surface through geological action. But the Moon has remained essentially dormant, and as such,

 its heavily pitted surface preserves solar system events going back billions of years. The Moon therefore also provides a window into planet earth’s primordial history.

The Apollo program’s main goal was to distinguish among the leading theories at the time, about how the Moon was actually formed. One theory suggested that the Moon formed independently from Earth, and was later caught by our planet during a fortuitous close flyby.

MOON RIPPED AWAY FROM EARTH’S BLOATED BELLY:

The co-formation theory, In contrast with this theory, there is another one referred to,  as the co-formation theory which envisions that the Moon grew alongside Earth, the pair of which, accumulated mass from the same material source. A third theoretic model is that of fission, in which it is proposed that ancient Earth had at one time, rotated so rapidly that it became unstable, which resulted in it developing a bloated midsection and finally shed the material from its equator which eventually became the Moon.

THE MOON COULD BE AS OLD AS ALL THE STARS:

Apollo’s cache of The lunar samples and data brought back by the Apollo spacecraft introduced researchers to some tantalizing new clues as well as certain constraints for these three models. For example, when measuring the age of the oldest Apollo samples, they showed that the Moon must have formed around 4.5 billion years ago, which is only 60 million years or so after the first grains in our solar system had condensed. This means that our Moon came into existence in the same early epoch that saw the birth of all the planets.

THE MOON IS ONLY 30% OF EARTH’S TOTAL MASS:

 The Giant Impact Hypothesis, suggests that a large Mars-sized impactor referred to as Theia had slammed into Earth, which created an orbiting disk of debris that eventually coagulated into the Moon. In measurements of the Moon’s mass and radius, when remotely measured, researchers now also know its density is anomalously low, which indicates a lack of iron. In contrast, 30 percent of Earth’s mass is trapped in its iron-rich core, while the Moon’s core accounts for barely a few percent of its total mass.

Despite this substantial difference in iron, Apollo samples later revealed that mantle rocks from the Moon and Earth have remarkably similar oxygen concentrations. Lunar and terrestrial rocks differ significantly from meteorites originating from Mars or from other stars and planets in the asteroid belt, which shows that Earth and the Moon’s mantle share a past connection.

When compared with Earth, lunar rocks are also more depleted in so-called volatile elements — which are those that vaporize easily upon heating — this indicates that the Moon was formed at extremely high temperatures.

Our researchers also know that our tidal interactions had forced the Moon to spiral outward over time, resulting in Earth spinning more slowly.

Finally, precise measurements of the Moon’s position are obtained using surface reflectors which were placed on the moon during the Apollo program. These have subsequently verified that the Moon’s orbit expands by about 1.5 inches or (3.8 centimeters) each year.

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