DEV Community: Constantine Kim

Around the Moon and back: the Moon in 2026

Constantine Kim — Wed, 21 Oct 2026 10:31:26 +0000

This year, the Moon had visitors again. In April, four people flew around it, and before the year is out it will rise twice more as a supermoon. Here is what happened, what comes next, and when to look up.

Four people went around it

Artemis II launched from NASA's Kennedy Space Center in Florida on April 1, 2026. Ten days later, on April 10, its Orion capsule splashed down off the coast of California after a trip around the Moon and back.¹

Crew member	Role	Agency
Reid Wiseman	Commander²	NASA³
Victor Glover	Pilot¹	NASA³
Christina Koch	Mission specialist¹	NASA³
Jeremy Hansen	Crew member	Canadian Space Agency³

On April 6, at 12:56 p.m. CDT, the crew passed the record Apollo 13 set in 1970 and became the farthest humans have ever traveled from Earth.³

What comes next

Not a landing, yet. NASA has reshaped Artemis III into a test mission in Earth orbit: an Orion capsule will carry astronauts up to practice docking with one or both of the planned lunar landers, Blue Origin's Blue Moon and SpaceX's Starship. It is expected in late 2027.⁴

Landings could come as early as 2028, the year Artemis IV is currently scheduled.²

A Moon that keeps moving

While we work our way back, the Moon keeps edging away, by about 3.8 centimeters a year.⁵ Scientists track that drift by aiming lasers at mirrors Apollo 11 astronauts left on the surface on July 21, 1969.⁵ We've written about why the Moon is drifting away: it comes down to ocean tides, and the same tides are slowly lengthening our days.

Look up

A supermoon is a full Moon that happens when the Moon is at, or near, the closest point in its orbit to Earth. Two are left in 2026:⁶

Date	Name	Where to look
November 24	Beaver Moon	Rises in the northeast before sunset, sets in the southwest before sunrise
December 24	Cold Moon	Rises in the northeast just before sunset, sets in the northwest as dawn breaks

Catch either one just after it rises, and it may look enormous. Most of that is the trick explained in Why the Moon looks bigger near the horizon. Either way, it is the same Moon the Artemis II crew saw up close this spring, a few centimeters farther away than it was last year.

NASA, "Artemis II crew returns to Earth" (April 2026): https://www.nasa.gov/?p=983425 ↩
FOX 35 Orlando, "Artemis II astronauts reflect on historic deep space mission as they undergo recovery" (April 16, 2026): https://www.fox35orlando.com/news/artemis-ii-astronauts-reflect-historic-deep-space-mission-undergo-recovery ↩
NASA, "NASA's Artemis II crew eclipses record for farthest human spaceflight" (April 2026): https://www.nasa.gov/news-release/nasas-artemis-ii-crew-eclipses-record-for-farthest-human-spaceflight ↩
Scientific American, "What we know—and what we don't—about NASA's Artemis III mission" (2026): https://www.scientificamerican.com/article/nasa-reveals-new-clues-to-2027s-artemis-iii-the-final-test-mission-before-a-moon-landing/ ↩
The Conversation, "How did the Moon end up where it is?": https://theconversation.com/how-did-the-moon-end-up-where-it-is-114930 ↩
BBC Sky at Night Magazine, "We'll get three supermoons in 2026": https://www.skyatnightmagazine.com/advice/supermoons-2026 ↩

Why the Moon looks bigger near the horizon

Constantine Kim — Tue, 13 Oct 2026 11:57:04 +0000

Catch the full Moon just as it clears the rooftops and it can look startlingly large — a huge orange disc hanging over the street. A few hours later, high in the sky, it looks like an ordinary small white coin.

The Moon didn't shrink. It never changed size at all. What changed was how your brain decided to read it.

This is the Moon illusion, and it is one of the oldest puzzles in astronomy. People have been noticing it, and arguing about it, for well over two thousand years.

The Moon is not actually bigger

Start with what a camera sees. Photograph the Moon on the horizon and again when it's high up, using the same lens, and the two discs come out essentially the same size. The Moon covers about half a degree of sky either way — roughly the width of your pinky fingernail held at arm's length.

