The Moon - Earths closest companion

wesknows
Feb 27
3 min read

Updated: Mar 1

Retro Moon cartoon, character with happy face and arms pointing.

Look up at the night sky, and what’s the brightest thing you see? That’s right—the Moon! It has guided explorers, inspired myths, shaped our calendars, and even influenced the tides. But what do we really know about our closest celestial neighbour?

Close-up of a bright, detailed full moon against a dark sky with scattered small stars, showing craters and lunar surface textures. — Credit: Rami Astro L.L.C

How Did the Moon Form?

There are a few theories about how the Moon came to be, but the most widely accepted one is called the Giant Impact Hypothesis.

a simulated sequence of how the moon was formed. step bu step moon formation — Formation of the moon, Credit Topinfopost

Around 4.53 billion years ago, a Mars-sized object (called Theia) collided with the early Earth.
The impact blasted rock, dust, and gas into space, forming a ring around Earth.
Over time, these fragments clumped together and formed the Moon.

This means that Earth and the Moon share a lot of the same materials, which is why scientists believe the Moon is essentially a piece of Earth that broke off long ago.

The Moon’s Surface and Structure

The Moon looks smooth from Earth, but up close, it’s covered in craters, mountains, and vast plains formed by billions of years of asteroid impacts.

Inside, the Moon has layers just like Earth:

Lunar surface with craters and rugged terrain in grayscale. Shadows enhance the textures and depth, creating a stark, desolate mood. — Credit: NASA

A solid iron-nickel core
A partially molten outer core
A rocky mantle and crust

With no atmosphere to protect it, the Moon’s surface is constantly bombarded by space debris, leaving it scarred with craters—some of which are billions of years old!

Moon Data Dump!

Diameter: 3,474 km (2,158 miles)

Distance from Earth: 384,467 km (238,857 miles)

Rotational Period: 27.32 days

Orbital Period: 27.32 days (same as its rotation!)

Surface Temperature: -173°C to 127°C (-280°F to 260°F)

Gravity: 1/6th of Earth's

Why Do We Always See the Same Side of the Moon?

Ever noticed that we only see one side of the Moon? That’s because of something called tidal locking.

The Moon takes 27.32 days to orbit Earth.
It also takes 27.32 days to rotate on its axis.
This means the same side is always facing us, while the far side (often called the “dark side”) remained a mystery until space probes visited it!

The Phases of the Moon

Did you know that the Moon doesn’t produce its own light? it just reflects the Sun’s light. As it orbits Earth, different amounts of the Moon’s surface are illuminated, creating the lunar phases.

Diagram of moon phases on a blue background, showing New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning Crescent in a circular layout.

The 8 Moon Phases:

New Moon – The Moon is between the Earth and Sun, so we can’t see it.
Waxing Crescent – A small sliver appears on the right side.
First Quarter – Half of the Moon is visible.
Waxing Gibbous – More than half is illuminated.
Full Moon – The entire face is lit up.
Waning Gibbous – The Moon starts shrinking.
Last Quarter – Half is visible again, but on the opposite side.
Waning Crescent – A tiny sliver remains before starting over.

Each full cycle takes about 29.5 days—which is why many ancient calendars were based on the lunar month!

The Moon’s Influence on Earth

The Moon does more than just light up our night sky—it has a major impact on Earth!

1. Tides

The Moon’s gravity pulls on Earth’s oceans, creating high and low tides. Without the Moon, ocean currents and even some ecosystems would be completely different!

Credit Nasa/Vi Nguyen

2. Stabilising Earth’s Tilt

Earth is tilted at 23.4 degrees, and the Moon’s gravity helps keep that tilt stable. Without the Moon, Earth’s tilt would wobble wildly, causing extreme climate changes!

Animation depicts a point orbiting another. Text reads: 2018-01-01 00:00, Moon, 0.000km/s, 357,401km. Black background, blue and pink points. — Orbital Pattern of the Moon

Missions to the Moon

For centuries, people dreamed of visiting the Moon—and in 1969, that dream became reality!

Apollo 11 – The First Moon Landing

On July 20, 1969, NASA’s Apollo 11 mission made history when astronauts Neil Armstrong and Buzz Aldrin stepped onto the lunar surface.

Astronaut on the moon stands near U.S. flag, lunar module in background. Gray surface with footprints, dark sky. Calm, historic scene. — Credit: NASA

Armstrong’s famous words:

"That’s one small step for man, one giant leap for mankind."

Since then, six Apollo missions have landed astronauts on the Moon, collecting rock samples and conducting experiments.

Moon Rock Sample at the Wings over the Rockies Museum in Colorado, USA.

Recent & Future Moon Missions

NASA's Orion spacecraft image with text about its mission to the Moon. Features details comparing Orion to Apollo and travel times to the ISS. — NASA's Artemis program plans to send humans back to the moon inn the coming years

Chinas Chang'e lunar spacecraft on the lunar surface with space in the background. Moon missions — Chang'e mission Credit: NASA

China’s Chang’e missions and private companies like SpaceX are also planning lunar exploration and potential Moon bases!

The Moon is more than just a rock in the sky—it has shaped our planet, inspired our cultures, and even set the stage for space exploration.

As scientists prepare for human missions to the Moon once again, who knows what exciting discoveries await? One thing is certain: the Moon will always be a source of wonder, curiosity, and exploration.