## 20120707

### New metric units

I received the following from James Strom, with my comments added:
Hi! I like to dabble in things like you have at your decimal time site. Decimal time is definitely an idea who's time has come.
Whose time has come?  I'd say it already came and went two centuries ago!
But for it to be practical it must be compatible with any metric system in use. If the second were changed by anything other than by a power of ten then the cost of conversion would be enormous. The definitions of a joule, newton, ampere, volt, etc. would all have to be changed as well. Can you imagine having to multiply your wattage by 0.864 cubed to arrive at the new watts? A simple way around that is to simply keep the second either the same or 10 or times smaller. I would recommend the latter so as to allow a second to be equal to 1/864th of a milliday and for other reasons.
I agree that the metric system (SI) is a serious impediment to introducing new time units.  Redefining the second would be a practically impossible undertaking, regardless of whether it's by a power of ten.  In fact, with today's technology it's just about as easy to convert decimally as otherwise.  And you cannot simply change unit values while keeping the same names, or nobody would ever know if you were talking about the old or new units.  Remember that everything in the world for hundreds of years has been recorded using essentially the same second.  Likewise for other units, although not for as long.  Creating all new units with the same names, even if they're a factor of 10 different, would create chaos.
I have noticed that if Greenwich is used as the prime meridian then 10 time zones can be created which fit very neatly with the continents. So forget Swatch's idea.
You apparently mean Swatch eliminating time zones.  You do not say why we should favor 10 time zones over one, or 24.  We may as well reform everything at once.  Business today is international.  So is my family.  It seems to me that time zones one-tenth day (2.4 hours) wide lack the advantages of smaller one-hour zones, while being only halfway to a single one for the world.
Any modification of our current system should have as a high priority ease of convertibility. The system described below has that in mind. In fact, it could be used by anyone right now without any trouble.
There is nothing that is as easy to convert as no change at all.  You need to have major advantages to outweigh the disadvantage of any conversion, no matter how easy it might be. And I don't really think that your proposal would be as easy as you claim for those who are currently using these units.
It won't be necessary for any international organization to get everyone else to agree to the change for it to work.
Who would use it, then?
It also assumes that lower case letters will someday be eliminated.
Why?  That would eliminate half the available symbols for units and prefixes.  It would also require everyone on the Internet to SHOUT all the time.
I've devised a modification of the current metric system that I think would be simpler, more intuitive, and easy to convert to. It would be similar to the change from the old cgs system (centimeter-gram-second) to the mks system (meter-kilogram-second).
These two systems used different names for nonequivalent units.  It was also a big pain in the ass to change, and not everyone has, yet.
As it is now the basic unit of mass requires a prefix (kilo) and doesn't correspond with weight.
The kilogramme was originally defined as a unit of weight.  The definitions of mass and weight were separated after it was realized that an object's mass is relatively constant, but it's weight is not.  My sisters in Colorado gain weight every time they come to visit me on the coast, but their masses remain the same.  (Unless my Mom is cooking.)  Scales do not actually measure mass, but the force of gravity acting on a particular mass.  However, for everyday use we can use our weight to approximate our mass.  To those relatively few professionals who have to use units of force to measure weights, it is advantageous that mass and weight have different values, lest they get confused.
The unit of density is, unlike almost all other measurement systems, is not even close to that of water but, in fact, less than that of air. This makes it difficult to visualize them.
The SI unit of density is kg/m3.  Water is 1000 kg/m3, or 1 t/m3 = 1 g/cm3 = g/ml.  I have no problem visualizing a cubic meter of water, or of a milliliter (cc).
On the other hand, if a system were devised that made the unit of acceleration close to the force of gravity on earth then it would be easy to picture it. Also, weight would become almost synonymous with mass. This would make it easy to imagine force in terms of these units. And if the unit of density were the same as that of water then there would be the obvious benefits.
I don't have a problem "picturing" these things, nor do I see how that is necessary.  I already weigh myself in pounds or kg, not 780 newtons.  I imagine newtons only when measuring small things in a lab.  (Which I have not done in decades.)  The benefits are not obvious to me.
This is what I propose:
1) The new unit of mass would be called a ton but would have the same mass as a kilogram.
We already have several different ton units causing confusion, and you want to add one that is not even close?
2) The "new" meter would be equal to one tenth of an "old" meter or a decimeter.
Again, I don't see the benefit of changing the value by an order of magnitude.
3) The day would be divided into 1,000 minutes. Each minute, in turn, would be divided into 864 seconds. Thus the "new" second would be equivalent to one tenth of an "old" second.
A compromise that has all the problems of both, and the benefits of neither!

