the moon

The Moon is a rocky, spherical celestial body that revolves around the Earth. Together, they form a system that has its own characteristics, characterized by its proximity to the Earth.[١]Where the distance between the Earth and the Moon is estimated at 238,855 miles (384,400 km), which is an inch away from the Earth annually, and the Moon is smaller than the Earth, with a radius of about 1,079.6 miles (1737.5 km).[٢]

The movement of the moon around the earth

The moon moves in space with a movement very similar to the movement of the earth, and it is noted that the moon in the sky is sometimes bright and sometimes dark, and sometimes part of it is dark and the other part is bright and luminous, and these changes in the proportion of illumination of the moon are caused by the continuous movement of the moon in space. The moon has two types of motion: revolutionary motion and rotational motion.[٣]

revolutionary movement

rotational motion

Rotation motion is the movement of the moon around its axis. The moon, during its movement around the earth, is at the same time revolving around its axis, and in the rotational motion, the moon also needs 27 days to complete its revolution around its axis, noting that the earth needs 24 hours to complete its rotation. Its rotational motion, meaning that the moon’s rotational motion is very slow compared to the Earth’s rotational motion, and this explains why one side of the moon can be seen from the Earth. The other side cannot be seen from the Earth, so it was called the dark side of the moon.[٣]

phases of the moon

The phases of the moon or the phases of the moon are the phases that the moon goes through while revolving around the earth during one month, and in each phase the moon’s illumination percentage varies.[٤]The moon goes through eight phases:[٥]

  • New Moon: It is the first phase of the moon’s phases, and this phase occurs when the moon is between the earth and the sun, in which the moon appears dark, as the sunlight falls on the other side of the moon.
  • The phase of the growing crescent (in English: Waxing Crescent Moon): In this phase, the light of the moon begins to appear gradually in the form of a crescent, and the size of the luminous moon increases every night until half of the moon’s disk is illuminated.
  • The First Quarter Moon: In this phase, the moon reaches the first quarter of its orbit while revolving around the Earth (so it was called by this name), during which 50% of the moon is seen in a luminous form.
  • Waxing Gibbous Moon: In this phase, the illuminated moon increases in size, as the moon is larger than a semicircle and smaller than a full circle.
  • Full Moon Phase: The moon in this phase is called a full moon, as it is the brightest body in the sky after the sun, because it is fully lit, and this phase occurs when the Earth is between the moon and the sun.
  • Waning Gibbous Moon Phase: In this phase, the moonlight wanes and begins to diminish gradually.
  • The Third Quarter Moon phase: It is the phase of the last quarter, which occurs when the opposite half of the moon is lit compared to the first spring moon.
  • Waning Crescent Moon: This is the last phase, in which the moon’s light gradually decreases until it reaches the shape of a crescent, then returns to the first phase of the new moon, to start a new cycle of the phases of the moon.

Lunar eclipse

Lunar eclipses are a natural phenomenon that occurs on the moon when the Earth lies between the moon and the sun along the line connecting them, where the Earth blocks the sun’s rays from the moon and its shadow falls on the moon, and this phenomenon occurs during the full moon phase, i.e. when it is full.[٦]

types of eclipse

The type of eclipse is determined based on the amount of shadows falling on the surface of the moon. There are three types of lunar eclipses:[٦]

  • Penumbral Eclipse: This type of eclipse occurs when part of the moon falls in the semi-shadow region of the Earth, and this region of the shadow is not completely opaque, so the moon here dims its light and may appear golden or gray.
  • Total Lunar Eclipse: In this type of eclipse, the Earth’s shadow covers the entire moon, but it is not a requirement that the moon appear dark, due to the refraction of sunlight in the atmosphere, which may give the moon a little illumination.
  • Partial Lunar Eclipse: This type occurs when a part of the moon falls in the umbra, which is the shadow of the Earth, which has no solar radiation, and the rest of the moon remains luminous.

The eclipse does not occur every month

A lunar eclipse occurs when the sun, the moon and the Earth are in one straight line, and this case occurs monthly in the phase of the full moon, but the phenomenon of lunar eclipses does not occur monthly with the availability of the conditions for the occurrence of the eclipse every month, and the reason for this is that the moon’s orbit tilts at an angle of approximately five degrees To the Earth’s orbit, and if the moon was revolving at the same level as the Earth’s rotation around the sun, the eclipse would occur monthly, and this means that the moon, the sun and the Earth are not always exactly one straight line, but it may be a small deviation, and this deviation is the reason for the incompleteness of the condition Eclipse occurs.[٧]

the reviewer

  1. ↑ James D. Burke, “Moon”, www.britannica.com, Retrieved 5-5-2019. Edited.
  2. ↑ “Earth’s Moon”, solarsystem.nasa.gov, Retrieved 29-5-2019. Edited.
  3. ^ a b b Josh Corbat, “Movements of the Moon Lesson for Kids: Orbit & Rotation”, study.com, Retrieved 29-5-2019. Edited.
  4. ↑ Tim Sharp (10-4-2019), “2019 Moon Phases Calendar”, www.space.com, Retrieved 29-5-2019. Edited.
  5. ↑ John Lindell (24-4-2017), “Definition of Phases of the Moon”, sciencing.com, Retrieved 29-5-2019. Edited.
  6. ^ AP Anne Helmenstine (11-2-2018), “Lunar Eclipse and the Blood Moon”, www.thoughtco.com, Retrieved 29-5-2019. Edited.
  7. ↑ “Why no eclipse every full and new moon?”, earthsky.org, Retrieved 5-5-2019. Edited.

The movement of the moon around the earth

Writing – on the date : – Last updated: 2022-05-13 02:09:01