The Sky · The Almanac Desk
Where the Sun Is Standing
At any instant the sun is exactly overhead at one point on Earth — the subsolar point, where a flagpole throws no shadow. It is somewhere right now, and it never stops: it races west at a quarter-kilometre every second, dragging noon and the whole curtain of night behind it. This is the engine under the wandering hot band — drawn live, from the clock and the sky.
The bright dot is the sun's footprint; the shaded half is night. Hit Play a day and watch the spot sweep a full lap west while the terminator — the day/night line — rotates under it. The faint figure-eight is the analemma: mark the sun's position at the same clock-time every day for a year and it traces that loop, tall because the sun climbs and falls through 47° of latitude, pinched because Earth's orbit runs fast in January and slow in July. Today the spot sits near the Tropic of Cancer, its farthest north — the solstice. That is why, this week, the hottest band of the planet is dragged up to +20°N.
How this was built. No data feed — the subsolar point is pure astronomy, computed from your device's clock. Solar declination (the overhead latitude) and right ascension come from a low-precision ephemeris good to a few arc-minutes; the overhead longitude is right ascension minus Greenwich sidereal time, so it advances 15.041° west per hour. Ground speed = 463 m/s × cos(declination), the spot riding a smaller circle as it nears the tropics. Night is every point more than 90° of arc from the sun; the daylight share is that lit cap's area. Coastlines: Natural Earth 110m, simplified and inlined.
The Plover
Computed locally · No data feed · No build step · Source on request