Where does the moon originate?

The moon is considered a mystical symbol by many cultures, and many stories have been told about the poetic beauty, magic and power of this planet.

The Moon is the largest satellite and has the closest relationship with the Earth. To date, 12 people have set foot on the Moon to learn about this natural satellite. So how have we learned about the Moon? What is the origin and formation of this planet?

Origin of the Moon

When it comes to how the Moon was created, after thousands of years of research and observation, humanity still has only a loose collection of theories. Let's take a look at widely recognized hypotheses about the origin of the Moon's formation.

The Moon and Earth formed together

This theory posits that the Moon and Earth formed at the same time from a primordial accretion disk—a disk-like flow of gas, plasma, dust, or particles around an astronomical object that gradually collapsed into the interior. in—this would help explain the geological similarities between the two bodies. For example, the Moon's oxygen isotope ratio appears to be identical to Earth's.

Gas from the cloud condenses into matter, and the debris is attracted to attach to this or that object. The Earth happened to absorb more matter and increase its mass. Of the two celestial bodies, the mass of the Earth allowed it to develop a dominant gravitational force and the Moon began to orbit the Earth. However, critics note that this theory does not explain the Moon's current angular momentum around the Earth.

Fission of the Earth created the Moon

In a set of theories about the formation of the early Moon — most notably that of Sir George Darwin, the British astronomer and son of naturalist Charles Darwin — the Earth was is said to have once rotated so fast that clumps of matter flew off its surface. This amount of material is then believed to have condensed into the Moon.

Although the fission theory seemed convincing—since the composition of the Earth's and the Moon's mantles were similar—it failed over time because no one could discover the right combination of properties for a The proto-Earth rotated to create just the right kind of proto-Moon.

More specifically, scientists simply do not believe that the Earth could rotate fast enough to remove pieces of its own material. In addition, to date, astronomical researchers have not found any evidence of such a rapid rotation event on Earth or the Moon.

The Earth 'grabs' the passing Moon in orbit

The third most popular hypothesis is that the Moon could have formed elsewhere in the solar system, but outside the influence of Earth's gravity. Some scientists believe that the Moon may even have been 'captured' by another planet for a time before escaping, and then came close to Earth. The distance is so close that the Earth can attract the Moon into its orbit.

In fact, many planets, such as Mars, are said to have 'captured' small passing asteroids within gravitational range and turned them into their moons. However, scientists have not yet found the mechanism behind how the Earth can 'capture' the Moon to stay in orbit. In addition, this hypothesis also fell out of favor after it was discovered that the Earth and the Moon have similar geological characteristics.

The shattered remains of the planet Theia fuse to form the moon

The theory is based on the violent collision of a Mars-sized planet called Theia with Earth. Scientists assume that Theia is made of other matter, possibly weaker than Earth. After Theia 'attacked', Earth remained relatively intact. However, Theia broke apart and the remaining pieces eventually merged to form the Moon. Although this theory initially sounded convincing, it failed because the Earth and Moon are made of similar elements (especially silicon and oxygen) in similar concentrations.

Where does the moon originate? Picture 1

Theia's impact creates a 'Synestia'

What if Theia struck the early Earth with such force that they both 'evaporated'? Some scientists suggest that a strange bagel-shaped cloud called a synestia may have been created by the collision. They reasoned that this structure could act like a kind of spinning disk, evenly mixing the chemical elements found in each planet. Over time, material outside the synestia coalesced into the Moon, while the remaining material formed the Earth.

The collision of two similar planets

In this scenario, Theia still hits Earth, but complete breakup does not occur and debris from the impact still agglomerates into the Moon. What's unique about this theory is that the matter that makes up Theia is the same matter that makes up the Earth. The question now is: How did Theia form? Perhaps both Theia and Earth formed on opposite sides of the same accretion disk (its material is spread evenly throughout). Then, something disturbed Theia's orbit around the Sun and caused it to drift out of its original position, resulting in Theia crashing into Earth.

Many theories about extraterrestrial impacts

In this theory, the early Earth is believed to have experienced not one but many collisions. Each strike is said to have created a fragment of debris that eventually coalesced into a small moon. Then, these small satellites merged together to form the Moon as it is now.

The hypothesis notes that a disk of material would form within hours of each collision and condense into a small satellite over the course of several hundred years. Israeli scientists proposed the idea in early 2017 and argued that the combined impact of multiple high-speed collisions could produce enough material to form the Moon. However, they also said the mechanism that explains how each of these individual satellites assembles into a larger body has not yet been described.

Lesley Montoya

Update 20 February 2024