Metric system

The process of standardizing units throughout the world is often called metrication. This has happened in the game world slightly differently from the real world. Some units correspond close enough for a direct translation, but not all.

Length
One common size for class M planets in God's experiment is a circumference close to 4 * 107 m. Notice how round this number is. This is not a coincidence. In fact, it's fairly common for planets adopting an international system of units and positional numerals to have a length unit close to the planet's diameter divided by a "nice round number" in whatever number base dominates trade.

In the game world, as in the real world, before metrication, people measured distances in anthropic units, which were related to lengths of parts of the body, a stride, or how far the local draft animal could pull a plow at a time. One unit called the "foot", based on the length of a human's shoe or on the length between nodes of bamboo, was not widely used in trade because the anatomy of some races (notably polis) had no direct counterpart, nor did bamboo grow everywhere. The "span", which later became the "link", was more popular because full-size land-based races tended to have fairly uniform hands. As industrialization took hold, units that can be translated as links, chains, and furlongs emerged. Different countries used different definitions for these until the units were reformulated in terms of a unit translated "meter". As on Earth, the game world meter was defined first as 1/107 times the distance from the pole to the equator and later in terms of some other physical constant.

Metrication fixed the new link as one-fifth of a meter. Sizes of wagon wheels were standardized at multiples of a link in circumference, and land was resurveyed in the new units.
 * rod = 25 links = 5 m
 * chain = 4 rods = 20 m
 * furlong = 10 chains = 200 m. This originated in the length that a team of draft animals could pull a plow in one session.
 * mile = 8 furlongs = 1600 m

Area

 * rood, decare, dunam/donum, stremma, or mål = 1 rod * 1 furlong = 1000 m2 = 0.1 hectare. In more fertile areas, landlords leased farmland to peasants (tenant farmers) by the rood. In less fertile areas, the size of a standard field was based on anticipated yield.
 * acre or feddan = 1 chain * 1 furlong = 4000 m2 = 0.4 hectares
 * oxgang = 15 acres

There was some minor fallout over who owned what land immediately after metrication.

DX Town uses a "binary acre" of 4096 m^2, analogous to the "binary kilobyte".

Time
God divides the life cycle of an experiment into seven periods: six of building and one of resting. This rest period coincides with the era of sapient creatures' activity. Thus God uses the week as an analogy to explain rest. The day and year of the game world match those of the real world. Periods shorter than a day have yet to be investigated, but the period of a pendulum with a period of two seconds is very close to 1 m.