## Redefine the metric system

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zenten
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### Redefine the metric system

Lets suppose you were given the power to redefine the metric system to make the values fit better. What would you change? Assume everything is called the same, and you still have the same prefixes with the same meaning, you just change the actual value for metres, seconds, grams, etc.

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the speed of light would be exactly 3*10^8 m/s. I can't be bothered to remember all of those digits.

evilbeanfiend
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Shadowfish wrote:the speed of light would be exactly 1. I can't be bothered to remember all of those digits.

fixed
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e946
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1 meter per second?

That's one long-ass meter.

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Or a short ass-second.
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hyperion
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Well changing c (299792458 m/s) to exactly 3*10^8 m/s wouldn't be that bad. A metre would only change by a few millimetres.

EDIT: A new metre would be 0.99930819333... old metres, so there would be no change to normal people.
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bippy
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e946 wrote:1 meter per second?

That's one long-ass meter.

In all fairness he did kill the units so we can't be sure if he was talking m/s or delicious hot dogs/year.

CellBlock
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I'd use the FFF system, where length is measured in Furlongs, mass in Firkins (of water), and time in Fortnights.

The speed of light is approximately 1.8 megafurlongs per microfortnight.

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e946 wrote:1 meter per second?

That's one long-ass meter.

cop: "I caught you going 8.94698959 Ã— 10^-8 in a 5.96465972 Ã— 10^-8 zone. "

bonder
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I'd take a tip from the high energy physicists: redefine so that c = h = h_bar = mu_naught = epsilon_naught = pi = G =1.

High energy physicists actually do things like this (I admit I carried it a bit to the extreme) but then at the end of their calculations, they use dimensional analysis to find out how many c's and h_bar's etc. that they need for the correct answer.

Once, a high energy physics professor was doing a calculation in class and in order to get the right answer in the end said "and we can see through dimensional analysis, we need a 2*pi in here"....
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gmalivuk
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CellBlock wrote:I'd use the FFF system, where length is measured in Furlongs, mass in Firkins (of water), and time in Fortnights.

The speed of light is approximately 1.8 megafurlongs per microfortnight.

If you're actually using FFF, that should be 1.8 tera furlongs per fortnight. Otherwise, you're talking an FFÂµF system or something.

Planck units are not useful for everyday applications, but we could adjust them by orders of magnitude. For instance, the Pgram (Planck gram) could be 10^6 Planck masses, or about 21.7 old grams. The Psecond becomes 10^44 Planck times, or about 5 old seconds. Then, while the physical constants are no longer all equal to 1, they are all integer powers of ten.
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shill
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I was also thinking of using powers of ten of Planck units, but I wouldn't be so happy about the idea of decreasing the granularity of the second.

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GMontag
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shill wrote:I was also thinking of using powers of ten of Planck units, but I wouldn't be so happy about the idea of decreasing the granularity of the second.

So use 10^43 and double the granularity instead!

evilbeanfiend
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shill wrote:I was also thinking of using powers of ten of Planck units, but I wouldn't be so happy about the idea of decreasing the granularity of the second.

but prehaps we should be using base pi or base e instead
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Torn Apart By Dingos
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bonder wrote:I'd take a tip from the high energy physicists: redefine so that c = h = h_bar = mu_naught = epsilon_naught = pi = G =1.

High energy physicists actually do things like this (I admit I carried it a bit to the extreme) but then at the end of their calculations, they use dimensional analysis to find out how many c's and h_bar's etc. that they need for the correct answer.

Once, a high energy physics professor was doing a calculation in class and in order to get the right answer in the end said "and we can see through dimensional analysis, we need a 2*pi in here"....

How can pi be changed? I suppose a special angle unit which is not equal to 1 could be introduced, but pi appears in things that doesn't have anything to do with angles.

hyperion
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Well pi (and phi and other cool numbers) are just ratios. You can't change them.
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But I digress.

Vaelin
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### Re: Redefine the metric system

zenten wrote:Lets suppose you were given the power to redefine the metric system to make the values fit better. What would you change? Assume everything is called the same, and you still have the same prefixes with the same meaning, you just change the actual value for metres, seconds, grams, etc.

Personally? A meter would be the length of my foot. I could make and sell my own rulers and measure things easily.

Makes as much sense as the real meter: http://www.surveyhistory.org/the_standard_meter1.htm
If it's related to some ratio that requires 10 numbers to express... it's just as silly as any other length. The metric system is nice because you don't really have to do any math or make approximations to convert units in your head.
(They might as well just get as convoluted as they can... the meter is... the distance light travels in 1/(pi*1e8) seconds in a vacuum... or in e^(-20) {<- my favorite!} seconds... or 1/(2*sqrt(2)*1e8) seconds)

We will use units that we can easily wield. That's why there are certain metric units that even the scientific community fails to widely accept... the poor pascal... at least we can sort of talk about MPa (at least in atmospheric sciences).
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HYPERiON wrote:Well pi (and phi and other cool numbers) are just ratios. You can't change them.

Or can ye? I propose the tri-right angled-triangle as the basis for all measurements.

The length of the sides necessary to accomodate three right angles per triangle shall henceforth be defined as one metre, and can easily be determined through basic trig.
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SpitValve
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We should define everything in terms of cubits, including the fact that a cubit is different for each person.

gmalivuk
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LE4dGOLEM wrote:
HYPERiON wrote:Well pi (and phi and other cool numbers) are just ratios. You can't change them.

