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125 Years of Longitude 0 0' 00" At Greenwich
An anonymous reader writes "This week marks the 125th anniversary of the International Meridian Conference, which determined that the prime meridian (i.e., longitude 0 0' 00") would travel through Greenwich, UK. One of the reasons that Greenwich was agreed upon 'was that 72% of the world's shipping already depended on sea charts that used Greenwich as the Prime Meridian.' Sandford Fleming's proposal of a single 24-hour clock for the entire world, located at the center of the Earth and not linked to any surface meridian, was rejected / not voted on, as it was felt to be outside the purview of the conference."
And don't forget the 180th meridian that came with it. When you cross the 180th meridian, you have to set your watch back/forward 23 hours !
Quite a few people are unaware of it ;-))
http://adsabs.harvard.edu/full/1919PA.....27..416F
Everything I write is lies, read between the lines.
It's a wonderful thing to live a phlegms breath away from such a staple part of our species everyday lives.
I wonder how much longer it will take for the US to catch up?
For example, we continue to teach date formatted in a completely nonsense format (MM/DD/YYYY) instead of either high to low (YYYY/MM/DD) or low to high (DD/MM/YYYY) like the rest of the world. Plus using AM/PM instead of 24 hour ("Military Time") again like the rest of the civilised world.
Don't even get me started on our lack of metric....
Local time is one of those aspects of reality that could already be set to a more technologically requiring standard.
What would you set as a reasonable "perfect time" system?
I think it should be a combination of universal time and real (sun driven) time. So It could be 10:30 in universal time and 21:17 in sun time.
You'd go to work (for a local example) with solar time and expect a global movie release or an international package transport in universal time.
However, that system is not very reasonable. :)
It is worth noting that in the coordinate system most used today (WGS84), this is no longer true.
See this explenation or check google maps.
That's a yankeeism that is not traditionally used even in other parts of the US, let alone the broader English-speaking world. The standard way to say it would be "the first of April" which maps quite naturally to 1/4.
just thick black clouds like nothing we've seen yet again.
we also note that despite a possibly less criminal gov't., almost everything we read has been reduced/transformed into some lie as a result of professional media manipulation. a lot slicker than the spew of the good ol' boys nukem network.
They're BOTH standard lengths.
A stride or a handspan is equally appreciable by anyone with legs or hands, but only if they are nonstandard.
The metric system's touted benefit of normal conversion is incorrect, by the way. You can have the same benefit with imperial by measuring in kilofeet. How many feet in a kilofeet? 1000. A megafeet? 1000000. How simple! Much better than that metric thing!
See how silly that argument is?
As to the "liters are so easy to work out", that too is bunk. Your water is 1.0064 kg per litre at STP. At 110C it's a thousandth of that. And how many people care about plain old water? They work with milk, beer, oil, treacle and so on. So you still need to remember weird conversions with metric.
And the only thing left is the "how many inches in a chain?" query.
It's only ever asked in maths class.
NOBODY CARES how many inches in a chain.
NOBODY measures the distance to London in miles, yards, feet and inches. Miles does just fine. How many miles in 1000 miles? So easy to convert!
But back on topic, why put the clock at the centre of the earth?
1) Who's going to put it there
2) Who is going to be able to check it
3) WHY???
The third one is real. Why? Is it because 99% of the rest of the world didn't get the meridian (for good reasons at the time: do you change 76%+A LOT of all maps or do you change the 24% that don't use Greenwich? No brainer).
What does it give us?
Nothing.
What does it solve?
Leap seconds.
The ONLY problem with that is that you need your time aware product to be updatable for leap seconds and that adds a few cents to your $100 GPS locator.
But missing out on leap seconds means the stars change location faster and we have to update all the astronomy books and astronomy software and astronomy hardware.
The costs are about equal.
It's the gadget manufacturers trying to offload a cost onto someone else.
Just recognise it for what it is.
why then is it 1st Apri?
How many other Greenwich's are there at 0 longitude?
Moderation Total: -1 Troll, +3 Goat
It's called Riyadh Solar Time - look it up. It last one year year before they realised how much of a pain in the arse it was. Also, Japan used to have per-city time zones in five-minute increments, and that was a real pain for doing business, or calculating journey travel/arrival times. Discrete time zones for relatively large areas are just more practical in general.
nuff said.
I have tried finding a reference to this and can't. What does it mean by being located at center of the Earth and not linked to any surface meridian? Time zones are linked to surface meridian's right? So how would a system work that was not linked to anyplace on the surface?
And as always, I think grandpa Simpson's classic comment really sums up the attitude behind why so many Americans are reluctant to switching; “My car gets forty rods to the hogshead, and that's the way I likes it!”
/Mikael
Homer himself would say: Greenwich... mmmm.. pizza!
Set your phasers on "funky"!
