Lunar Flow2026

Reading the year

• Earth through the vortexEarth rides its orbit through the middle of the loops, turning on its 23.44° tilt as it really does, shown fully lit so you can see it. Its place on the circle is the exact season. The moon's path loops around it counterclockwise, as it really does: one even loop each month, each flowing into the next, never ending.
• The sun is outsideThe sun glows at the outer edge. New moon swings outward toward it, and full moon swings inward toward the center, which stands for the night sky directly away from the sun, where the full moon lives.
• The moon at the centerIt shows the moon's true lit fraction for the day you are on, animating smoothly from new to full and back. It is held still at the angle it sits as it rises where you stand, so each place on Earth sees it turned its own way, with only the light moving across it. Tap it to see it large. Swipe across the moon along the way its light travels to move through the month; the first time, an arrow shows the way forward for where you stand.
• Go to any dayTap the line to jump to that moment. Anywhere else on the dial scrolls the page. Press and drag along the loops to move through time; the moon and Earth follow your finger, and there is always path ahead of you. Now brings you back. ▶ moves forward through time; ❚❚ stops.
• Day Night TideEach day is a small loop on the path, sunrise to sunrise, gold while the sun is up where you stand, swelling with the two daily high tides. Noon faces the sun.
• A year around youThe path shows nearly five months behind and five months ahead of the day you are on, with Earth exactly halfway. The two ends stop at the month labels directly across the dial: a clean edge arriving, a fade leaving. Days ahead are drawn a little softer. Each year the loops land about 11 days further back against the seasons.
• The 19-year returnThe faint lace behind the loops is a full cycle of the moon, nineteen years of its path laid over one another. A year holds about 12.37 moons, not a whole number, so each year the moons land about 11 days earlier against the seasons, and each layer of lace sits turned from the one before. The slips add up: after 19 years the moons have worked their way through the whole year and come back almost exactly where they began, because 235 moons last 6,939.69 days and 19 years last 6,939.60, about two hours apart. The twentieth year lands on the first, and the pattern starts again. Since 235 is 19 × 12 + 7, a calendar that keeps its months with the seasons adds seven extra months in every 19 years; the Hebrew and Chinese calendars do, and the Golden Number used to date Easter counts the same cycle. The two hours add up to a full day about every 219 years.

This moon

Harvest Moon

The metronome

Keeping time by the moon

• Before writingMarked bones and plaques may be the oldest moon records anywhere. The Lebombo bone from southern Africa, about 43,000 years old, carries 29 notches. The Abri Blanchard plaque from France, about 30,000 years old, and the Ishango bone from Central Africa, about 20,000 years old, are read by some as tallies of the moon's phases.
• Warren Field, ScotlandAbout 10,000 years ago, hunter-gatherers dug a line of twelve pits that follow the phases and months of the moon, aligned to the midwinter sunrise so the count could be corrected each year. It is the oldest lunar calendar yet found.
• Aboriginal AustraliaThe Yolngu of Arnhem Land have long tied the moon to the tides: as the moon rises full, it fills with water from the sea and the tides run high; as it empties, the tides fall. Knowledge carried in story for thousands of years, long before Newton explained why.
• The PacificThe Māori maramataka and the Hawaiian moon calendar give every night of the month its own name and its own work: when to plant, when to fish, when to rest. Both are still kept today, by growers, fishers and families.
• North AmericaThe moon names on this dial come from Algonquian and other Native peoples, who named each moon for what the land was doing. At Chimney Rock in Colorado, Ancestral Puebloans built a great house where the moon rises between two stone spires once every 18.6 years, at its northernmost swing.
• Calendars still runningThe Hebrew, Chinese and Hindu calendars follow the moon and add months to keep step with the seasons, on the same 19-year rhythm drawn on the dial. The Islamic calendar follows the moon alone, so its months move through all the seasons over about 33 years.

Eclipses

Seen from the side, the sun travels left to right and Earth spirals around its path once a year, December solstice at the top of each turn, with the moon spiraling around Earth. Eclipses happen only where the moon lines up with Earth and sun, marked on the path: gold rings for the sun, copper for the moon. They come in pairs about two weeks apart, twice a year, when the moon's tilted orbit crosses the line to the sun. Tap one to go there.

The moon from where you stand

• Everyone sees the same faceThe moon turns once on its axis for every trip around Earth, so the same side always faces us. Every person who has ever lived has looked at the same seas and craters.
• Everyone sees the same phaseThe phase is set by where the sun, Earth and moon are, not by where you stand. At any moment, a first quarter in Sydney is a first quarter in Reykjavík.
• What changes is the angleThe moon rises along the slant of your sky's equator, which leans by 90 degrees minus your latitude. Near the equator the moon rises lying on its side; toward the poles it stands upright. South of the equator it is upside down from the north, lit on the opposite side, which is why moons in southern art can look backward to northern eyes.
• What changes is the clockThe same full moon rises at different local times around the world, and from any one place moonrise comes about 50 minutes later each day, because the moon moves along its orbit while Earth turns.
• The seasons follow youThe dial's season labels flip south of the equator, where December brings summer. Near the equator they become simple month spans, since there is no true winter or summer there.