Or can ye? I propose the tri-right angled-triangle as the basis for all measurements.

The length of the sides necessary to accomodate three right angles per triangle shall henceforth be defined as one metre, and can easily be determined through basic trig.

Well, that's kind of how it started, on Earth anyway. See, the meter was originally 1 ten-millionth of the distance from the equator to the north pole, on a great circle route through Paris. I believe this distance (10,000,000 meters) is therefore the length of a side necessary to make a 270Âº equilateral triangle on the surface of our homeworld.

I think the earlier pi question arose because the only way h can have the same value as h_bar is if 2pi is 1.
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Luppoewagan
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I say we bring back cubits, talents, and handspans.

GMontag
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HYPERiON wrote:Well pi (and phi and other cool numbers) are just ratios. You can't change them.

Tell that to Carl Sagan.

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bonder wrote:I'd take a tip from the high energy physicists: redefine so that c = h = h_bar = mu_naught = epsilon_naught = pi = G =1.

High energy physicists actually do things like this (I admit I carried it a bit to the extreme) but then at the end of their calculations, they use dimensional analysis to find out how many c's and h_bar's etc. that they need for the correct answer.

Once, a high energy physics professor was doing a calculation in class and in order to get the right answer in the end said "and we can see through dimensional analysis, we need a 2*pi in here"....

Let me interpolate here: "dimensional analysis" = "looking at the answer in the back of the textbook and multiplying your answer to suit"?

HYPERiON wrote:Well pi (and phi and other cool numbers) are just ratios. You can't change them.
Not in Cartesian space; map a circle onto the right kind of cone, though, and pi can equal 1.

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toysbfun
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Let's make a second equal 10^10 oscillations of cesium-133. Or maybe some round number involving hydrogen. Planet's slowing down anyway, creating a discrepancy between Terran seconds and Metric seconds. Why bother pretending they're the same?

The metric system. How appropriate for my 100th post.

evilbeanfiend
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why bother pretending that's not how it's defined already?
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toysbfun
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Because then my watch would be ten percent slow? Or fast? Whichever.

evilbeanfiend
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you have a caesium-133 watch?
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gmalivuk
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evilbeanfiend wrote:why bother pretending that's not how it's defined already?

Because 9,192,631,770 is generally not considered to be a "round number".
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zenten
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gmalivuk wrote:
evilbeanfiend wrote:why bother pretending that's not how it's defined already?

Because 9,192,631,770 is generally not considered to be a "round number".

Anyone know of the smallest base where it would be?

toysbfun
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zenten wrote:
gmalivuk wrote:
evilbeanfiend wrote:why bother pretending that's not how it's defined already?

Because 9,192,631,770 is generally not considered to be a "round number".

Anyone know of the smallest base where it would be?

I don't think there is one. A script could probably confirm this by looking for an answer that's an integer to log x++ 9,192,631,770...or something along those lines.

RealGrouchy
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The problem with an hypothetical perfect metric system--particularly time--is that it assumes that the world can be conveniently decimated. However, there's no escaping the fact that the earth rotates 365 times as fast as it circumnavigates the sun.

Tie that into trying to find a decent base for measuring distance based on some nice clean fraction of the speed of light or something, and you get a bunch of (metaphorical) points that don't connect into a straight line.

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Mighty Jalapeno wrote:At least he has the decency to REMOVE THE GAP BETWEEN HIS QUOTES....
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mountaingoat
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RealGrouchy wrote:However, there's no escaping the fact that the earth rotates 365 times as fast as it circumnavigates the sun.
is this sarcasm?

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It seems like an evident and relevant truth to me. Year is a much more useful measurement than kiloday, and day is a much more useful measurement than centiyear. Time is more conveniently measured by something other than a metric system.
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bonder
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I propose a change slightly more radical than changing just the metric system. I think we should change from a base 10 number system to a base 12 number system and then modify the metric system to be based on powers of 12 rather than powers of 10.
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skeptical scientist
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Why would you want to do that when we have a base 10 number system?
Last edited by skeptical scientist on Tue Aug 07, 2007 7:04 am UTC, edited 1 time in total.
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SpitValve
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If we chose to all live in self-contained domes, we could ignore the year and go for kilodays instead. Hoorah!

bonder
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skeptical scientist wrote:Why would you want to do that when we have a base 10 number system?

Base 12, having more factors, would be a more convenient base than base 10. Just because we have 10 fingers does not mean that we need to have a base 10 number system: the Babylonians had a base 60 number system.

There are even groups advocating a change to a base 12 number system:
The merits of base twelve are due to the great factorability of the number twelve, the next really useful number being sixty, but this latter number is rather too large to be chosen as an every-day number base. Ten is unsatisfactory because its factors 2 and 5 include the prime 5 which in turn is not as useful as the prime 3 (though one professor of mathematics complained that I was not being really fair to the number 5 when I said this ... ). The dozen, and the dozen dozen, or gross, have shown their usefulness in packing and packaging over many, many years.

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zenten
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bonder wrote:I propose a change slightly more radical than changing just the metric system. I think we should change from a base 10 number system to a base 12 number system and then modify the metric system to be based on powers of 12 rather than powers of 10.

Oh, I agree too. I just didn't want to bring it up in the OP.

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SpitValve wrote:If we chose to all live in self-contained domes, we could ignore the year and go for kilodays instead. Hoorah!
Why stick to the old 24-hour days then? I think a ~30 hour day is more suitable for hunams. Why not make a day a nice, round 10^5 seconds (approx 27.8 hours)?