Moon Facts for Kids

Moon quick facts

• The Moon moves about 3.8 cm (1.5 inches) further from Earth every year, measured with mirrors that Apollo astronauts left behind.
• About 30 Earths could fit in the gap between Earth and the Moon.
• Nobody saw the far side of the Moon until a Soviet spacecraft flew past in 1959.
• The first rocks from the Moon’s far side reached Earth on 25 June 2024, brought back by China’s Chang’e 6.
• In April 2026 the Artemis II crew travelled 252,756 miles from Earth, further than any people before them.

What is the Moon?

The Moon is a ball of rock that travels around Earth. It is Earth’s only natural satellite. A satellite is anything that orbits, or circles, a bigger object in space.

The Moon is the brightest thing in our night sky, yet it makes no light of its own. What we see is sunlight bouncing off its grey, dusty surface. The same Sun that lights our days lights the Moon too.

People have studied the Moon for thousands of years. It is still the only place beyond Earth where humans have walked.

How big is the Moon compared with Earth?

The Moon is about 3,480 km (2,160 miles) across. That is less than a third of the width of Earth.

Here is a way to picture it. If Earth were the size of a small coin, the Moon would be about as big as a peppercorn.

The Moon is small, but it is not like other moons. Most planets have tiny moons compared with their own size. Ours is large next to its planet, and scientists think that helps keep Earth steady as it spins.

Feature	The Moon	Earth
Width	about 3,480 km (2,160 miles)	more than three times wider
Gravity	about one-sixth of Earth’s	full strength
Sunrise to sunrise	about 29.5 Earth days	24 hours
Air	almost none	a thick layer we can breathe
Daytime sky	black	blue
Temperature	about 127°C (260°F) by day, −173°C (−280°F) at night	much milder
Water	ice hidden in dark craters near the poles	oceans, rivers and rain

How far away is the Moon?

On average, the Moon is about 384,400 km (238,855 miles) from Earth. That gap is so wide that about 30 Earths could fit in it, lined up side by side.

The distance is also slowly growing. Each year the Moon moves about 3.8 cm (1.5 inches) further away from us. That is about the width of a matchbox, every single year.

How do scientists know this so exactly? Apollo astronauts left special mirrors on the Moon, called laser reflectors. The first was set up in 1969, and Apollo 14 and 15 added more. Scientists on Earth fire laser beams at the mirrors and time how long the light takes to bounce back. The mirrors are still in use today.

How did the Moon form?

Most scientists think the Moon was born in a giant crash. This idea is called the giant-impact model.

Long ago, when Earth was very young, a planet about the size of Mars smashed into it. Scientists have named that lost planet Theia. The crash melted both worlds. A small part of the mixed-up rock was flung out into space, where it slowly clumped together, piece by piece, to make the Moon. Within about 100 million years, the young Moon’s sea of melted rock had mostly cooled and hardened.

The best evidence came back with the Apollo astronauts. Their Moon rocks turned out to be chemically very like rocks on Earth. That suggests the two share a history. A Moon that formed somewhere else and was caught by Earth’s gravity would look very different.

Scientists are still not sure about the details, though. They run computer models with Theia at different sizes, hitting Earth at different angles, to find the best match. Some think Theia and the young Earth were made of almost the same stuff to begin with. The giant-impact model is the leading idea, but it is not settled.

Why we always see the same side

Look at the Moon on any night of the year and you will see the same face, with the same dark patches in the same places. The reason has a name. The Moon is tidally locked to Earth.

Tidally locked means the Moon spins round exactly once in the time it takes to orbit Earth once. Both take about 27 days. As it travels around us, it turns at just the right speed to keep the same side pointing our way.

Try it with a friend. Walk in a circle around them while always facing them. By the time you get back to the start, you have turned all the way round once. Your friend never saw the back of your head.

The side we never see is called the far side. Nobody saw it at all until 1959, when a Soviet spacecraft flew past and took pictures. Its crust is thicker than the near side’s, up to about 60 km (37 miles) deep.

The far side is not dark, though. The Sun lights it just as often as the side we see. When we have a new Moon, the far side is in full daylight.

The phases of the Moon

The Moon seems to change shape through the month. It never really does. Sunlight always lights exactly half of it, just as half of Earth always has daytime.

What changes is how much of that lit half we can see from Earth. As the Moon travels around us, we see it from a different angle each night. These changing shapes are called phases. When the lit part is growing, we say the Moon is waxing. When it is shrinking, the Moon is waning.

The whole cycle, from one new Moon to the next, takes about 29.5 days. That is longer than the 27 days the Moon takes to orbit Earth. The reason is that Earth is moving around the Sun at the same time. The Moon needs a couple of extra days to catch up and line up with the Sun again.

Phase	What you see	About how many days after new Moon
New Moon	almost nothing: the lit side faces away from us	0
Waxing crescent	a thin curve of light on the right (seen from the UK)	3 to 4
First quarter	the right half lit	7
Waxing gibbous	more than half lit, and growing	11
Full Moon	the whole face lit	15
Waning gibbous	more than half lit, and shrinking	18
Third quarter	the left half lit	22
Waning crescent	a thin curve of light on the left	26

If you live in the Southern Hemisphere, the pattern is flipped. There, a waxing crescent is lit on the left.

