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Re: Universal Constants

From: Steve Pugh <mafb90@d...>
Date: Thu, 12 Feb 1998 13:50:00 +0000
Subject: Re: Universal Constants

> Hypothesis: There is no universal measurement.
> Every measurement is relative, that is is defined in comparison to
> something else. 

True, very true but.....

> Examples:
>   Weight/Mass. This can be based on the atomic weight of a hydrogen
> molecule. But could be based on the mass of an electron or quark just
> well. And if measurements are based on this small of a unit, it makes
> VERY unwieldy to work with large masses such as that of an armored
> vehicle.

Yes, but you can simply define a larger unit of mass as 10^30 time that 
of the electron. Pointing at an electron is fairly easy. A simple 
(if large) number is a fairly easy concept to get across. 
Hence a scale of mass with a unit of ~1.0977 kg has just been designed.

>   Time: Time on earth is based on planetary rotation and orbit. If
> species developed on another planet the time would be different. Time
> based on change of energy states does not work because the time it
> is dependent on the amount of external energy. Time based on decay of
> particle will vary depending on what particle you choose.

Point at a pulsar that is clearly visible. Pulsars have a very well 
defined frequency. Time base now defined. Arbitrary but fine if both
parties can see the same portion of the universe.

>   Energy: Energy units are based on performing a specific task. That
> a calorie is an amount of energy it takes to raise the temperature a
> specific amount of water 1 degree at a specific altitude. As you can
> there are many factors involved.

Energy will always be a derived quantity. Energy is dimensionally 
mass x length squared over time squared. If you can define mass, length 
and time scales you have defined an energy scale.

>   Distance/Size: Distance is dependent on what you measure against.
> is why we developed standard measurements. But they are based on whim
> other factors such as time and heat.

The speed of light in a vacuum is a constant. We already have a timebase
from our pulsar so we can now define length. 

I have made one big assumption here. My assumption is that any 
alien race we communicate will not be living in very high gravity wells
or at speeds near to that of light. If they are then relativity comes
into play and their mass and time scales will be different but if we're
talking to them they probably understand relativity and so can make the
conversions just as easily as we can.


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