Any clock that depends on observing the brightness or darkness of visual sensations from the Sun is called a solar clock. The most basic solar clock is just squinting at the Sun. But historically, complex sundials have been widely used for solar clocks as well. By the foregoing definition, all solar clocks are at least partly objectified from black and white sensations. So any solar clock , may be characterized by its spin. And if is part of a reference frame, then it can be used to establish the phase for any other particle as
When this phase is used to make relative descriptions of terrestrial events, it can be understood as if an event occurs during the day, or if an event occurs at night. One cycle of a solar clock may be called a solar day, or twenty-four hours, or a nychthemeron. But usually we just call it a day. Solar clocks are always available to provide this semantic anchor for interpreting the phase because seeing the Sun is assumed to be a reference sensation for EthnoPhysics.
Ideas about time are based on solar sensations because the Sun is such a prominent and lofty feature of human consciousness. But the Sun does not have a celestial monopoly, and other clocks may be defined from moons, planets and stars. Sometimes it is more appropriate to tell time by these other clocks, for example astronomers make extensive use of variable stars But telling the time by a non-solar clock might be quite meaningless for use with events here on Earth. So making a unified description of celestial and terrestrial events requires some additional systematic connection between clocks. Astronomers bridge the logical gap by measuring stellar characteristics and comparing their observations with nuclear processes seen here on Earth. This is yet another example of how physics depends on recognizing recurrent patterns. So let’s take a closer look at these repeated waves.