The Moon

The Moon

The Moon is the Earth's only natural satellite

Geography

Keywords

Moon, formation of the Moon, satellite, Earth, Solar System, orbit of the Moon, orbital plane, astronomy, orbital period, physical, surface of the Moon, moon phase, moon, geography, physics

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Scenes

Orbit of the Earth

  • Moon
  • Earth
  • Sun
  • the orbit of the Earth
  • orbital period: 365.25 days
  • average distance from the Sun: 149,600,000 km (92,957,101.6 mi)

The Earth is the third planet from the Sun in the Solar System. It is the fifth largest of the planets, and the largest of the terrestrial planets in terms of diameter, mass and density. The Earth is the only known planet in the Universe where life exists. According to our current understanding, the Earth formed
4.57 billion years ago, and life appeared on its surface within a billion years.

While the Earth orbits around the Sun once, it rotates around its axis about 365.25 times. This time period is one year. The orbital velocity of the Earth is 30 km/s (18,64 mi/s).

The tilt of the Earth’s axis is 23.5°. As a result, within one year the angle of incidence of sunlight changes at the same location, and this is the reason why seasons change. Our planet rotates (relative to the Sun) once every 24 hours. Due to the centrifugal force caused by the rotation, the planet is somewhat flattened.

The Earth’s only natural satellite is the Moon, which formed about 4.53 billion years ago. The Moon’s gravity creates tides, which keep the axis of rotation of the Earth at an almost constant angle and slow down the planet’s rotation slightly (the length of one day increases by 0.002 seconds every 100 years).

Orbit of the Moon

  • Earth
  • Moon
  • the orbit of the Moon
  • orbital period: 27.3 days
  • perigee: 363,104 km (225,622.3 mi)
  • apogee: 405,696 km (252,087.73 mi)
  • orbital plane of the Moon
  • orbital plane of the Earth

The Moon was formed not long after the formation of the planets, as a result of the collision of the young Earth and another ancient planet of about the size of Mars. During the collision, a large amount of material was ejected from the Earth’s mantle, which started to orbit the Earth, forming a disk. The material of the disk soon collected into a spherical shape due to gravity, and the Moon was formed. At that time, it was about 20 times closer to the Earth than it is today. The Moon’s diameter is about one-fourth of the Earth’s; it is an extremely large moon in the inner solar system. Compared to its mother planet, the Moon is the largest natural satellite in the Solar System.

While orbiting the Sun, the Earth and the Moon orbit their common center of mass (located below the surface of the Earth). The Moon is in synchronous rotation around the Earth: its axial rotation and orbital period are the same; therefore, we always see the same side. Its orbital period is 27.32 days, while the lunar phase period (from full moon until the next full moon) is 29.53 days.

The Moon has very important effects on the Earth. Without the Moon, many things would have happened differently. The Moon has had a significant influence on evolution as well: tides played a role in drawing life onto dry land from water; our natural satellite also stabilized the Earth’s axial tilt, creating the conditions for the climate to stay relatively constant. The major effect of tides on the Earth is the slowing of our planet’s rotation and therefore a gradual increase in the length of the days. 400 million years ago, one year lasted about 400 days and the length of one day was only 21.8 hours. The high tides caused by the Moon´s gravity have an effect on the Moon as well; as a result, the Moon is slowly moving away from the Earth: its orbit is expanding by 4 cm (1.57 inches) every year.

The Moon

  • Montes Alpes
  • Sea of Showers
  • Sea of Cold
  • Sea of Serenity
  • Sea of Tranquility
  • Sea of Fertility
  • Sea of Crisis
  • Sea of Nectar
  • Sea of Clouds
  • Sea of Moisture
  • Sea of Cleverness
  • Eastern Sea
  • Sea of William Henry Smyth
  • Ocean of Storms
  • Montes Carpatus
  • Montes Jura
  • Montes Caucasus
  • Montes Apenninus
  • Montes Taurus
  • Montes Pyrenaeus
  • Montes Cordillera
  • Plato (crater)
  • Copernicus (crater)
  • Gagarin (crater)
  • Szilárd (crater)
  • Zsigmondy (crater)
  • Highland region on the Moon’s other side
  • Bolyai (crater)
  • Eötvös (crater)
  • Pasteur (crater)

