How was the moon formed ? Hit and run, or one of the biggest impacts?

Our moon is an anomaly is more than one ways, firstly its the only moon with the dullest name just as Earth is Earth the moon of Earth is called Moon, even the Kerbles were creative with calling their the Mun!

Secondly its one of the only satellites bodies currently theorised to have originated from the body it orbits, unlike other moons which are either captured or produce from ancient ring systems.

However, the actual formation of the moon is still in debate with scientific research on the subject bringing published in science this week.

It is generally accepted that the formation of the moon and the spin on the Earth on its axis are linked and that it was an impact between two bodies, a larger Earth and the Mars-size Theia that produced both these phenomena,

The impact between the two planets caused major disruptions of both bodies and flung debris from the collision into an orbit around the crippled planet. Over time the debris comes together and forms the moon and the initial collision disrupts the rotation of the Earth so that it moves are a slower rate the previously.

There have been links between the Earth and the moon ever since Apollo astronauts brought back samples of Moon rock to analyses. The composition of the moon is similar to that predicted of a Young Earth. since the formation of the moon, the Earth dynamic internal heating has changed and evolved the planet’s crust through millennial of plate tectonics. Whereas the moon becomes dormant and still.

A second and most important of the evidence for the Earth and Moon originating from on body is the oxygen isotope composition.

Oxygen isotopes are used as a characterization for the different planetary bodies of the Solar System. Each meteorite family, asteroid and planet has a singular oxygen isotope composition with a few overlaps. It is this which allows scientists to discover the original of Martian and Lunar Meteorites and group other meteorites into logical families.


The oxygen isotope composition of the rock brought back from the Moon sits on what in the trade is known as the Terrestrial Fractionation Line. This TFL is the line on which all rocks from Earth fall, along with the lunar samples suggesting that the Moon and the Earth originate from the same or similar body.

However this is the crux of the matter, Earth and Moon rocks are similar but my own experiments have shown the impressive survivability of the smaller objects during an impact. Therefore the question is: Where is the material from Theia?

Recent work investigating the oxygen isotope composition of Lunar Rocks suggest that the Moon and Earth have near identical Theia contents due to their indistinguishable oxygen isotope composition meaning that the moon-forming impact thoroughly mixed and homogenized the oxygen isotopes of Theia and the early Earth (Proto-earth).

Therefore there was no Hit and run collision but a high energy, high – angular -momentum impact that mixed the material of Theia with he Proto Earth distributing it homogeneously in the newly formed Moon and Earth.