The Moon is the fifth largest satellite in the Solar System, and it is the second-brightest object in the sky after the Sun. The Moon has a radius of 1.737 kilometers / 1.079 miles and a diameter of 3.474 km / 2.158 mi. It is only 384.400 km / 238.855 mi away from Earth. The Moon orbits the Earth once every 27 days. The Moon is unique in that it is the only spherical satellite orbiting a terrestrial planet.


The Moon is made of rock and metal—just like the Earth and the other rocky planets (Mercury, Venus, and Mars). Like the Earth, the Moon has layers. The innermost layer is the lunar core. It only accounts for about 20% of the diameter of the Moon. Outside the core is the largest region of the Moon, called the mantle. The lunar mantle extends up to a distance of only 50 km below the surface of the Moon. The outermost layer of the Moon is called the crust, which extends down to a depth of 50 km.


There are 8 different types of moon phases. Some of them are,

  • New moon:

New moon occurs when the moon is on the same side of Earth as the sun. New moons generally can’t be seen. They cross the sky with the sun during the day, and the moon’s shadow side is pointed toward Earth. A new moon is visible only during a solar eclipse.

  • Waxing crescent:

The waxing crescent phase is the moon’s first step toward fullness. In this phase, the moon is completely invisible (while it’s new) until a tiny sliver is illuminated. The moon is considered a crescent only when less than one half of it is visible.

  • First-quarter:

First Quarter Moon is the second primary Moon phase when the Moon has reached the first quarter of its orbit around Earth, hence the name.

  • Waxing gibbous:

The waxing (growing) gibbous Moon rises afternoon, transits the meridian after sunset, and sets after midnight.

  • Full moon:

The full moon is the lunar phase when the Moon appears fully. This occurs when Earth is located between the Sun and the Moon. A full moon occurs about once a month when the earth, sun, and moon are in a line and the earth is between the other two. The sun fully illuminates the side of the moon we can see from the earth. The full moon is the midpoint of the lunar cycle, which is the 29-day period from one new moon to the next.

  • Waning gibbous :

The Waning Gibbous Moon rises after sunset but before midnight and doesn’t set until after sunrise.

  • Third-quarter:

The Third Quarter Moon is when the opposite half of the Moon is illuminated compared to the First Quarter. Which half you see lit up depends on where you are on Earth. Only 50% of the Moon is illuminated during its third-quarter phase.

  • Waning crescent:

The waning crescent is the last phase of the moon. During this phase, the illuminated part of the moon gets smaller and smaller, until the cycle meets its end, starting again with the new moon.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s