What is the average diameter of the moon?

The Moon’s average diameter is around 3,474 kilometers, a quarter of the Earth’s 12,742 km. This size makes the Moon the fifth largest natural satellite in the solar system, and the largest satellite in proportion to the planet it orbits.

Although the Moon is much smaller than the Earth, its diameter is sufficient for it to exert a major influence on our planet, notably through tides and the stabilization of the Earth’s axis. By way of comparison, the solar system’s largest satellite, Ganymede (moon of Jupiter), has a diameter of 5,268 km, while Titan (moon of Saturn) measures 5,151 km.

The Moon is considered a relatively large satellite compared to some dwarf planets such as Pluto, whose diameter is 2,377 km, meaning that the Moon is even larger than some planetary objects in the Solar System.

Although the Moon’s average diameter is 3,474 km, there are minor variations due to its slightly flattened shape. Unlike the Earth, which is an oblate spheroid, the Moon has a more irregular shape. Its equatorial diameter is 3,476 km, slightly larger than its polar diameter of 3,472 km.

The Moon formed around 4.5 billion years ago, probably as a result of a giant impact between the young Earth and an object the size of Mars, often referred to as Theia. Following this collision, fragments of matter coalesced to form the Moon, which gradually cooled and stabilized its orbit.

The Moon’s size has remained virtually unchanged since its formation, although it is slowly moving away from the Earth at a rate of around 3.8 cm per year. In the very long term, this could influence its gravitational effect on our planet.

The Moon’s diameter plays a key role in many terrestrial phenomena. Its size, combined with its average distance of 384,400 km, is the cause of total solar eclipses. Indeed, while the Moon is 400 times smaller than the Sun, it is also 400 times closer to the Earth, enabling it to completely obscure our star as it passes in front of it.

What’s more, thanks to its size and mass (7.35 × 10²² kg), the Moon generates enough gravitational force to cause ocean tides, thus influencing the Earth’s marine ecosystems and climate.

If we compare the Moon with other celestial bodies, we see that it is larger than Pluto or some of the Solar System’s minor satellites, but much smaller than the large moons of Jupiter and Saturn.

However, because of its proximity to the Earth and its importance in the development of life and climate, it remains one of the most studied celestial objects in astronomy.

The Moon’s diameter is 3,474 km, making it a relatively large satellite compared to the Earth. Its gravitational influence and stable presence have had a major impact on the history and evolution of our planet. Thanks to space missions and astronomical observations, we continue to explore and better understand this fascinating celestial body, which remains the only star visited by man outside the Earth.

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