Mathematical clock

[dipsydoodle]

[ehrenfeucht games]

1. Whoever created it got 5:00 wrong. (nt)

[phantom power]

2. yeah, typesetting - factorial needs to be outside the radical

[BlueStreak]

3. Yeah, I was just looking at that.

9! is 362880

[pokerfan]

4. The French wanted to decimalize time

French Revolutionary Time: 10 hours in a day, 100 minutes in an hour, 100 seconds in an hour... If you're going to go metric, go all in.

http://io9.com/5886129/the-short-strange-history-of-decimal-time

The downside is that ten isn't evenly divisible into thirds or quarters. But we have ten fingers, so there's that....

[BlueStreak]

5. Why not 10 months too?

Days and years relate directly to the movement of the earth in relation to the sun, but months are a bit more arbitrary. I think it makes a lot more sense for the year to begin either on a solstice or equinox.

[pokerfan]

7. Time to face it, ten sucks as a base

The number twelve, a highly composite number, is the smallest number with four non-trivial factors (2, 3, 4, 6), and the smallest to include as factors all four numbers (1 to 4) within the subitizing range. As a result of this increased factorability of the radix and its divisibility by a wide range of the most elemental numbers (whereas ten has only two non-trivial factors: 2 and 5, with neither 3 nor 4), duodecimal representations fit more easily than decimal ones into many common patterns, as evidenced by the higher regularity observable in the duodecimal multiplication table.

http://en.wikipedia.org/wiki/Duodecimal

[BlueStreak]

8. In order for that to work, you would need to buy two of these

6 finger, 6 finger, man alive!

How'd I ever get along with five?

[pokerfan]

9. Or....

Count your phalanges! You can even use your thumb as a pointer.

[muriel_volestrangler]

11. Months aren't that arbitrary - they come from the lunar cycle

of 29.53059 days from new moon to new moon (or full moon to full moon). You round that up to 30, and you create a calendar of 12 30 day months. You've either already worked out that the year is about 365 days, or it will become apparent after a year or two of using a 360 day year that 365 is closer. So you say "OK, a division into 12 is convenient, and 30 is close; we'll make a few months 31 days". The need for leap years becomes apparent after a few decades. The only really silly bit of our calendar is February having 28 days, normally. You could have it as 5 or 6 months of 31 days, and the rest 30.

It seems the start of the year, relative to the winter solstice, was set by Julius Caesar and his Senate in a combination of astronomy, politics, superstition and when the new moon was the year he reformed the calendar: http://www.hermetic.ch/cal_stud/cal_art.html

To really confuse things, at some times in English history, the start of the year has been taken as 25th March.

From the 12th century to 1752, the civil or legal year in England began on 25 March (Lady Day)[7] so for example the execution of Charles I was recorded at the time in Parliament as happening on 30 January 1648 (Old Style).[8] In modern English-language texts this date is usually recorded as "30 January 1649" (New Style).

http://en.wikipedia.org/wiki/Old_Style_and_New_Style_dates

And then there's the move to the Gregorian calendar; which is responsible for the British financial year still starting not on 25th March, but April 6th; and for the October Revolution in Russia starting, as far as the West was concerned, on the 7th November ...

[Dr. Strange]

13. And don't get me started on gradients!

[NutmegYankee]

12. I just noticed that as well.

It needs to be sqrt(9)=3! or 6-1. Oh well.

[Blappy]

6. I bought a very similar clock

That is very similar to a clock from the triple nine society, sold at cafepress. One o'clock is slightly different, but the factorial is in the correct place at the 5 o'clock position.

[link:http://www.cafepress.com/triplenine.2445706|

[tridim]

10. It's that Herman Cain's clock?