Schumann Pulse
The Moon / The interactive lab
Move through the light.
Change your point of view.
Surface: NASA / LROC · Schematic lighting
Ideal cycle · Not today’s Moon
of the visible disk sunlit
Sunlit area of the visible disk (%)
Approximate days through one ideal cycle
Waxing gibbous
An ideal 29.53-day cycle, from new Moon to new Moon. The day shown is approximate.
Choose an orientation
Illustrative views, not a local sky prediction.
What you are seeing
85.4% of the visible disk is directly sunlit at this point in the ideal cycle. This is an area fraction, not a brightness reading. The same fraction can occur on the waxing and waning parts of the cycle.
Why the light changes ↗Shadow detail is brightened to reveal the complete Moon. It is not a measurement of earthshine. No exact sky tilt, terrain shadows or libration are modelled.
This static example shows a waxing gibbous Moon. Enable JavaScript to explore the cycle; the explanations below remain available.
01 / Phases
Sunlight falls on roughly half of the Moon. As the Moon travels around Earth, a different amount of that sunlit half faces us. Waxing means the visible lit part is growing; waning means it is shrinking. The phases are not caused by Earth’s shadow.
Understand the eight Moon phases ↗02 / Illumination
First and last quarter show a half-lit disk. “Quarter” refers to the Moon’s progress through the cycle. A 50% illuminated disk is not a promise of half the full Moon’s brightness: surface scattering and viewing conditions also matter.
What lights the faint side? ↗03 / Hemispheres
People across Earth see essentially the same phase at the same instant. Its orientation against the horizon can differ. Our paired examples rotate the whole view, including its surface features, without changing the illuminated area.
Compare hemispheres and seasons ↗Teaching model reviewed 22 October 2026
This laboratory explores relationships. For the current phase and calendar dates, use Moon today, which has a separate astronomical calculation.
We move uniformly through an ideal circular cycle. If θ runs from 0° at new Moon to 360° at the next new Moon, the illuminated fraction is k = (1 − cos θ) / 2. Approximate model day is θ / 360 × 29.53059. The graph’s scales stay fixed from 0 to 100% and one complete model cycle.
Real lunar motion is not uniform, and individual lunations vary in length. The slider is not a date selector, an eclipse model or an event-time prediction. At new and full alignments this model gives exactly 0% and 100%; real geometry can differ.
The southern illustration rotates the northern view by 180°. This is an explanatory comparison, not a universal correction for every photograph. The local angle also depends on latitude, time and viewing direction. Near the equator, the crescent may appear strongly tilted. The same phase does not abruptly flip when someone crosses the equator.
The surface texture stays fixed apart from this rotation. Libration, terrain shadows and a physically calibrated brightness response are not included. Shadow detail is brightened to reveal the complete Moon, with a gentle illustrative falloff toward the night side. This display choice is not calculated earthshine and does not change the geometric sunlit fraction.
Background: NASA’s Moon phases (opens in a new tab) and NASA’s Moon viewing questions (opens in a new tab). Our Moon guide connects the detailed explanations.
Surface: NASA SVS CGI Moon Kit (opens in a new tab), Ernie Wright / NASA Scientific Visualization Studio; LRO / LROC WAC camera-team data assembled by Arizona State University. We use an orthographic texture projection with a geometric illumination mask. This is an illustration, not a live photograph or NASA endorsement. The star field is original AI-assisted artwork, not a sky map.
From the model to today
See the current phase, lunar age and next full Moon, with a monthly calendar in your time zone.
See Moon todayYour own perspective
Schumann Pulse brings lunar context together with your mood, optional energy and sleep-quality records. Revisit available personal comparisons as enough suitable history grows.
Explore what you can track ↗Coming soon for iPhone. History and personal comparisons live in the app.
Continue exploring: Schumann resonance lab ↗ · Space-weather lab ↗