300km is the wrong number. Metres are defined based on the speed of light, and it's 299,792,458 m/s (not pretty!). This is for historical compatibility reasons, and without any goal of nice factors. It takes exactly 1 ms for light to travel 299.792458 km. Physicists often use "natural" units [1] where the speed of light is 1.

[1] https://en.wikipedia.org/wiki/Natural_units

The speed of light in natural units is 1c.

Usually people omit c because it's power can be inferred.

And then they fail to mention to students that they're just omitting the c, causing a hilarious amount of confusion, half-truths and cargo-culting on the topic of natural units...

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Saying that the speed of light in natural units is 1 is like saying that one meter in SI units is 1.

(s, m, kg, 10) can be seen as basis vectors of a vector space. (Multiplication is "addition", power is "multiplication".) Another base of this vector space is (h, c, GeV, 10).

The speed of light has the dimension distance/time. Distance is a relative measure of space (length, height, depth), time is a measure of... time. When we talk about relativity, the distinction between space and time isn't very useful, so those are actually the same kind of measure. So distance/time is the same thing as distance/distance or time/time or 1.

I suspect this is precisely the half truths and cargo cutting you're referring to. Maybe you could explain what the problem here is.

True. We're talking about the prettiness and factors of the numerical values, and the terms in the original hyperfactorial don't have units at all.

*its

60 is the really important number. It does happen to have rather a lot of convenient factors. Cheers Babylon.

(I have checked the assertion and it is correct)

I believe they split up a circle into 360 degrees because it's close to the number of days in the year.

Finally less hate if barbarian. Sorry Babylonian.

10 hour 10 second easier.

A quarter pass 7.

(Actual 12 is a human number of look from earth. Both chi-na and ... is it a copy.)

It's always bugged me there's no "metric time".

1 metric minute = 100 seconds = 1.667 Babylonian minutes

1 metric hour = 100 metric minutes = 166.7 Babylonian minutes = 2.78 Babylonian hours.

1 day = 8.61 metric hours = 1436 Babylonian minutes = 23.93 Babylonian hours.

Thoughts?

I've always thought that if we are redefining time units a better solution might be 100000 metric seconds in a day (making them a bit shorter than the existing 86400 in a day) and otherwise the same relationships you've suggested:

1 metric minute = 100 metric seconds

1 metric hour = 100 metric minutes

1 day = 10 metric hours.

If rather switch to a base-12 number system

Slightly off topic, but my favorite units for c are feet per nanosecond. In those units c = 1 (plus or minus a couple of percent).

No mention of the foot per nanosecond is complete without this seminal scene between the great, late Grace Hopper and David Letterman: https://youtu.be/1-vcErOPofQ?t=4m43s

It's even closer if you use a 'metric foot' of exactly 30 cm. Then you're only off by 0.1%.

> metric foot

Why is that a thing?

Not sure, but most of those 'metricised' units are leftovers from Napoleon's push to make everything metric.

Maybe because 30cm is very close to 12 inches.

Which leads to my favorite way to think about it. One foot per clock tick of a 1Ghz processor.

Does this mean circuits in a 1 GHz processor can't be longer than 12 inches?

No information can travel more than a foot (11.8 inches) in a nanosecond. Grace Hopper used to give a talk where she held up a piece of wire that was that long to illustrate this limitation. [1]

The first Cray computers were designed in a cylindrical shape to keep the signal wires short. [2]

[1] https://www.youtube.com/watch?v=JEpsKnWZrJ8

[2] https://en.wikipedia.org/wiki/Cray-1

'twas an annular shape!

Ok..the backplane was annular

That's really interesting - only about 2% off.

Conversion Here: https://www.wolframalpha.com/input/?i=speed+of+light+in+feet...

Mine are gigahertz * inches. 11.8ghz * in is the speed of light. Gives you a feel for it and is practical. Want to find an antenna length? Ghz*inches are your friend.

That is great, never heard that one. Thanks

I always like the fact that there are π seconds in a nanocentury (within half a percent)

Speed of light is by choice too; the numerical value is in no way "fundamental"

Units of time are specifically chosen to have 5, 2, and 3 as factors.

Why not 4?

Because you want prime factors.

60 is indeed handy since it divides into 2, 3, 4, 5, and 6. 30 would be much less convenient. Better to drop the 5 (as evidenced by 12 and 24)

I think the gp just generalized a bit to much. Units of time weren't chosen for those (prime) factors. People had simply figured out long time ago that a dozen is a nice round number.

4=2^2?

I think that is fair as well. 60/4=15 but 30/4 is not a whole number.

No it isn't but a quarter of a half hour is still understandable and is seven and one half minutes which is 7' 30". The ancient Babylonian idea of using 60 (and 360 for angles) is absolute genius.

If you think about it, it is a bit weird but makes so much sense working in base 60. We all do it all of the time.

I believe 360 for angles came from 365 days in a year.