Units of Measurement

[Venusian Broon]

And yet the spacing of the Knots was common among all sailors and nobody thought to correlate that spacing to units of measure used on land.

I'd guess they used arc-minutes to divide it up and saw that it sort of came out at "roughly the same" as land miles, so left it at that!

Mind you the Scottish mile - at about 1.81km - was only about 40 metres or so away from the nautical mile.

 

[Alex The G and T]

A Knot is one nautical mile per hour. A nautical mile (1.15 statute mile) is equal to one minute of latitude.

 

[AllanR]

and there is the 10km ling Scandinavian mile. Scandinavian mile - Wikipedia

 

[Alex The G and T]

So, when The Proclaimers walked Five Hundred miles; we still don't have a clue how far away they actually got to.

 

[Ursa major]

nobody thought to correlate that spacing to units of measure used on land.

They got too caught up in trying to solve the problem of how to make the common/ship/chip log float on land.....

 

[Cthulhu.Science]

Turns out a Butt-Load is less than a Tun, but it is still quite a lot!

 

[Wayne Mack]

How about the astronomical unit (au), the distance from the Earth to the sun. "... since 2012 it has been defined as exactly 149,597,870,700 m."

Astronomical unit - Wikipedia

en.wikipedia.org

 

[Dave]

.. since 2012 it has been defined as exactly 149,597,870,700 m.

Yes, you'd think they might have rounded it up to 150,000,000,000 m given that the Earth's orbit is elliptical and varies up to 3% as Earth orbits the Sun (or in other words, 4,500,000,000 m).

 

[Cthulhu.Science]

Yes, you'd think they might have rounded it up to 150,000,000,000 m given that the Earth's orbit is elliptical and varies up to 3% as Earth orbits the Sun (or in other words, 4,500,000,000 m).

Yes, but there is an astronomer who pushed for 149,597,870,700 m because that distance occurs every year on August 22 -- That astronomer's birthday.

 

[Ursa major]

Surely that distance does not occur every year, given that we need leap years.

 

[Dave]

Twice a year, but maybe not exactly on that date, no!

 

[Foxbat]

So, when The Proclaimers walked Five Hundred miles; we still don't have a clue how far away they actually got to

If we assume (being Scottish) they were using the Scottish mile: 1.81 km = 1.124682 Smiles (Scottish miles)
Then 500 miles becomes 444.57010954234

Quite a mouthful for a song

Afterthought: maybe when recording it they meant to sing Smiles rather than Miles

 

[Cthulhu.Science]

Surely that distance does not occur every year, given that we need leap years.

Twice a year, but maybe not exactly on that date, no!

Sorry. My Cynical Sarcasm Font wasn't working.
But what other explanation could there be. When measuring distances in AU does anyone really care about a few thousand km one way or the other?

 

[Cthulhu.Science]

NASA, and the Jet Propulsion Laboratory (which manages the longest space flights) calculate Pi to 15 decimal places and that's it. They don't stop at 14. They do not continue on to 16. And 17 is right out.

From the explainer:
For JPL's highest accuracy calculations, which are for interplanetary navigation, we use 3.141592653589793.
1. The most distant spacecraft from Earth is Voyager 1. As of this writing, it’s about 14.7 billion miles (23.6 billion kilometers) away. Let’s be generous and call that 15 billion miles (24 billion kilometers) Now say we have a circle with a radius of exactly that size, 30 billion miles (48 billion kilometers) in diameter, and we want to calculate the circumference, which is pi times the radius times 2. Using pi rounded to the 15th decimal...that distance would be off by no more than the width of your little finger.

3. Let's go to the largest size there is: the known universe...It turns out that 37 decimal places (38 digits, including the number 3 to the left of the decimal point) would be quite sufficient...a single atom...

How Many Decimals of Pi Do We Really Need? - Edu News | NASA/JPL Edu

While world record holders may have memorized more than 70,000 digits of pi, a JPL engineer explains why you really only need a tiny fraction of that for most calculations â even at NASA.

www.jpl.nasa.gov

 

[Alex The G and T]

If we assume (being Scottish) they were using the Scottish mile: 1.81 km = 1.124682 Smiles (Scottish miles)
Then 500 miles becomes 444.57010954234

\

To recap what we have learned about miles:
A Nautical mile runs 1852 meters.
A Statute mile is 1609 meters long; being a resolved convention derived from the "English Mile" which varies around, roughly 2100 meters or somewhere between 79200 inches and 79320 inches according to how an inch is/was defined, heretofore, therein.

A Scandinavian mile runs between 11295 meters and 10688 meters; depending on who you ask, and when. The Scandinavian "Forest Mile" is only half a KM.

Thus, The Proclaimers are lost in a search area larger than the site of the wreckage of the Titanic Submarine. IF they had provided a compass heading, which they didn't; which makes their actual current location a total conundrum.

 

[Dave]

The Proclaimers are lost in a search area larger than the site of the wreckage of the Titanic Submarine. IF they had provided a compass heading, which they didn't; which makes their actual current location a total conundrum.

At least we do know that they began with sunshine on Leith. A missing persons search would use that as the place last seen, and start searching the places that they like. We also know they get regular letters from America. A great circle from Edinburgh Airport to John F Kennedy is 2829 nm, 5239 km with a heading of 282° (WNW).

 

[Pyan]

At least we do know that they began with sunshine on Leith. A missing persons search would use that as the place last seen, and start searching the places that they like. We also know they get regular letters from America. A great circle from Edinburgh Airport to John F Kennedy is 2829 nm, 5239 km with a heading of 282° (WNW).

I'd start by seeing if they were being joyful in Kilmarnock, as it's only 122,936, Megalithic Yards away.

 

[Ursa major]

When measuring distances in AU does anyone really care about a few thousand km one way or the other?

Some obsessive and/or anal people may very well care. A lot.

 

[Ursa major]

Let's go to the largest size there is: the known universe...It turns out that 37 decimal places (38 digits, including the number 3 to the left of the decimal point) would be quite sufficient...a single atom.

Then it seems to me that we should be using (at least) 37 decimal places, as that's "quite sufficient".

 

[Cthulhu.Science]

Some obsessive and/or anal people may very well care. A lot.

If you obsessively care about the specific number of km in a distance to something some number of AU away, maybe you should just use km.

For example. If I wanted to know precisely how many mm there are between my front door and the gate at the Tower of London I wouldn't use km to figure it out. The use of AU will always be an approximation anyway since it is only ever used with regards to two objects that are moving relative to each other. The distance between Earth and Pluto is constantly changing.

I'm sticking with the cynical Birthday conspiracy that I made up the other day.