Earth Clock

Earth Clock clearly demonstrates the 3 main planetary, astronomical rhythms that are the most basic units of a clock & calendar:

The Solar Day is the 24 hour period of time it takes for the Earth with a time zone-spanning hour hand (marking your location on the globe) to make a complete rotation relative to the Sun fixed at noon at the top of the dial. Note the circle of illumination, where night meets day, and if you watch over the course of a year, you will see it rhythmically tilt above and below the Earth’s spin axis, the north pole. The 4 corners of a solar day are clearly visible at all times: midnight, Sun rise, noon & Sun set.

The lunar Month is the approximately 29.5 day period of time it takes for the Moon to orbit the Earth, going through its phases relative to the Sun, fixed at noon at the top of the dial. The 4 corners of a lunar month are new Moon, waxing 1/2 Moon, full Moon & waning 1/2 Moon.

The Seasonal Year of 365.2425 days is the average amount of time it takes for the Earth to orbit the Sun, or for the Sun to apparently circle the ecliptic, starting and ending at the ascending or spring equinoctial node, which marks 0º right ascension on the celestial coordinate system. With Earth Clock, the Sun is always fixed at noon at the top of the dial, so the stars marking the celestial sphere (and the signs of the zodiac) appear to rotate around the Earth once every seasonal year. There are 4 corners of a seasonal year: spring equinox, summer solstice, fall equinox & winter solstice. The progression of the Sun along the ecliptic is translated into a progression of the year indicator along the 365.2425 solar day-blocks marked on the calendar band.