A calendar month is usually a little longer than 29.5 days. So now and then, two full Moons fall in the same month. The second one is often called a blue moon. Despite the name, it looks just like any other full Moon.

Eclipses of the Sun and Moon

An eclipse happens when the Sun, Earth and Moon line up in space. There are two kinds.

A solar eclipse happens at new Moon. The Moon passes between the Sun and Earth, and its shadow falls on part of our planet. During a total solar eclipse, the Moon covers the Sun’s bright face completely, and the sky goes dark for a few minutes.

A lunar eclipse happens at full Moon. This time Earth sits between the Sun and the Moon, and Earth’s shadow falls on the Moon. In a total lunar eclipse, the Moon often turns a coppery red. Earth’s air scatters away most of the blue in sunlight, and the leftover red light bends onto the Moon. That is why people sometimes call it a blood moon.

We do not get eclipses every month. The Moon’s path around Earth is slightly tilted, so most months it passes just above or below the line between Earth and the Sun.

A lunar eclipse is completely safe to watch with your eyes or a telescope. A solar eclipse is not. You need proper eclipse glasses, and an adult should help.

How the Moon makes tides

If you have spent a day at the seaside, you have seen the Moon at work. The rise and fall of the sea, called the tide, is mostly caused by the Moon’s gravity.

The Moon pulls on Earth’s oceans and makes the water bulge. As Earth spins, most coasts pass through two bulges each day, giving most beaches two high tides and two low tides. From one high tide to the next takes a little over 12 hours.

The Sun helps too, but it is so far away that its pull on the tides is a little less than half the Moon’s. Twice a month, the Sun, Moon and Earth line up. Their pulls add together and make extra-high tides called spring tides. They have nothing to do with the season. When the Sun and Moon pull at right angles, their pulls partly cancel out. Then we get gentler tides called neap tides.

Gravity on the Moon

Gravity on the Moon is about one-sixth of Earth’s. Gravity is the pull that makes things fall and keeps your feet on the ground. The Moon has much less mass than Earth, so its pull is much weaker.

That changes what you would weigh. Bathroom scales that show 30 kg on Earth would show only about 5 kg on the Moon. You would not have lost any of yourself. The Moon would simply be pulling on you less.

You could jump much higher, too. With the same push from your legs, you would rise about six times as high and float down slowly. A real astronaut would find it harder. Their bulky spacesuits made it hard to bend, so nobody set any high-jump records.

Boiling days and freezing nights

The Moon has almost no air. Its atmosphere is so thin and weak that it cannot hold in heat or block the Sun’s harmful rays.

Without that blanket, temperatures swing wildly. In sunlight, the ground can reach about 127°C (260°F). That is hotter than boiling water. At night it drops to about −173°C (−280°F), far colder than any home freezer.

Days and nights there are long, too. Sunrise to sunrise takes about 29.5 Earth days. So one spot on the Moon gets about two weeks of sunshine, then about two weeks of darkness.

No air also means the sky is always black, even when the Sun is up. On Earth, air scatters blue sunlight all over the sky. That is why the sky is blue here. The Moon has no air to do that, so astronauts saw a black sky above a bright, sunlit ground.

Craters, maria and moonquakes

The Moon’s surface is covered in craters. A crater is a round hollow made when a rock from space smashes into the ground. Many of these rocks are chunks of asteroids.

Wind, rain and moving land slowly wipe craters off Earth, but the Moon has no weather, so its craters last for billions of years. One of the best known is Tycho Crater. It is more than 85 km (52 miles) wide, wider than the whole of Greater London.

Now look at the dark patches on the Moon’s face. They are called maria, which is Latin for “seas”. Early astronomers thought they might be water. They are really huge old craters that filled up with runny lava. Like the lava from a volcano on Earth, it cooled into dark rock. The maria formed between about 4.2 billion and 1.2 billion years ago.

The Moon also shakes. Apollo astronauts left instruments called seismometers, which measure shaking, and they recorded moonquakes. Some happen deep inside, when Earth’s gravity tugs and stretches the Moon. Others happen because the Moon is slowly shrinking as it cools, or when a space rock hits. The strongest shallow moonquakes can last more than 10 minutes. An earthquake usually lasts only seconds or a few minutes.

Water ice at the poles

For a long time, people thought the Moon was bone dry. Now we know it has water ice.

Near the Moon’s north and south poles, the Sun always stays low in the sky. Some deep craters there have floors that sunlight never reaches. Scientists call these permanently shadowed regions. They stay bitterly cold all the time, and ice has built up inside them.

That ice matters for the future. Scientists hope astronauts could one day use it for drinking water. It might even be split up to make air to breathe and fuel for rockets. This is one reason so many new missions are heading for the Moon’s south pole.

The Apollo Moon landings

Between 1969 and 1972, NASA’s Apollo missions landed 12 American astronauts on the Moon. They are the only people who have ever walked on another world.

