How Earth Is Lit: Two Views
Compare daylight on an azimuthal equidistant (“flat Earth”) map with a local Sun and on a globe with a distant Sun.
Follow the daylight boundary
Two cycles show daylight alone, followed by two with a local spotlight. Then daylight loops continuously; the Sun toggle is yours to control.
Explore the proposed spotlight
Dashed amber circle = a downward, circular beam. Sun icon marks its position over the tropics; height and beam size are illustrative.
How this preview is calculated
North-pole-centered azimuthal equidistant projection. Each pixel is converted back to latitude and longitude. Daylight is computed from sin(latitude) sin(declination) + cos(latitude) cos(declination) cos(longitude − subsolar longitude) > 0. The boundary is the geometric horizon, without atmospheric refraction, twilight, terrain or the Sun's finite disk.
Seasonal declination varies smoothly between ±23.44°. Daily rotation and seasonal progression are accelerated independently for clarity: this is a seasonal illustration, not a continuous calendar-year ephemeris. Each season holds briefly while the daylight pattern revolves. In December, locations south of the Antarctic Circle stay in daylight throughout the rotation. An AE map greatly enlarges southern areas; screen area does not represent physical area.
The globe and disk share the same solar declination and subsolar longitude. Earth spins about its tilted axis; the globe camera follows the seasonal Sun direction, keeping sunlight arriving from the right. This makes the illuminated hemisphere easy to compare throughout the year. The small Sun symbol indicates direction; its size and distance are not to scale.
The shading uses standard spherical solar geometry, consistent with observed sunrise and sunset patterns; this animation is an illustration rather than an independent measurement dataset. The Sun overlay tests a conventional downward circular spotlight, not every imaginable custom beam.
Map: Natural Earth (public domain). Geometry: NOAA solar-position equations.