Many people forget to deal with, or at least poorly handle time zones in software. I think it would be much easier to just adapt to using a single time for the entire planet ... they're just numbers. Who cares if you need to wake up at 23:00?
One of my favourite Jeff Atwood quotes is "All you UKers who live in UTC+0 are a bunch of dirty, filthy, stinking time zone *cheaters*".
What people may not be aware of is that the GPS prime meridian, as defined by the WGS 94 Geoid, is 100 metres east of the original - see this BBC article http://news.bbc.co.uk/1/hi/magazine/8266883.stm
The reason is that this kept the 90 degree west meridian in the same place the the original. Guess where that is...
Tells you where the power and money was when the GPS system was set up.
[from the wikipedia ]
El Hierro
The island was known in European history as the prime meridian in common use outside of the future British Empire. Already in the 2nd century A.D., Ptolemy considered a definition of the zero meridian based on the western-most position of the known world, giving maps with only positive (eastern) longitudes. In the year 1634, France ruled by Louis XIII and Richelieu decided that Ferro's meridian should be used as the reference on maps, since this island was considered the most western position of the Old World. (Azores lie further west, but they weren't discovered by Europeans till early 15th century, and their identification as part of the Old World is uncertain.) It was thought to be exactly 20 degrees west of the Paris meridian, so indeed the exact position of Ferro was never considered. Old maps (outside of Anglo-America) often have a common grid with Paris degrees at the top and Ferro degrees offset by 20 at the bottom. Louis Feuillée also worked on this problem in 1724. ...the british, always stealing stuff
[end]
http://en.wikipedia.org/wiki/El_Hierro#The_.22Meridian_Island.22
Anybody wondering why it's doesn't run through Paris? Take a look here
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
A clock located at the center of the Earth !? Call me old fashioned (and it won't be the first time), but I will use my cuckoo clock, thank you.
It's what makes time travel POSSIBLE!
When I go, I'm flying Air Bizarre. It's a good airline. You buy a one way round trip ticket. You leave any Monday, and they bring you back the previous Friday... That way you still have the weekend.
You guys wanna get anal about this stuff? We should have 13 months of 28 days (364 days) and a tack-on day, since there's 13 lunar cycles a year. Instead, we had some nutcase priest named Greg or something that decided back in the Crusading days. We should have a clock that does not change. Instead, we have Ben Franklin's BS. Congress in 2007 spent $150M studying DST, and found it was actually a net loss in energy. We should not have time zones. We should have a set UTC, and businesses and people adjust to that clock. We should have a day system similar to Internet Time a la Swatch. It may not have gone anywhere, but it's actually as clear as can be. It would be a great system to adopt. And finally, the reason that the metric system never caught on in Imperial areas is because while it makes sense, people have a tendency to handle smaller numbers better. Feet are often used in everyday measurements because they have actual feet on their body. We don't have meters on our body. If we could come up with something in the Metric system, maybe call it a "Third", you could convert people. 30 centimeters is user-unfriendly. So is 450ml when you can have a pint, though that's less a problem. People don't have to be adjusted into these new distance schemes. Just make gas be sold by liter, and put all road signs with km (mi), and tell detroit that all cars have to be km friendly. It's really not hard; we just don't have the spine politically to move the needle on something that is truly important, but often overlooked at trivial.
Seriously, standards have often been used to lock out competition.
- Video. The PAL standard is better quality than NTSC (Never The Same Color), so why did the Americas adopt an inferior option?
That's sort of like asking why we adopted the clearly inferior analog STDV standard instead of digital HDTV. NTSC was standardized in 1953, PAL was not standardized until 1963. Naturally, PAL was the superior standard...it was based around technology that was ten years more advanced.
...a single 24-hour clock for the entire world, located at the center of the Earth Wouldn't that be a bit difficult to read, what with all the molten lava and such?
I've abandoned my search for truth; now I'm just looking for some useful delusions.
There was a Speed Racer episode which dealt with that. Spritel got to race because they crossed the line and he was now old enough by a few hours or something like that.
right handed versus left handed traffic. solution best decided by vanuatu:
http://upload.wikimedia.org/wikipedia/en/9/9b/Vanuatu_driving.png
rail gauge. there's european and chinese, standard, but russia uses a broad gauge, which is a serious problem for economic development:
http://www.chinapost.com.tw/business/2008/01/11/138592/Beijing-to.htm
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Using the same base across all measurements is really convenient - parent is correct about that.
But GP is also correct in that it is super convenient for your measurement base to have many factors. A unit comprising 10 smaller units can be smoothly divided in half, but not in thirds or fourths. For that purpose, 12 is a much more useful number than 10. You guys are debating the orthogonal advantages of two different systems: both are correct.
So the ideal would be a base 12 metric system, with all units scaling by twelves and grosses, ideally paired with a base-12 arithmetic system.
