By Alexander Merz · Updated on · Details checked on 13 October 2026
The Moon is our closest cosmic neighbour and the very first object most stargazers ever point a telescope at. Earth’s natural satellite is far more than a bright disc in the night sky: craters, frozen lava seas, mountain ranges and hairline rilles all reveal themselves to anyone who takes the time to look. Below you’ll learn what the Moon really is, how it formed, and how to observe it at its best.
⚡ The quick answer: The Moon is Earth’s natural satellite, orbiting at an average distance of about 384,000 km. It spins on its axis in exactly the time it takes to circle Earth (27.32 days), so it always shows us the same face. You can enjoy it with nothing more than a pair of binoculars, and the best views are along the terminator — the line between light and shadow — where craters stand out in dramatic relief.
What is the Moon?
Earth has a single natural satellite — a rocky, roughly spherical body we simply call the Moon. Strictly speaking, “the Moon” is our own; in astronomy the word “moon” is also the general term for any natural satellite orbiting a planet in the solar system.
The Moon orbits Earth at an average distance of 384,000 km and always presents the same face to us. Why? Because it takes just as long to rotate once on its axis as it does to complete one orbit of Earth — about 27.32 days. This “synchronous rotation” is the result of tidal forces from Earth acting on the Moon over millions of years until its spin became tidally locked.
Relative to its planet, the Moon is the second-largest satellite in the solar system, behind only Charon (the moon of the dwarf planet Pluto). In absolute terms it ranks fifth largest. Its surface gravity is only about one-sixth of Earth’s.
How did the Moon form?
With a diameter roughly one-quarter that of Earth, the Moon is strikingly large compared with its parent planet. According to accepted models, two bodies this big could not have formed side by side — so where did it come from?
Several hypotheses exist, but the most widely accepted is the giant-impact theory. Early in its history, Earth is thought to have been struck by a Mars-sized body. This colossal collision blasted the impactor and a large portion of Earth’s crust out into space.
Most of that debris settled into a ring around Earth, where material gradually clumped together into an ever-larger body: the proto-Moon. After roughly 10,000 years, all the surrounding matter had gathered into the newly born Moon. A key piece of supporting evidence is that the Moon’s composition closely matches Earth’s crust. Alternative ideas — the fission, capture and co-accretion theories — also exist.
What is the Moon made of?
The Moon has a layered, shell-like structure that differs from Earth’s in both composition and thickness. It carries a comparatively thick crust with a surprising quirk.
The crust is noticeably thinner on the near side facing Earth (about 60 km) than on the far side (about 150 km). As a result, the Moon’s centre of mass is offset by roughly 2 km from its geometric centre. Beneath the crust lie the outer, middle and inner mantle. Except for part of the inner mantle, these layers have solidified — unlike Earth’s molten mantle. The core is thought to consist of a solid iron centre surrounded by a fluid outer layer.
The Moon’s surface
The face of the Moon is a familiar sight: even with the naked eye we can pick out different features on its surface. A beginner telescope multiplies that detail many times over. One caveat, though: with an apparent magnitude of -12.7 the Moon is dazzlingly bright through an instrument, so a lunar filter is well worth having.
The lunar seas (dark patches)
The large dark patches visible to the naked eye once reminded people of oceans, so they were named “seas” (Latin maria). We now know they contain no water at all: they are broad plains of solidified lava dating from the Moon‘s formation. Bombarded by impacts in its youth, the Moon let magma well up into deep craters, where it cooled into flat plains.
Craters
The Moon is peppered with craters. During the “Late Heavy Bombardment” of its youth it was struck by countless bodies, and it is still hit by asteroids today. Because it has no active plate tectonics, no weathering and no appreciable atmosphere, its craters never fade away — meaning we can see almost every impact it has ever suffered.
Many craters display bright radial streaks, or “rays,” caused by glassy material formed on impact and flung outwards in all directions. Being more reflective, it appears brighter. The crater Tycho (named after the Danish astronomer Tycho Brahe) is the most striking example.
Mountains
The Moon’s mountain ranges often ring vast seas, a clue that they were thrown up by the impact of very large objects. Some peaks reach 11,400 m — taller than Mount Everest.
Rilles and rifts (through the telescope)
Even modest telescopes reveal rilles and rifts across the Moon‘s surface. The channels are thought to be collapsed lava tubes, while the rifts may have formed as molten rock cooled and contracted.
The far side of the Moon
The far side looks fundamentally different from the near side, with almost none of the dark maria. One explanation involves the tidal forces Earth exerts on the Moon, which concentrated molten rock on the near side during formation. Thanks to synchronous rotation the Moon always shows us the same hemisphere, so only spacecraft have photographed the other side. Even so, the phenomenon of libration — the Moon gently rocking on its axis — lets us glimpse slightly more than half of its surface over time.
The phases of the Moon
Exact dates and times for every full moon: our full moon calendar 2026 and 2027 lists all 25 of them, with the traditional names and a conversion table for UK, US, Indian and Australian time.
The Moon’s phases trace the movement, as seen from Earth, of the light-shadow boundary (the terminator) across the lunar surface. As the terminator shifts, the illuminated portion grows or shrinks. The full cycle is divided into four main phases of roughly a week each. You’ll find every date in our moon calendar.