If anything, the horizon Moon is very slightly smaller. When the Moon is overhead, you are standing on the side of Earth facing it. When it's on the horizon, you are off to one side, about one Earth radius farther away. That makes the horizon Moon around 1.5% smaller in angle — far too little for anyone to notice, but the opposite of what our eyes report.

What the atmosphere does, and doesn't, do

It is tempting to blame the air. Light from a low Moon passes through far more atmosphere than light from a high one, and that does change two things:

Effect	What it does to the low Moon
Scattering	Blue light is scattered out, so the Moon looks yellow, orange or red
Refraction	Light from the bottom edge is bent more than from the top, slightly squashing the Moon into an oval

Neither of these makes the Moon bigger. Refraction actually shortens it from top to bottom. The air explains the color, not the size.

Ancient writers did blame the atmosphere for the illusion. As early as the 11th century, the scholar Ibn al-Haytham argued that the answer lay instead in how we judge distance — and most modern explanations still follow that path.

So why does it look so big?

Nobody has a single, settled answer, but the leading explanations all come down to context. Your brain never judges size in isolation; it compares an object to whatever surrounds it.

The sky looks flattened. We tend to perceive the sky not as a perfect dome but as a shallow bowl, with the horizon seeming much farther away than the point straight overhead. The Moon makes the same-sized image on your eye in both places. If your brain assumes the horizon Moon is farther away, it concludes the Moon must be bigger to look that size — and that's what you "see".

There's something to compare it to. On the horizon, the Moon sits next to trees, houses and distant hills — things you know are big and far away. Seen beside them, the Moon looks huge. High in an empty sky, it has nothing to be measured against.

Relative size tricks. A circle surrounded by small shapes looks larger than the same circle surrounded by big empty space. Low on the horizon, the Moon is framed by small, detailed objects; overhead, it's surrounded by a vast blank sky.

These explanations probably work together, and researchers still debate how much each one contributes. What everyone agrees on is that the effect happens in perception, not in optics.

Try to break the illusion yourself

You can catch your own brain in the act next time there's a full Moon rising:

Use your finger. Hold your little finger at arm's length and cover the Moon with it near the horizon. Try again a few hours later when it's high up. It covers the same amount both times.
Look through a tube. Roll up a sheet of paper and look at the rising Moon through it, so you can't see the horizon. Without the trees and buildings around it, the Moon often shrinks back to normal.
Take a photo. Snap the Moon at the horizon and again later with the same zoom, then compare. The discs match.
Look at it upside down. The classic, slightly silly test: turn your back to the Moon, bend over and look at it between your legs. Many people find the illusion weakens or disappears.

What about supermoons?

There is one way the Moon really does change size in our sky. Its orbit is an oval, so its distance from Earth varies through the month. A full Moon at its closest point — popularly called a supermoon — is about 14% wider than a full Moon at its farthest.

That difference is real, but it is surprisingly hard to spot by eye without a side-by-side comparison. The horizon effect, which isn't real at all, looks far more dramatic.

So the next time a giant Moon rises over your street, enjoy it. Just know that the Moon hasn't changed — you're seeing your own brain working out distances, and getting this one beautifully wrong.

Why we always see the same side of the Moon

Constantine Kim — Tue, 13 Oct 2026 11:19:22 +0000

Look up at the Moon tonight and you'll see the same face your grandparents saw, and the same one people saw thousands of years ago. The same craters and the same dark plains. Every human who has stood on Earth has looked at the same side.

It is easy to assume this means the Moon doesn't rotate. It does. It turns once on its axis in about 27.3 days, which is exactly how long it takes to go once around Earth. Because those two motions match, the same side always faces us.

That match is not a coincidence. It has a name: tidal locking.

How Earth grabbed hold of the Moon

When the Moon formed, about 4.5 billion years ago, it almost certainly spun much faster than it does today. A day on the Moon was probably only hours long.

Earth's gravity changed that. The pull of gravity gets weaker with distance, so Earth tugged a little harder on the near side of the Moon than on the far side. That difference stretched the Moon slightly, raising two small bulges in its rock — one facing Earth and one facing away. These are tides, but in solid rock instead of water.

As long as the Moon spun faster than it orbited, its rotation kept carrying those bulges out of line with Earth. Earth's gravity kept pulling them back. Each time, the rock flexed, and that flexing turned a little of the Moon's spin into heat.

