why are degrees of Lat/longitude split into minutes and seconds ?

maybe an obvious reason but i’m trying to refresh my almost non existent knowledge of the subject and although I’m aware that every 15 degrees of longitude there’s an hours time difference this doesn’t explain why 1 degree of lat or long is split into 60 minutes ( a measure of time )
if you can understand what i’m getting at and know the answer could you please serve me up a simple explanation as the old grey matter isn’t what it used to be .
thank in advance
Bill

Don’t try and match time difference and minutes of degrees. Think instead of minutes as 60ths of something (eg not necessarily an hour) and similar for seconds.

I don’t think there’s a reason as such, it’s a hangover from the Babylonians’ base-60 numbering system, just like the measurements of time.

One handy thing is that a ship travelling at one knot covers one minute of latitude per hour – but that’s not a reason for it as that’s just a definition of a knot.

noon is when the sun is highest in the sky wherever you are, indeed before the telegraph/rail we used “local time”.

so, longitude was measured by taking a local measurement of when noon was, and comparing it with a really accurate timepiece set using a standard reference for time (Greenwich meridian) – the difference between the two, being how far round the globe you’ve gone.

So, if you measure noon in Bristol, the sun reaches its highest point in the sky about 2 minutes after London

Yes, but that doesn’t explain why there are 360 degrees, each of 60 minutes, each of 60 seconds. If it was sensible, there would be 24 degrees not 360.

It has nothing to do with time or the earth, angles of any circle are just measured 360 degrees, each degree split in to 60 mins, each min 60 secs. As mentioned above is just a unit, would be same for a football.

15 Degrees = 1 hour because 360 / 24 = 15.

Although 1 minute of arc at the equator is approximately one nautical mile I expect it was the 1 minute of arc that came first.

Why do we have 24 hours though? Or seven days in a week. Who decided and made it universal?

Babylonians again, isn’t it? And probably universal because it was always easier to go with the existing system instead of inventing a new system when there was no real need.

There are 7 naked-eye-visible astronomical objects that move against the stars – the Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn. That could be an explanation.

Sounds reasonable, did n’t they try a 10 day week in Russia once to up productivity?

Wikipedia’d 360, allegedly it is based on the Greeks thinking there were 360 days in a year so seemed logical to divide a circle by that, hmmm.

I don’t think the Greeks were that daft – they would have had much better measurements – but it could be that it was a number reasonably close to 365-and-a-bit that could also be divided by lots of other numbers. It’s a good number for dividing up into subdivisions.

Lat and Long are divided the same as any other angles are. The base 60 is good for doing arthithmetic without using “decimals” [they are only called that in base 10, though]. You can divide 60 in half, thirds, quarters, fifths, etc. We use 10 for counting but stuck to 60 for time and angles, and until recently the UK used 12 for basic units of both distance and money. 12 has the same advantages as 60 except it doesn’t divide by 5.

What Greybeard said. And it means you don’t have to do any number fudging when doing calculations of longitude at latitudes other than the equator. A nautical mile is one minute of arc of latitude along any meridian, but at anything other than the equator it’s one minute of arc of longitude * cos(latitude). If that makes sense. Even reading it now it’s a crap explanation.

d until recently the UK used 12 for basic units of both distance and money.

But only for the the lowest value, it didn’t follow though

12 pennies in a shilling
20 shillings in a pound
21 shillings in a guinea

12 inches in a foot
3 feet in a yard
22 yards in a chain
10 chains in a furlong
8 furlongs in a mile

we still use furlongs and chains in horse racing and cricket
it all looks complicated but every 11 yr old would have been fluent in it – I was

thanks guys ..some great answers there and very helpful/interesting.
Bill

A lot of pre-metric systems come about from physically dividing and halfing things so a given object, measure or weight would be your starting point and you’d half it then half it and half it. With circles if you want to divide them up the simplest, most accurate way then you can divide it is into 6 using the same pair of compasses you drew it with, without adjusting them. So I’d imagine that the 360 degree thing came from divisions of division of devisions starting with those first 6.

Metric calculates more easily as numbers, but given simple tools physically dividing something up into 10 or 100 is quite difficult. Or if you do the halving thing in metric you get into awkward fractions very quickly ; 10 – 5 – 2.5 – 1.25 – 0.625 , it gets ugly very quickly

I was in the LBS talking about the pre-decimal money the other day (farthing, halfpenny, penny, threepence, sixpence, shilling, two shilling, half crown, crown and ten shilling note, it sounds complicated now but it was easy at the time)none of the staff had even been born pre-decimalisation. How old did that make me feel 😯

you have to be going back some if you remember using farthings and crowns

the crown was a serious size coin