I won't go through the rest, since I am not interested in changing the metric system.  That ship sailed a long time ago.  It took a lot of time and trouble to get the entire world to accept the current metric system, and now that it's done, there is no advantage to massively change it now, even if it's not perfect.  We have discussed these issues ad nauseum on this site in the past.
4) The ampere would remain the same and would be defined as the amount of current that would produce a force of 2X10^-8 Newtons between two wires, etc., in terms of the new units. In other words; the ampere would be 1/10,000th of the value that it have if it were defined by the basic three units alone. That's an improvement over the current system that requires division by the square root of ten million.
5) The unit of angle would be 1/1,000th of a circumference. This would align it with the units of time. The earth, in relation to the sun, would rotate one degree per minute.
6) The unit of temperature would be defined as 1/1,000th of the triple point of water. A celsius-like system could be used as well so that water would freeze at 0 and absolute zero would be -1000.
7) The unit for amount of substance would not change except for its name. It shall be called a quant instead of a mole and be represented by a Q instead of mol.
8) The unit of luminosity would be equal to one joule per second per steradian in terms of the new units and be renamed the young (after the scientist, of course).
Each of the units shall be represented by one letter only without regard to upper or lower case status.
The prefixes shall follow this rule as well.
Thus there will be 26 common units and a like number of prefixes.
Ratio refers to the ratio of the size of the "new" units to that of the "old" ones in the mks system.

Unit       Symbol     Quantity          Formula      Ratio

Ton                T       Mass                     T            1
Meter             M      Length                  M          0.1
Are                R       Area                 M^2        0.01
Liter               L       Volume             M^3       0.001
Second           S       Time                    S          0.1
Hertz              Z       Frequency          1/S           10
Einstein          E       Velocity              M/S            1
Gal                 G       Acceleration   M/S^2          10
Bole                B       Momentum     T*M/S           1
Newton           N       Force         T*M/S^2         10
Planck            P        Action         T*M^2/S        0.1
Joule              J        Energy    T*M^2/S^2           1
Ampere          A       Current                  A            1
Coulomb         C       Charge              A*S         0.1
Weber            W      Flux                    J/A           1
Volt                V       Potential              J/C         10
Henry             H       Inductance          W/A          1
Farad             F       Capacitance         C/V      0.01
Siemens         S       Conductance        A/V        0.1
Ohm               O      Resistance           V/A         10
Gauss             U       Strength             A/M         10
Maxwell          X       Intensity             V/M        100
Degree           D       Angle                     D       0.36
Kelvin             K       Temperature           K  0.27316
Quant             Q      Amount                   Q           1
Young             Y      Luminosity               Y     6,830

Symbol  Prefix  Multiple

V                      10^33
W                     10^30
X                      10^27
Y          Yotta     10^24
Z          Zetta     10^21
E            Exa     10^18
P           Peta     10^15
T          Tera      10^12
G          Giga       10^9
M         Mega      10^6
K            Kilo       10^3
H         Hecto       10^2
D          Deka       10^1
S           Deci      10^-1
C          Centi      10^-2
L           Milli       10^-3
U         Micro      10^-6
N          Nano      10^-9
B           Pico     10^-12
F        Femto     10^-15
A           Atto     10^-18
O         Zepto     10^-21
J          Yocto     10^-24
Q                      10^-27
I                       10^-30
R                      10^-33

This system is meant to work with decimal time, a reformed calendar, and the eventual elimination of lower case letters.
But that is the subject of another email.
(Don't worry about copyright or anything. I don't care who gets credit for what. I only bring this up because while googling your name I found some idiot who was trying to take credit for coming up with an obvious idea that dated back to the French Revolution. There's all sorts out there.)
MJD 56115.995

1. I am a bit more optimistic about the opportunity to transform our timekeeping system. Two centuries ago a change to decimal time would have required the junking of most of the very expensive clocks that were then in use. Today, one can, for a small sum, alter our clocks to whatever we please. There are plenty of apps for that. So now, I think, is the time for changing time. I will agree that the current metric system (SI) can be an impediment to introducing new time units, but not necessarily so. For instance, we could divide the day into 100 units, or centidays, without having to change the length of the second. We could simply say that there are 864 seconds to the centiday, or whatever term you would like for 1/100th of a day. A clock wouldn't display time in seconds but they would still be used for physics, electricity, etc. We could thus have a version of decimal time without having to alter SI in the least.
I doubt that if unit values were changed it would result in chaos. Do not some advocates of decimal time use decimal hours, minutes, and seconds? This doesn't seem to produce a lot of confusion. All you have to do is prefix the new unit with a 'd' and the problem is solved. And once decimal time became the norm then even that wouldn't be necessary.
When I wrote that we should forget Swatch's idea I was referring to their using Biel time (CET). I should have been clearer. I think using UTC, as we currently do, as the base time is better, particularly because of the neat time zones that it produces. Time zones, in my opinion, are a necessity. Having the date change in the middle of the day would create a number of problems, to say the least. This is why, for example, astronomers started the day at noon when using the Julian date when they could just as easily stuck with midnight. They didn't want their observing sessions cut in half by a date change.
The reason I favor 10 time zones ought to be obvious; we would be using decimal time. A single time zone just wouldn't be practical for common, everyday use. How would ordinary people deal with it changing from Monday to Tuesday right after lunch? I don't think that would go over so well.
Although the elimination of lower case letters would entail the loss of 26 symbols that can be used for prefixes I don't think that would be much of a burden. As it now stands, the use of two types of letters to represent the same thing serves little purpose other than to let us know which words are proper names and where the beginning of sentence is. Why complicate things by doubling the number of symbols we use to transmit one bit of information per sentence that we already knew anyhow?

