Watch an orbital overview beside an enlarged rotating Earth. A moving surface marker crosses the terminator. Sidereal rotations and solar days differ because Earth moves along its orbit while spinning; the local solar-time dial and sunlight elevation follow the same geometry.
• A real-time 3D scene with 5 inspectable parts (Sun–Earth orbital overview, Rotating enlarged Earth, Surface observer, Sun direction and terminator, Solar-time clock), with home view, focus-selected-part, auto-rotate, expand, instrument-cover and hide-labels scene tools, plus a model response curve beneath the scene. • Experiment controls: Initial elapsed solar days (0-365 days); Observer latitude (-80-80 °); Observer longitude (-180-180 °); Solar days per animation second (0.01-0.5 d/s); pause/resume, 0.1 s and 1 s single-step buttons, four playback speeds and a restart button. • Live readouts: Elapsed solar days; Sidereal rotations; Solar cycles; Solar elevation; Orbital progress; Local solar time. • A Geometry & measurements tab with a parameter-comparison chart, a live-measurements chart, the model equations and snapshot readouts. • An Experiments tab with 3 guided presets (One solar day; Opposite longitude; High latitude) and a Model verification bench that runs independent fresh models, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset and a written model-scope statement linking to a technical reference.
Circular, zero-obliquity model: Nsidereal=t(1+1/365.25636) Nsolar=t; orbital angle=2πt/365.25636 Hour angle=spin−orbit+longitude Solar elevation=asin(cos latitude cos hourAngle) Sidereal day≈24/(1+1/365.25636)=23.9345 hours
Zero obliquity and circular orbit deliberately isolate the sidereal/solar distinction; no seasons, equation of time, refraction, time zones or leap seconds. Elapsed days are uniform 24-hour model solar days. Sun and globe sizes and distances are illustrative.
No. Earth’s orbital progress requires an extra spin angle to face the Sun again.
No. Obliquity is zero here to isolate rotation; the separate Seasons lab includes tilt.
Zero obliquity and circular orbit deliberately isolate the sidereal/solar distinction; no seasons, equation of time, refraction, time zones or leap seconds. Elapsed days are uniform 24-hour model solar days. Sun and globe sizes and distances are illustrative.