# Incorrect Data On Webpage

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This song ...

http://www.acme.com/jef/singing_science/long_lat-32.MP3

Pointed to by this webpage

is WRONG (in general usage anyway)

They say that LONGATUDE is the number of degrees from Greenwich England

Isn’t longitude the time from Greenwich (or to depending on E or W)?

Well I assume on some system you could use degrees but that's not the "norm".

BTY 1hr=15deg so I guess it's OK but confusing to the tadpole.

Line of longitude measure the distance from the Prime Meridian.

You are right that the prime meridian does have something to do with time, but it also is the arbitrary starting point to measure distance around the globe. The equator is an obvious zero point between the top of the earth and the bottom of the globe, but people had to pick a "middle" for around the globe--and the spot they picked was Greenwich, England. An imaginary line runs from the north pole to the south pole through Greenwich, and that line is the Prime Meridian.

http://www-istp.gsfc.nasa.gov/stargaze/Slatlong.htm

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

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

http://wwp.greenwichmeantime.com/

The problem of longitude is linked with timekeeping in an intimate way.

360 / 24 hours => each degree of longitude is equivalent to 4 minutes of time (for the sun to travel one degree of arc)

For instance, when you are standing at 90 degrees west, this implies that the sun will take 6 hours to get from the prime meridian to you, which is why the central time zone is GMT -6 hours.

For sailors, the problem of logitude was a matter of having an accurate clock so they knew what time it was at home. Then when the sun was directly overhead, they could determine their longitude by knowing the time on the clock they took from home (no relativistic effects, of course!).

(There is a great book about it: http://www.amazon.com/gp/product/0140258795/)

My question is, who is the Greenwich, and why do we allow her to keep the world's time?

After a bit of research, I found out the following:

The Greenwich is the consort of the Green Man, a nature spirit from the Celtic mythology of the British isles. So the story goes, way back in the mists of history, the Time Being decided to delegate some of his authority by appointing one of the many wiches who existed back then, as guardian for the world's time. The choice eventually came down to three wiches: The Sandwich, the Norwich, and the Greenwich. Each of them was asked to demonstrate her qualifications for the job.

The Sandwich worked day and night for a month, and fused sand into an hourglass the likes of which the world had never seen, one hundred miles high and fifty broad, which would keep time precisely, down to the smallest part of a second.

The Norwich was determined to do even better. She set all the stars in their courses to revolving around her favorite (the North Star), in perfect lock-step synchronization, forming a precision clock the size of the entire cosmos. The stars continue in these circular paths to this day.

The Greenwich, seeing what the other two had done, calmly raised her hand and called upon the forces of nature, and the Sandwich and the Norwich were immediately whisked away by an immense storm, never to be heard from again.

Thus, the Greenwich was appointed as the guardian of earthly time for the simple reason that she can be really mean when she doesn't get her way. Hence the term "Greenwich Mean Time".

Everything I ever needed to know I learned from the Geocaching forums

I like this description best:

The Greenwich Meridian was chosen to be the Prime Meridian of the World in 1884. Forty-one delegates from 25 nations met in Washington DC for the International Meridian Conference. By the end of the conference, Greenwich had won the prize of Longitude 0º by a vote of 22 in favour to 1 against (San Domingo), with two abstentions (France and Brazil). There were two main reasons for the victory:

1. the USA had already chosen Greenwich as the basis for its own national time-zone system.

2. at the time, 72% of the world's commerce depended on sea-charts which used Greenwich as the Prime Meridian.

The decision, essentially, was based on the argument that by naming Greenwich as Longitude 0º, it would inconvenience the least number of people. Therefore, the Prime Meridian at Greenwich became the centre of world time, and the starting point of each new day, year and millennium.

Borrowed from here.

I have also heard that the world's commerce depended on the sea-charts because the UK more or less dominated the seas.

Honestly I haven't listened to or critiqued the MP3 for some time, but I can see how it would be confusing. I don't own the original track so I could clarify it in the glossary. But is it a big issue that requires clarification? I probably just need a couple acknowledgements of this.

Honestly I haven't listened to or critiqued the MP3 for some time, but I can see how it would be confusing.

The OP was wrong. Longitude is, indeed, the number of degrees from the Prime Meridian. The song is correct.

The only issue might be the characterization of longitude as the "distance from Greenwich England," which I can see perhaps being slightly confusing. But not in the way the OP meant.

Edited by fizzymagic