Surface

  • Montes Alpes
  • Sea of Showers
  • Sea of Cold
  • Sea of Serenity
  • Sea of Tranquility
  • Sea of Fertility
  • Sea of Crisis
  • Sea of Nectar
  • Sea of Clouds
  • Sea of Moisture
  • Sea of Cleverness
  • Eastern Sea
  • Sea of William Henry Smyth
  • Ocean of Storms
  • Montes Carpatus
  • Montes Jura
  • Montes Caucasus
  • Montes Apenninus
  • Montes Taurus
  • Montes Pyrenaeus
  • Montes Cordillera
  • Plato (crater)
  • Copernicus (crater)
  • Gagarin (crater)
  • Szilárd (crater)
  • Zsigmondy (crater)
  • Highland region on the Moon’s other side
  • Bolyai (crater)
  • Eötvös (crater)
  • Pasteur (crater)

The Moon is the fifth largest satellite
in the Solar System.
It orbits the Earth at a distance of 384 thousand kilometers (238,606.54 mi). Its diameter is a quarter of the Earth’s. Its mass is only one eighty-first of that of the Earth. Therefore its gravity is weaker. Its surface warms up to 130⁰C (266 °F) during the day, but due to the strong heat radiation, it cools down to -160⁰C (-256 °F) at night.

Its surface is composed mainly of volcanic rocks, covered by a thick layer of debris. We can see darker, lower-lying basins, so-called seas, and lighter, higher plateaus on the Moon.
The basins, with the mountains and
craters ringing them, were created by gigantic meteorite impacts. However, the volcanic rock layer and craters
created by geological processes prove that there also used to be active volcanoes on the moon.

So far the Moon is the only celestial body
apart from the Earth where man has ever set foot. US president John F. Kennedy announced on May 25, 1961 that during the course of that decade man would travel to the Moon and return safely back to Earth.

The first manned mission, Apollo 11, lifted off in July 1969, and on July 21 the first people to set foot on the Moon were Neil Armstrong and Buzz Aldrin. "That's one small step for man, one giant leap for mankind." These were the first words Armstrong spoke as he emerged from the lunar module.

Section

  • mantle - It is 19 km (12 mi) thick on the side facing the Earth and 50-60 km (31-37 mi) thick on the other side. Lunar maria (seas) are made up of basalt, while the highlands are made up of impact breccia rock.
  • mantle - It is divided into two parts: the outer and the inner mantle. The outer mantle is solid, the inner mantle is partly molten. The mantle is 1,200 km (746 mi) thick, it consists mainly of oxygen, silicates, magnesium, iron, calcium and aluminium.
  • Nucleus - It is 450-500 km (280-311 mi) in diameter, the outer core is about 300-350 km (186-217 mi) thick and consists of molten rock, while the inner core (150-160 km – 93-99 mi – in diameter) consists of iron and sulfur.

Animation

  • Montes Alpes
  • Sea of Showers
  • Sea of Cold
  • Sea of Serenity
  • Sea of Tranquility
  • Sea of Fertility
  • Sea of Crisis
  • Sea of Nectar
  • Sea of Clouds
  • Sea of Moisture
  • Sea of Cleverness
  • Eastern Sea
  • Sea of William Henry Smyth
  • Ocean of Storms
  • Montes Carpatus
  • Montes Jura
  • Montes Caucasus
  • Montes Apenninus
  • Montes Taurus
  • Montes Pyrenaeus
  • Montes Cordillera
  • Plato (crater)
  • Copernicus (crater)
  • Gagarin (crater)
  • Szilárd (crater)
  • Zsigmondy (crater)
  • Highland region on the Moon’s other side
  • Bolyai (crater)
  • Eötvös (crater)
  • Pasteur (crater)
  • Earth
  • Moon
  • the orbit of the Moon
  • orbital period: 27.3 days
  • perigee: 363,104 km (225,622.3 mi)
  • apogee: 405,696 km (252,087.73 mi)
  • orbital plane of the Moon
  • orbital plane of the Earth
  • mantle - It is 19 km (12 mi) thick on the side facing the Earth and 50-60 km (31-37 mi) thick on the other side. Lunar maria (seas) are made up of basalt, while the highlands are made up of impact breccia rock.
  • mantle - It is divided into two parts: the outer and the inner mantle. The outer mantle is solid, the inner mantle is partly molten. The mantle is 1,200 km (746 mi) thick, it consists mainly of oxygen, silicates, magnesium, iron, calcium and aluminium.
  • Nucleus - It is 450-500 km (280-311 mi) in diameter, the outer core is about 300-350 km (186-217 mi) thick and consists of molten rock, while the inner core (150-160 km – 93-99 mi – in diameter) consists of iron and sulfur.
  • Earth
  • Sun
  • the orbit of the Earth
  • orbital period: 365.25 days
  • average distance from the Sun: 149,600,000 km (92,957,101.6 mi)

Phases of the Moon

Lunar eclipse

Narration

The Earth is the third planet from the Sun in the Solar System. While the Earth orbits around the Sun once, it rotates around its axis about 365.25 times. This time period is one year. Our planet rotates (relative to the Sun) once every 24 hours.