Over time, this acted like a brake. The Moon's spin slowed until there was nothing left to fight: its rotation matched its orbit exactly, and the bulges came to rest pointing straight at Earth. Once that happened, the braking stopped. The Moon has stayed locked ever since.

Astronomers think this happened fairly early in the Moon's history, at a time when the Moon was much closer to Earth and the tidal forces on it were far stronger.

The same trick, in reverse

If this sounds familiar, it should. It is the same mechanism behind why the Moon is slowly drifting away from Earth.

Earth has tidal bulges too, raised by the Moon. Earth still spins much faster than the Moon orbits, so those bulges are still being dragged out of line, and Earth's rotation is still being braked. That is why our days are slowly getting longer, and why the Moon is gaining energy and drifting outward.

The Moon simply finished the process first. It is far smaller than Earth and felt a much stronger tidal pull, so it locked billions of years ago. Earth is still on the way.

We actually see more than half

Strictly speaking, we don't see only half the Moon. Over time we see about 59% of its surface. The Moon wobbles slightly as seen from Earth, and these wobbles are called librations.

Cause	What happens	What we see
Its orbit is an oval, not a circle	The Moon moves faster when closer to Earth and slower when farther away, but its spin stays steady	A little extra around the left and right edges
Its orbit is tilted	The Moon spends part of each month slightly above or below Earth's equator	A little over the top and under the bottom
We watch from Earth's surface, not its center	Earth's rotation shifts our viewpoint during the night	A small extra glimpse around the edge

The remaining 41% stays hidden from Earth at all times.

The far side is not the dark side

The hidden half is often called the "dark side of the Moon," but it gets just as much sunlight as the side we see. During a new Moon, when the near side looks dark to us, the far side is in full daylight.

It is only "dark" in the old sense of unknown. No one saw it until 1959, when the Soviet probe Luna 3 sent back the first photographs. They showed a surprise: the far side looks very different from the near side. It has far fewer of the dark, smooth plains (called maria) and is covered with many more craters. Scientists are still working out exactly why the two halves turned out so differently.

It happens all over the Solar System

The Moon is not unusual. Tidal locking is one of the most common outcomes in the Solar System. Most of the large moons of Jupiter and Saturn always show the same face to their planets.

Pluto and its largest moon, Charon, go one step further. They are locked to each other. Each always shows the same face to the other, so from one side of Pluto, Charon hangs in the same spot in the sky and never rises or sets.

So the next time you see the Moon, remember that its steady face is not stillness. It is the result of a long tug-of-war with Earth — one the Moon settled long ago, and one Earth is still slowly losing.

The Moon Is Slowly Leaving Earth — And It’s Changing Our Days

Constantine Kim — Tue, 01 Sep 2026 13:44:34 +0000

The Moon feels like one of the most permanent things in our sky. It has been orbiting Earth for billions of years, controlling the tides and lighting up our nights. But the Moon is actually moving away from us.

Every year, the Moon drifts roughly 3.8 centimeters farther from Earth. It sounds insignificant, but over astronomical timescales, the effect becomes much more interesting.

The reason is connected to Earth's rotation and ocean tides.

As the Earth rotates, its oceans bulge slightly because of the Moon's gravitational pull. That tidal bulge doesn't point exactly toward the Moon. Because Earth rotates faster than the Moon orbits, the bulge gets carried slightly ahead of the Moon.

The Moon's gravity pulls on this bulge, and that interaction transfers a tiny amount of Earth's rotational energy to the Moon. As a result, the Moon gains orbital energy and gradually moves into a higher orbit.

At the same time, Earth is losing rotational energy. This means Earth's rotation is very slowly slowing down, making our days longer.

Billions of years ago, a day on Earth was significantly shorter than it is today. In the distant future, Earth's rotation will continue to slow, although the process is complicated by other factors affecting our planet.

Interestingly, the Moon won't simply keep moving away forever. The system is evolving toward a state where Earth's rotation and the Moon's orbital motion would become synchronized. However, the Sun's future evolution will dramatically change the Earth-Moon system long before that theoretical equilibrium could be reached.

So the next time you look at the Moon, remember: it isn't sitting still.

It is slowly moving away from us — just a few centimeters at a time.

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