The Moon May Have Formed Inside The Earth When It Was Just A Vaporized Rock (Study)

Artist's rendering of the moon crashing in a proto-Earth.

The moon may have formed inside the Earth when our planet was just a swirling cloud of vaporized rock.

According to a new study conducted by researchers from the University of California- Davis and Harvard University, the moon might have sprung into existence from a spinning cloud of vaporized rock from Earth.

While previous theories suggest that the moon was formed after an astronomical body collided with Earth 4.5 billion years ago, the new model claims that the natural satellite formed inside our planet when it was just a spinning cloud of vaporized rock. The collision threw tons of molten rock and metal in Earth’s orbit, this matter eventually forming the moon.

The researchers explained that the moon was formed from a planetary object called synestia.

A synestia occurs when young, planet-sized objects collide with one another, creating a rapidly spinning mass of molten and vaporized rock. This volatile cloud orbits around itself and it is said to resemble a gigantic donut floating in space. According to the researchers, a synestia can last no more than 100 to 200 years, as it gradually shrinks and loses heat.

“The Moon forms inside the vaporized Earth at temperatures of four to six thousand degrees Fahrenheit and pressures of tens of atmospheres,” says Simon Lock, a graduate student at Harvard.

According to Lock, after the Earth-synestia formed, massive chunks of molten rock injected into orbit during the impact formed the seed for the Moon. Then, vaporized silicate rock condensed at the surface of the synestia and sprinkled itself onto the would-be moon. The process added to the rocks’s mass while the Earth-synestia gradually shrank.

The new theory directly contradicts the prevailing hypotheses of the moon’s origin, in which a Mars-sized object called Theia crashed into a proto-version of Earth 4.5 billion years ago.

The moon’s chemical composition is very similar to that of our planet, which suggests that it was made from the same material. This theory, called the Big Splash, showed that 9.2 million years ago after the Big Bang, a protoplanetary disk was formed, which was followed by planet collisions that merged to form bigger celestial bodies. Once Theia collided with Earth, the debris from the impact would have created two moons orbiting the young planet. These two moons eventually collided and the smaller moon was destroyed.

The study was published in the Journal of Geophysical Research: Planets.

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