Each phase has its own page with dates and observing notes: the new moon, the waxing moon and the waning moon. When the full moon passes through Earth’s shadow it turns copper red — that is the blood moon.
The table below sums up, phase by phase, what is best to observe — because each phase highlights different features:
| Phase | Illumination | Best features to observe |
|---|---|---|
| New Moon | 0% | Moon invisible: great for deep-sky, not for the Moon itself |
| Waxing crescent | ~25% | Craters along the terminator, Mare Crisium, earthshine |
| First quarter | 50% | Prime time: sharp relief along the terminator, the Apennine Mountains |
| Waxing gibbous | ~75% | Large maria, rilles and rifts in strong contrast |
| Full Moon | 100% | Ray craters Tycho and Copernicus; very glaring, a filter helps |
| Waning gibbous | ~75% | Western terminator, features on the western limb |
| Last quarter | 50% | Excellent before dawn: craters in relief on the eastern side |
| Waning crescent | ~25% | Thin crescent at dawn, earthshine |
The orientation of the crescent flips depending on whether you observe from the northern or southern hemisphere; near the equator it opens upwards or downwards.
How the Moon affects Earth
The Moon shapes Earth in many ways and probably played a decisive, if indirect, role in the origin of life. Through its gravity it drives the tides: the oceans’ waters “follow” the Moon as it orbits. This rhythmic cycle of wet and dry along the coasts is thought to have provided an ideal habitat for early life to take hold.
The Moon also stabilises Earth’s axial tilt, which would otherwise swing wildly over time. Without it, constant shifts in the axis would trigger dramatic climate extremes, making the evolution of complex life far harder.
How do I observe the Moon?
To get started with the Moon, a simple pair of binoculars is enough to reveal the first details, turning craters and seas into a genuine spectacle. To hunt down the most famous craters and maria, a beginner telescope works wonders.
The most rewarding view is along the terminator, where contrast is at its peak. Because the Moon is so bright, a lunar filter is recommended when using a telescope. For 1.25-inch eyepieces the Apertura 1.25" Moon FilterOmegon Premium Moon Filter 1.25″ is all you need (at $14.95€ 19.90) – spending more buys you nothing here.
The single most spectacular thing the Moon does is slide into Earth’s shadow. The most recent one was the partial lunar eclipse on 28 August 2026 — the Moon set while still up to 51 % covered. The next one visible from Britain and Ireland falls on 21 February 2027; our page has the recap with the exact times for eleven UK and Irish cities plus every eclipse through to 2032.
Our tip for getting started without breaking the bank: a good pair of 10×50 binoculars — light, instantly usable and perfect for sweeping the seas and spotting the larger craters.
Perfect for the Moon: Omegon Brightsky 10x50 Binoculars
Bright, high-contrast binoculars: perfect for the Moon, star clusters and Milky Way fields, handheld.
Price: € 289
* Affiliate link: if you buy through this link we may earn a small commission from Astroshop or High Point Scientific, at no extra cost to you.
Humans on the Moon
To this day the Moon remains the only celestial body humans have ever set foot on.
The past
Technical exploration began with space probes in the early 1960s: first simple flybys, then studies from lunar orbit, and finally landing and surface analysis. In 1969 the Apollo missions put the first humans on the Moon. In all, the Apollo programme took 12 people to the surface between 1969 and 1972, returning every one of them safely.
The future
Interest in the Moon has surged again in recent years, driven in part by private space companies that see it as a launch base for missions to Mars and beyond. The logic is sound: lifting off from the Moon is far cheaper thanks to its low gravity. At the poles, some crater floors never see sunlight and trap water ice in meaningful amounts. Oxygen, meanwhile, is abundantly bound in the lunar regolith; it could supply a base and, combined with water, help synthesise rocket propellant. A lunar station could therefore become an ideal staging post for future missions into the deep sky.
FAQ
How far is the Moon from Earth?
The average distance to the Moon is 384,000 km. Because its orbit is elliptical, it ranges from a near point (perigee, 363,000 km) to a far point (apogee, 405,500 km).
How long does it take to travel to the Moon?
The Apollo 11 astronauts needed about 76 hours (3.16 days) to reach the Moon aboard their Saturn V rocket. Counting launch, orbital manoeuvres around Earth and the Moon, and the landing itself, the full journey took roughly 8 to 9 days.
Why does the Moon shine?
The Moon produces no light of its own — it reflects sunlight. Its reflectivity (albedo) is just 0.12, only about a third of Earth’s. The reason it looks so bright in the night sky is its small distance in astronomical terms. During a new moon, the near side glows faintly in the light Earth reflects back onto it (earthshine).
Is the Moon a planet?
No. The Moon meets the criteria of a natural satellite: it orbits a much more massive object in a fixed orbit. Because its mass is significant relative to Earth’s, however, the pair is occasionally described as a “double-planet system.”
Who owns the Moon?
The 1967 Outer Space Treaty, meant to settle exactly these questions, contains many gaps and grey areas. No binding follow-up agreement has been reached since, so ownership of the Moon remains legally uncertain.
How many people have walked on the Moon?
The Apollo programme took 12 people to the surface of the Moon between 1969 and 1972. No crewed mission has returned since, though several programmes aim to send astronauts back in the coming years.
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