The Earth’s only natural satellite is the Moon, which formed about 4.53 billion years ago. The Moon was formed not long after the formation of the planets, as a result of the collision of the young Earth and another ancient planet of about the size of Mars. During the collision, a large amount of material was ejected from the Earth’s mantle, which started to orbit the Earth, forming a disk. The material of the disk soon collected into a spherical shape due to gravity, and the Moon was formed. At that time, it was about 20 times closer to the Earth than it is today.

While orbiting the Sun, the Earth and the Moon orbit their common center of mass (located below the surface of the Earth). The Moon is in synchronous rotation around the Earth: its axial rotation and orbital period are the same; therefore, we always see the same side. Its orbital period is 27.32 days, while the lunar phase period (from full moon until the next full moon) is 29.53 days.

The Moon has very important effects on the Earth. Without the Moon, many things would have happened differently. The Moon has had a significant influence on evolution as well: tides played a role in drawing life onto dry land from water; our natural satellite also stabilized the Earth’s axial tilt, creating the conditions for the climate to stay relatively constant. The major effect of tides on the Earth is the slowing of our planet’s rotation and therefore a gradual increase in the length of the days. 400 million years ago, one year lasted about 400 days and the length of one day was only 21.8 hours. The high tides caused by the Moon´s gravity have an effect on the Moon as well; as a result, the Moon is slowly moving away from the Earth: its orbit is expanding by 4 cm (1.57 inches) every year.

The Moon is the fifth largest satellite
in the Solar System.
It orbits the Earth at a distance of 384 thousand kilometers. Its diameter is a quarter of the Earth’s. Its mass is only one eighty-first of that of the Earth. Therefore its gravity is weaker. Its surface warms up to 130⁰C (266 °F) during the day, but due to the strong heat radiation, it cools down to -160⁰C (-256 °F) at night.

Its surface is composed mainly of volcanic rocks, covered by a thick layer of debris. We can see darker, lower-lying basins, so-called seas, and lighter, higher plateaus on the Moon.
The basins, with the mountains and
craters ringing them, were created by gigantic meteorite impacts. However, the volcanic rock layer and craters
created by geological processes prove that there also used to be active volcanoes on the moon.

So far the Moon is the only celestial body
apart from the Earth where man has ever set foot.

The internal structure of the Moon is similar to that of Earth, it is composed of a crust, a mantle and a core. The solid crust is 20–60 km (12-37 mi) thick and is made up of volcanic rock. The upper mantle is also solid, with a partly molten layer below. The mantle has a thickness of 1200 km (746 mi). The outer core is about 300–350 km (186-217 mi) thick and is composed of molten substances, while the inner core is solid and has a diameter of about 150 km (93 mi).

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Formation of the Earth and Moon

This animation demonstrates how the Earth and the Moon were formed.

Lunar eclipse

Lunar eclipses occur when the Moon passes through the shadow cone of Earth

Phases of the Moon

During its orbit around the Earth, the visibility of the Moon's illuminated part constantly changes.

Tide

The rise and drop of sea levels caused by the gravitational force of the Moon.

Apollo 15 mission (Lunar Rover)

The animation shows the two-seater Lunar Rover used in the Apollo 15 mission

Earth

The Earth is a rocky planet with a solid crust and oxygen in its atmosphere.

Moon landing: July 20, 1969

Neil Armstrong, one of the crew members of Apollo 11 was the first man to set foot on the Moon.

Jupiter

Jupiter is the largest planet of the Solar System, it has two and a half times the mass of all the other planets combined.

Measuring time

The first calendars and time-measuring instruments were already used by ancient Eastern civilizations.

Satellite types

Satellites orbiting the Earth can be used for civilian or military purposes.

Solar eclipse

When the Sun, Earth, and the Moon are arranged in a straight line, the Moon can partially or completely obscure the Sun.

Sputnik 1 (1957)

The Soviet-made satellite was the first spacecraft to be launched into outer space (in October 1957).

The life-cycle of the Solar System

The formation of the Sun and the planets started with the contraction of a dust cloud about 4.5 billion years ago.

Interesting astronomy facts

This animation presents some interesting facts in the field of astronomy.

Moon radar experiment (Zoltán Bay, 1946)

In 1946 a Hungarian scientist was the first person to detect radar echoes from the Moon.

The Solar System; planetary orbits

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The Sun

The diameter of the Sun is about 109 times that of the Earth. Most of its mass consists of hydrogen.

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