His origin
The origin of the Moon has been the subject of various scientific theories. The most accepted theory is called the giant impact hypothesis. According to this theory, about 4.5 billion years ago, shortly after Earth formed, a Mars-sized object slammed into the young Earth. This impact was so violent that it threw enormous amounts of matter from Earth into space.
Much of this material orbiting Earth began to come together under gravity to form the Moon, forming the internal structure of the Moon we know today.
Moon Phases
Moon phases correspond to the different appearances of the Moon as seen from Earth during a lunar month, which lasts approximately 29.5 days .
These phases, mainly due to the relative position of the Moon, the Earth and the Sun, are:
- New Moon (0% illuminated): The illuminated side of the moon is entirely turned toward the sun and is not visible from Earth. It is the beginning of the lunar cycle.
- First crescent (1% - 49% lit): A small part of the lit side of the moon is visible in the shape of a crescent.
- First Quarter (50% lit): Half of the moon's lit side is visible as a semicircle, resembling a "D".
- Waxing Gibbous (51% - 99% lit): Part of the lit side of the moon is visible, and the moon appears as an increasingly wide crescent.
- Full Moon (100% illuminated): The entire illuminated side of the moon is visible from Earth, giving the appearance of a luminous disk.
- Waning Gibbous (51% - 99% illuminated): The moon appears as a progressively narrower crescent.
- Last Quarter (50% lit): Half of the lit side of the moon is visible as a semi-circle, resembling a "C".
- Last crescent (1% - 49% illuminated): A small part of the illuminated side of the moon is visible in the shape of a crescent.
The Moon in a few figures
- 238,854 mi: this is the average Earth-Moon distance.
- 2,159 mi: this is the diameter of the Moon, a little more than a quarter of the size of the Earth.
- 4.5 billion years: this is the estimated age of the Moon. Almost the same age as our blue planet.
- 1/6: this is the ratio between lunar gravity and terrestrial gravity. That is to say, if you weigh 60kg on Earth, you would only weigh 10kg on the Moon.
- 29.5 days: also called a synodic month, this is the time it takes for the Moon to go through all its phases.