moon (satellite)

Article

August 8, 2022

The moon is the only natural satellite of the planet Earth. It is the second brightest object in the Earth's sky after the Sun and the fifth largest satellite of the planets of the Solar System. As of May 1, 2020, the first and only extraterrestrial object of natural origin visited by man. The average distance between the centers of the Earth and the Moon is 384,400 km.

Names

The ancient Romans called the Moon Luna (lat. Luna) from the Indo-European root louksnā - light, glow. Hence the Greek. λύχνος is a lamp. The Greeks called the Earth's satellite Selene (Greek Σελήνη), the ancient Egyptians - Yah (Iach).

In Ukrainian

Planetary characteristics

Radius 1737 km The semi-major axis of the orbit 384,400 km Orbital period 27,321,661 days Eccentricity of the orbit 0.0549 The inclination of the orbit to the equator 5.16 Surface temperature from −190° to +120 °C A day 708 hours Average distance from the Earth 384,400 km (approx. 30 diameters of the Earth; at perigee — 356,400 km, at apogee — 406,800 km) The Moon has attracted the attention of people since prehistoric times. It is the second brightest object in the sky after the Sun. As the Moon orbits the Earth with a period of about a month, the angle between the Earth, the Moon, and the Sun changes; we observe this phenomenon as a cycle of lunar phases. The time period between successive new moons is 29.5 days (709 hours).

Orbit

Since ancient times, people have tried to describe and explain the movement of the moon, using increasingly accurate theories. Brown's theory is the basis of modern calculations. Created at the turn of the 19th and 20th centuries, it explained the movement of the moon with the accuracy of the measuring devices of that time. At the same time, more than 1,400 members (coefficients and arguments for trigonometric functions) were used in the calculation. Modern science can calculate the movement of the moon and verify the calculations in practice with greater accuracy. Thus, expressions with tens of thousands of terms are used to calculate the position of the Moon with the accuracy of laser location measurements, and there is no limit to the number of terms in the expression if even greater accuracy is required. In the first approximation, it can be assumed that the Moon moves in an elliptical orbit with an eccentricity of 0.0549 and a semi-major axis of 384,399 km. The real movement of the Moon is quite complex, for its calculation it is necessary to take into account many factors, in particular the flattening of the Earth and the powerful influence