3.8 cm

It has been confirmed that the Moon is moving away from the Earth at a rate of about 3.8 cm per year. This is due to changes arising over long periods from the tidal interactions between the Moon and the Earth, and over billions of years the Moon will retreat a considerable distance from the Earth.

Giant Impact hypothesis

Regarding the Moon’s origin, the most widely supported idea today is the Giant Impact hypothesis. According to this hypothesis, the Moon formed as a result of a Mars-sized body colliding with the young Earth. Other proposed ideas include the fission hypothesis, the co-formation (sibling) hypothesis, and the capture hypothesis.

3,474 km

The Moon’s diameter is about 3,474 km. This is roughly one quarter of Earth’s diameter, and considering that Earth’s diameter is about 12,742 km, we can see that it’s quite small.

about 28 days

The period it takes for the Moon to make one orbit around the Earth is about 27.3 days. However, because the Earth is also orbiting the Sun, the synodic period, which represents the phases of the Moon, is about 29.5 days.

gravity

The tides on Earth are caused by the Moon’s gravity. The Moon and Earth attract each other gravitationally, and this pull on seawater produces the tides on Earth. In particular, when the Moon is at its closest point to Earth, the gravitational effect increases, causing larger high (and low) tides. This is called tidal force.

About 380,000 kilometers

The distance between the Moon and the Earth is about 380,000 kilometers. However, since the Moon orbits the Earth in an elliptical path, it is about 406,000 kilometers at its farthest and about 364,000 kilometers at its closest, with an average distance of approximately 380,000 kilometers.

Directly opposite the Sun as seen from Earth

At new moon, the Moon is positioned directly between the Earth and the Sun from our point of view. In other words, the Moon lies in the same direction as the Sun as seen from Earth, and the side of the Moon facing Earth receives no sunlight, making it invisible to us. For reference, the configuration opposite the Sun as seen from Earth occurs at full moon.

crab

In Japan, it’s said that a rabbit is pounding mochi, but in Southern Europe there’s a tradition of describing the moon’s craters as a crab. People have imagined various shapes in the moon’s patterns throughout history.

When the Earth is completely within the Moon’s shadow

A total solar eclipse is an astronomical phenomenon that occurs when, at new moon, the Moon is positioned between the Earth and the Sun and the Earth falls entirely within the Moon’s shadow. At that time, the Moon completely covers the Sun, creating a region called the path of totality where sunlight does not reach the Earth.

1/6

The Moon’s gravity is about one-sixth that of Earth. This means your weight on the lunar surface is roughly one-sixth of your weight on Earth.