Got a second? Some physical constants seem more natural than others, both in derivation and in use. One range of measurement is often better suited by a particular choice of units. The definitions and conversions for common use are simple, practical, yet often arbitrary.

The orbital period of the earth, the year, makes a convenient unit for some measurements but not substantially quicker ones. A year also becomes unwieldy at longer time scales like those found in astronomy. Some degree of subdivision is thus necessary, above and below, and the choice should be both reasonable and practical.

Many kiloseconds have been spent mathturbating about the “secrets” of the Great Pyramid. However I believe its main “secret” is in plain sight. The obelisk celebrates a magnificent milestone in human achievement uniting mathematics, cosmology, and metrology. It recognizes humanity's standardization of the “second,” realizing the derivation in stone.

The standard adopted is the number of seconds in one year, PI * 10**7. The constant factor 86400 (24*60*60) is used to scale the time system downwards (to the seconds per year we still use) and upwards (to the precession cycle of the earth against the stellar “background”). The device models a hemisphere of earth with a scale half this factor (43200).

That definition establishes a chain of physical measurement systems, including today's metric and imperial systems. Once the time unit (second) is known, the length unit (meter) is derived as the pendulum length that produces a half-period of one second. The mass unit (gram) represents the mass of a metric volume of water. (The imperial system incorporates a conversion scale based on PI.)

Each side measures 440 Royal Cubits (R.C. = PI/6 meters). In an acoustic context 440 Hz (“concert A”) has a wavelength of PI/4 meters (20degC 343m/s). Hence the R.C. Scale can be interpreted as a musical, or logarithmic scale, based on the reciprocal of PI. In this manner problems may be transformed from one domain to another depending on where PI appears in either numerator or denominator. Simple constants such as Astronomical Units expressed in this system result in powerful, elegant mathematics.

It is mathematically suggestive – all mistakes being my own – this standardization scales mass into spatial dimensions using divisions of time, united by musical notation linking mathematics and gravitation..The obelisk acts as a giant slide rule with multiple scales, reinforcing metronomic standards we still use today. Consider this “pi in the sky” as real as the ancient wonder built to savor it.