Basis of the Meter

This is updated for last post.

Originally, in the 18th century, the meter was described as the length of a pendulum with the half-period of 1 second!  Which does base distance on time, but unfortunately also gravity.  Which slightly varies across earth causing this to be inaccurate.  This is when the French Academy of Sciences came in and took over the definition of a meter (damn metre).  They described it as one ten-millionth of the length of the equator to the north pole.  They used a longitute which passed through Paris.

There were many intermediary definitions of a meter between then and now (1983), see Wikipedia – Metre.  Long story short, the General Conference on Weights and Measures defines the meter (as of 1983) as “the distance travelled by light in a vacuum during a time interval of ¹⁄_299,792,458 of a second.”

The subsequent definitions of the meter after the French took it over was essentially aimed at refining the precision of the definition no matter where you may need to be calibrating.  I’m not clear on this, but it seems they made one refinement due to a miscalculation because of the assumption that the earth was flat.  This made the meter ¹⁄₅^th of a milimeter longer.

World Time Zones

Have you ever seen one of those world maps that shades out the region of the world experiencing night?  Well, I use an operating system called Ubuntu which allows you to set your computers location (and other locations you choose) and your system calendar displays the weather information and the map described above with pins in your location(s).

Here’s a interesting World Time Zone Map:

That made me realize that the latitudinal length of one’s country could be measured by time.  I wondered if there was any non-astronomical units of distance measured by time (such as arch-seconds).  Volume and Mass (~weight) measurements are based off of water (1mL = 1cc(cm³) == 1g | 1pint = 16fl. oz. == 1lb = 16oz).  “Distance” is defined by Metric Space.  Which seems like it can be independent of time and definitely independent of water measurements.  What if a long time ago people happened to base all the measurements on time?  Distance – time to travel, Volume – time to fill, Mass – time until balanced.  One ruler might ask another ruler, “How much time does your land consume?”

In case you’re wondering, cause I was, the distance from the oxygen atom to the hydrogen atom on a water molecule is 95.84pm, the distance between the two hydrogens is 117.42pm with a “bent” angle of 104.45^o.  (By the way the partial pressure of H₂O is 117 mm Hg oddly enough, I wonder if that is a coincidence).  If we stick with a gram of water, we have 3.3426×10²² molecules H₂O, which if spread out perfectly (measuring by distance between hydrogens) it would cover 3.9249×10⁹km (for your reference the circumference of the earth (equitorial) is 4.0075×10⁴km.  That means that a gram of water, if spread out completely, would go around the earth roughly 98,000 times!

Anyway, I wonder what the common distance measurements, well I guess I only care about the meter, are based off of.  All because of my computer’s system calendar…