By The Metric Maven

The late Isaac Asimov (1920-1992) was a great promoter of the metric system. In the early 1960s Dr. Asimov wrote an essay about the metric system entitled Pre-Fixing It Up. The essay appears to have been inspired by the official addition of new metric prefixes in 1960. Some of the essay shows its age, but Asimov makes an observation about the metric system which still seems lost on most people:

All other sets of measurements with which I am acquainted use separate names for each unit involving a particular type of quantity. In distance, we ourselves have miles, feet, inches, rods, furlongs, and so on. In volume, we have pecks, bushels, pints, drams. In weight, we have ounces, pounds, tons, grains. It is like the Eskimos, who are supposed to have I don’t know how many words for snow, a different word for it when it is falling or when it is lying there, when it is loose or packed, wet or dry, new-fallen or old-fallen, and so on.

We ourselves see the advantage in using adjective-noun combinations. We then have the noun as a general term for all kinds of snow and the adjective describing the specific variety: wet snow, dry snow, hard snow, soft snow, and so on. What’s the advantage? First we see a generalization we did not see before. Second, we can use the same adjectives for other nouns, so that we can have hard rock, hard bread, hard heart, and consequently see a new generalization, that of hardness.

The metric system is the only system of measurement which, to my knowledge, has advanced to this stage.

Asimov makes a point in the 1960s which appears to be completely absent from contemporary metric advocacy discussions. The metric prefixes themselves provide an intuitive set of relative magnitudes, expressed in literary form. People do not generally realize this because of the dismal manner in which “scientific journalists” present weights and measures in the media. I wrote a guest blog on the penetration of metric prefixes into our culture, but they only are vaguely understood, and their monotonic relationship is not clearly articulated.

There is only one technical area with which the public deals that has slowly introduced each metric prefix such that people have an idea of their relative magnitudes. That area is computers. In the early days of computing, a computer such as the Timex Sinclair 1000 came with about 2K of memory. That is, it has approximately 2 Kilobytes of memory. Memory escalation had begun and the Commodore 64 had—well—64 Kilobytes of random access memory (RAM). Soon computers would have Megabytes of RAM. The computer I’m currently using to write this essay has 2 Gigabytes of RAM. The use of the metric prefixes to describe computer memory has been a slight kludge as computer memory is in multiples of two. A Kilobyte is actually 1024 bytes instead of 1000 bytes as the metric prefix implies. There is an attempt to introduce binary name versions called the kibi, mebi, gibi and so on, which correspond to the actual metric prefixes, but exactly describe the number of bytes.

Metric prefixes have long been used to approximately count up all the ones and zeros available in computer memory, or on a disk drive. The RAM of a typical computer has increased from Kilobytes, to Megabytes, to Gigabytes. One knows that a file which is in the Kilobyte range is easily emailed. A file which is 1-2 Megabytes is pushing the email envelope a bit, and 10 Megabytes is a really large file to attach to an email. One would not even consider sending a 1 Gigabyte file, it is immediately apparent from the prefix that it is untenable.

As Asimov points out, the metric prefixes act like adjectives. Email attachment file sizes can be seen as small (Kilobytes), large (under 4 Megabytes), and too large (Gigabytes).

Computers use disk drives to store digital files. 5 1/4 inch floppy drives increased from 360 kilobytes to 1.2 megabytes. The 5 1/4 inch floppy drive was replaced by the 90 mm (~3.5″) floppy which held about 1.44 megabytes. Hard disk drives (HDD) with many Megabytes of space were introduced to the consumer. As time went on, Gigabyte sized hard drives were introduced. When compared with Megabyte sized drives, they seemed almost limitless in size. Currently 1-2 Terabyte drives are commonly available. The Greek roots of the prefixes are descriptive. Megas means “great,” gigas is “giant” and terras is “monster.” Indeed a Terabyte drive is monstrous in size—at least as of this writing.

The problem is that only in the computer industry have we been inculturated with the metric prefixes. As I pointed out in an earlier essay, I was not pleased that the producers of Cosmos chose to use Kilometers, light-years and astronomical units to describe celestial distances. Dr. Asimov encouraged metric usage in astronomy over forty years ago. He begins with the meter, then describes the Kilometer in terms of distances in Manhattan, “…a kilometer would represent 12 1/2 city blocks.” He moves on to the Megameter:

This is a convenient unit for planetary measurements. The air distance from Boston, Massachusetts, to San Francisco, California is just about 4 1/3 megameters. The diameter of the earth is 12 3/4 megameters and the circumference of the earth is about 40 megameters. And finally, the moon is 380 megameters from the earth.

Passing on to the gigameter, ….this comes in handy for the nearer portions of the solar system. Venus at its closest is 42 gigameters away and Mars can approach us as closely as 58 megameters. The sun is 145 gigameters from the earth and Jupiter at its closest, is 640 gigameters distant; at its farthest, 930 gigameters away.

There is no need for Asimov to have qualified the Gigameter as only being “handy for the nearer portions of the solar system.” This is a pre-Naughtin’s Laws view of the metric system. The Gigameter is completely useful for describing the distance to Pluto and the position of the Voyager 1 and 2 spacecraft. Asimov continues:

Finally, by stretching to the limit of the newly extended metric system, we have the terameter…this will allow us to embrace the entire solar system. The extreme of Pluto’s orbit, for instance is not quite 12 terameters.

Two factors that Asimov did not foresee was that Neil deGrasse Tyson would “kill Pluto” and the introduction of Naughtin’s 3rd Law: Don’t Change Measures in Midstream. The extreme of Pluto’s orbit quoted in Asimov’s essay is 12 000 Gigameters. If the Australian construction industry can handle this large of a number in millimeters, I’m sure astronomers can muddle through with it in Gigameters.

One cannot fault Asimov for not pushing matters further. It would not be until 1991 when enough metric prefixes would be added to encompass the entire observable universe. Asimov does realize the limitations of light-years and parsecs (3.2 light years):

Even these nonmetric units err on the small side. If one were to draw a sphere about the solar system with a radius of one parsec, not a single known star would be found within that sphere. The nearest stars, those of the Alpha Centauri system, are about 1.3 parsecs away.

The current version of the metric system has no problem describing the macroscopic universe. Here is a table from an earlier essay on the subject:

The overall point is that if the metric system was completely adopted in the US without dilly-dallying, we would use the metric system, and its appropriate prefixes, to describe all important scientific discoveries and ideas. Children would grow up memorizing metric prefixes (without the prefix cluster about unity) as earlier children committed multiplication tables to memory. This exclusive metric ecosystem would soon provide a reinforcing context for the relative sizes of the metric prefixes, and make the public as well as people in technical vocations, much more numerate. Astronomy texts would use metric to describe distances, and only mention light years as a gee-whiz! metaphorical supplement to actual measurement units.

Dr. Asimov died in 1992, just after the new set of metric units from yocto to Yotta were adopted. They describe the world which engineering and science encompass at this time. It is sad that the gentle doctor has been gone for over 20 years, and we are no closer to adopting metric units for everyday engineering and science, let alone in our public news media. Dr. Asimov expressed his frustration that no one was listening to his appeals for the metric in the early 1960s in his essay Forget It!. The US has continued to ignore the metric system for over 50 years since that essay first appeared. Will metric adoption take 200-300 more years to occur in the US? I don’t know. What I do know is I don’t have time to wait around that long, and neither did Dr. Asimov.

Isaac Asimov’s birthday was on January 2.

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