1. "I doubt that if unit values were changed it would result in chaos. Do not some advocates of decimal time use decimal hours, minutes, and seconds?"

I don't know anybody using those units today. Hardly anybody has even heard of decimal time. Most people using decimal time are scientists and computer programmers, and they mainly use fractional days and SI seconds.

2. "astronomers started the day at noon when using the Julian date when they could just as easily stuck with midnight. They didn't want their observing sessions cut in half by a date change."

Actually, they started the day at noon because there is no way to tell when it's midnight by observation. Astronomers used to spend a lot of time observing the sun transiting the meridian, which was how they knew when to change the date. See Wikipedia. But that doesn't change your point. No, so-called "Biel Mean Time" is a misnomer, and UT is a long-existing standard. The question is, how many time zones should there be. Again, 2.4 hours is very wide. What about 20 zones?

3. "Although the elimination of lower case letters would entail the loss of 26 symbols that can be used for prefixes I don't think that would be much of a burden."

I'm not sure why we have two cases, but they're popular in many languages, so I don't think that people will give them up easily. They do serve some purposes, like distinguishing proper nouns and the beginning of sentences. German uses them even more than English. But if we were to only use one, I would think that lower case would be preferred. There are far more small letters used than big ones. Also, prefix symbols are not abbreviations, so there's no reason why both alphabets cannot be used for them.

4. "I am a bit more optimistic about the opportunity to transform our timekeeping system."

You still have not explained WHY people would prefer decimal time over standard time. Our current system is used by everyone, and the 24-hour day has been around for thousands of years. It's not like when the metric system was introduced, and there were hundreds of different units for length, weight, etc. Never mind that there are millions of clocks and watches being used which CANNOT be changed. You need a compelling reason why they should be.

2. Using upper case letters only looks like shouting in the proper context. It otherwise just looks neater and easier to read. Scroll up to the top of this page. DECIMAL TIME doesn't seem to be shouting.
I advocate changing the metric for the same reason it had been changed earlier. The base units in the previous cgs system were just too difficult to visualize. This is important. Their unit of force, the dyne, was equal to about the weight of a milligram. This was way too small. You can imagine a multiple of it, such as a megadyne, but that doesn't do any good. When doing calculations in your head it becomes imperative that the base units be easy to visualize. Suppose that instead of the meter the French chose the kilometer as their basic unit of length. Now try picturing what their unit of pressure would be like. Let's see, the force of a kilogram being accelerated at 1 km per second per second on the surface of a kilometer squared. You would probably have to pull out a pencil and paper to even figure out if it's anything like air pressure.
When you visualize a cubic meter of water you're not visualizing all the base units of SI. Try visualizing something with the volume of a cubic meter but the mass of a kilogram. And, also, at a place where the gravity is one-tenth that of earth. It's not so easy then, is it?
This is why, when they changed from cgs, they didn't take the simple route of the meter-ton-second system. They wouldn't have had to attach a prefix to the unit of mass and the unit of density could have stayed the same as that of water. But the ton is just too large. We can't visualize what a weight (or mass) like that is like. Have you ever lifted a ton? The same sort of problem would occur if they went to a simple meter-gram-second system. Now they're dealing with a density 1/1,000,000th that of water. Not to mention that the units of force, energy, etc. are still too small.
But the compromise they achieved with SI could have been done better. This is why I proposed these changes. Conversion should be even easier than changing the time system. That's why we have the meter but are still stuck with Babylonian time. And changing from the imperial system to the metric would have been much more difficult than moving some decimal points around as with the cgs/mks conversion. So why not? If something is worth doing it is worth doing well.

1. But WHY is it worth doing at all? Converting to decimal time would be hard enough, without messing with the entire metric system. To be honest, I don't have any interest in discussing metric reform.