The first two were Neil Armstrong and Buzz Aldrin of Apollo 11, in July 1969. The last two were Eugene Cernan and Harrison Schmitt of Apollo 17, in 1972. Nobody has stood on the Moon since.

The astronauts brought home 382 kg (842 pounds) of Moon rock and soil, which is about as heavy as five grown-ups put together. Scientists around the world still study those samples today, using tools that did not exist in the 1970s.

They left things behind as well. Besides flags and footprints, they set up the laser mirrors and the seismometers that taught us about moonquakes. With no wind or rain to wipe them away, their footprints are likely still there.

Moon missions today

After Apollo, people stopped visiting the Moon for more than 50 years. Robots kept going, though. More than 105 robotic spacecraft have been launched to explore it, and several countries have now landed there.

In August 2023, India’s Chandrayaan-3 mission landed a lander and a small rover near the Moon’s south pole. That is the icy region scientists are most keen to explore.

In June 2024, China’s Chang’e 6 landed on the far side of the Moon, inside a huge basin. It scooped up rock and soil and sent them back to Earth. The capsule landed in Inner Mongolia on 25 June 2024. They were the first rocks ever collected from the far side.

NASA’s plan to send people back is called Artemis. In April 2026, the Artemis II crew flew around the Moon and home again in just over nine days. The four astronauts were Reid Wiseman, Victor Glover and Christina Koch of NASA, and Jeremy Hansen of the Canadian Space Agency. They travelled 252,756 miles (about 406,800 km) from Earth. No humans had ever been further from home. They did not land, but they did pass around the far side.

What comes next? We checked NASA’s Artemis pages on 11 September 2026. NASA says Artemis III is planned for 2027, but it will not land. It will stay close to Earth and test the landers that two companies, SpaceX and Blue Origin, are building. NASA is aiming for the first Artemis landing on the Moon with Artemis IV, in 2028. Space missions often change their dates, so check NASA’s website for the latest news.

You can read about the other worlds astronauts may visit one day in our space facts for kids.

Three things people get wrong

1. There is no “dark side” of the Moon. The side we never see is the far side, and it gets just as much sunlight as the near side. Every part of the Moon has about two weeks of day and two weeks of night. At new Moon, when we see almost nothing, the far side is in full sunshine.
2. The Moon does not make its own light. It shines only because it reflects sunlight. That is why we see phases. If the Moon glowed by itself, it would look full every night.
3. The Moon is not bigger when it is near the horizon. It only looks bigger. Photos taken with the same camera settings show it is the same width low in the sky and high up. You can test it with your fingernail, as NASA suggests. Nobody has a complete explanation for this Moon illusion yet, but it happens in your brain, not in the sky.

Frequently asked questions

How far away is the Moon?

The Moon is about 384,400 km (238,855 miles) from Earth on average. About 30 Earths would fit in the gap, and the Moon drifts about 3.8 cm (1.5 inches) further away each year.

How big is the Moon compared with Earth?

The Moon is about 3,480 km (2,160 miles) across, which is less than a third of Earth’s width. If Earth were the size of a small coin, the Moon would be about as big as a peppercorn.

How many people have walked on the Moon?

Twelve American astronauts walked on the Moon during NASA’s Apollo missions between 1969 and 1972. Nobody has walked on the Moon since 1972.

Is there a dark side of the Moon?

No part of the Moon stays dark all the time. The far side, which never faces Earth, gets just as much sunlight as the near side. People call it dark only because we never see it.

Why does the Moon change shape?

The Moon does not really change shape. Sunlight always lights half of the Moon, and as the Moon orbits Earth we see different amounts of that lit half. The cycle of phases takes about 29.5 days.

Why is the sky on the Moon black?

The Moon has almost no air. On Earth, air scatters blue sunlight across the sky, but the Moon has no air to do that, so its sky looks black even in the daytime.

When will astronauts land on the Moon again?

NASA’s Artemis II crew flew around the Moon in April 2026 without landing. As of September 2026, NASA plans a test mission in Earth orbit for 2027 and is aiming for the first Artemis Moon landing in 2028.

Sources

• NASA Science: Earth’s Moon facts — size, distance, gravity, temperatures, formation, tidal locking, the first view of the far side in 1959, Tycho Crater, the maria and ice at the poles
• NASA Science: Moon phases — the eight phases, the 29.5-day cycle, tidal locking and why the far side is not dark
• NASA: the Apollo experiment that keeps on giving — the Moon moving 3.8 cm (1.5 inches) further away each year, measured with laser reflectors left by Apollo 11, 14 and 15
• NASA Science: Moon exploration — the 12 Apollo moonwalkers between 1969 and 1972, the 382 kg of samples they brought back, and Artemis II
• NASA: Artemis — the Artemis II crew and distance record, and the plans for Artemis III in 2027 and a landing on Artemis IV in 2028 (checked 11 September 2026)
• Nature: first ever rocks from the Moon’s far side have landed on Earth — the Chang’e 6 far-side samples landing in Inner Mongolia on 25 June 2024