Sadly, that's a pipe dream. The cultural inertia of base 10 is so strong we don't even think about it --- it makes the "strong" US attachment to imperial units look weak.
I stole this sig from someone cleverer than me.
That's the case with a lot of the things discussed in the GP... they were developed one place, then independently developed somewhere else at a later time. But by then, there was already an installed base in the first place, and you couldn't switch to the newer standard, even if it was better, because it was too expensive to scrap your existing investment. Then there's the tendency to have vendor lockin for a lot of stuff. So those are some of the reasons for the great thing about standards (there are so many to choose from!).
I think Pi/3 is better.
1.047 ...
If you inscribe a hexagon inside a circle, it's the difference in ratio between the curved and straight-line distances between two adjacent points, and as "one-point-somethingsmall", it has a nice fundamental look to it.
Nice and easy to visualise. You know that the perimeter of a circle is six-point-something times the radius, because the inscribed hexagon has six sides.
And it gets rid of those one-third bits when you're dealing with spheres.
Far as I can tell, the reason for using the 3.14 ... number doesn't seem to do with logic or geoemtry, it seems to be a hangover of the tools that Greek stonemasons used to use when making pillars. It's the ratio between the caliper-width of a pillar, and the length of a piece of string wrapped around the pillar.
But geometrically, it's not sensible to be comparing the length of the flat base of a semicircle against the curved sections of //two// semicircles. It's not comparing like with like. You either compare radius with perimeter, as the earlier poster said (~6.28....), or you compare diameter with semiperimeter (~1.57 ... ), or you compare radius against arc (~1.047 ... )
Pi itself is a pretty stupid number. It's the mathematical equivalent of the human appendix, or the QUERTY keyboard. IMO it's one of the most damning indictments of human civilisation that we're still using it.
I feel ill whenever I hear SETI guys talking about broadcasting PI as a way of contacting alien civilisations. Yeah, right, broadcast to the whole universe how dumb we are, why don't you ... :-Z
If I was an alien, and I picked up a transmission of "pi", it'd tell me that the species was arrogant, technologically advanced but mentally a bit retarded, and unable to understand deep relationships or alternative perspectives. It'd tell me that the species considered themselves mathematicians, but had some fundamental inability to see their own mental shortcomings. It'd be a species that wouldn't deal well with cultural conflicts, becuase they'd be sure that their own way was right, and they'd not be able to see the possibility of other points of view.
It'd be a species that you wouldn't ever want to have to deal with. So you'd warn everyone to stay away, and you'd draw up a contingency plan for eliminating the nasty species should they ever start building interstellar spaceships.
So if there are intelligent lifeforms similar to us nearby, with decent technology, we might be looking at a global extinction event as first contact
Thanks for that, SETI
Eric Baird
PAL and NTSC were designed for countries in which the mains frequencies were different.
PAL is 25 frames per second because it was designed to be viewed in a country in which domestic electric lights flickered at 50Hz.
US TV standards were based on a refresh rate of 30 frames per second (later 29.97), because the official US mains frequency was 60Hz.
Both systems were designed to minimise aliasing effects between the refresh rate of the TV screen, and the flicker of local domestic electric lighting.
Eric Baird
Well, Yes. The US generously built the GPS system to map the entire world, so that it could be used to target US planes and missiles at any point on the globe. It would have been a bit silly if the system only enabled the US military to bomb sites within the US.
This would have somewhat limited the system's military usefulness (for the US, at least).
GPS was opened up for worldwide civilian use, for free, so that foreign aerospace companies wouldn't launch their own competing system that enemy countries could then use to target sites within the US, and US targets abroad, without the US government having an "off switch" or control over the spoiler systems. Companies within the US have legal restrictions that prevent them from certain sorts of satellite or mapping activities that relate to US territory. Making GPS free for civilian use was supposed to eliminate the business model of any competing civilian geolocation satellite systems, including those outside US legal jurisdiction, because it's difficult to come up with a business model that competes with "free".
The EU is now finally putting up the Galileo system regardless (rollout commencing 2010), but throughout the project planning stages, the US has let it be known that it regards Galileo as an "unfriendly" system, and it's been made known that if there was ever any serious chance of hostilities breaking out between the US and another country, that seemed likely to result in the US being attacked, one of the first things that would be likely to happen would be the US shooting down the Galileo system's satellites.
So I think it's fair to say that the US has been quite keen for there not to be any other competing GPS-type system.
GPS is great, wonderful, marvellous, incredible. But let's not pretend that it was originally part of a great humanitarian plan, or that something like Galileo wouldn't have been launched years earlier if it wasn't for political considerations, Europe not wanting to antagonise the US, and European private industry not being able to create a business model for launching commercial geolocation satellites while GPS use was being given away for free, specifically to undercut them. Europeans have benefitted from free access to GPS for years (yippee!), but the price has been the lack of a system more closely tailored to local needs. In the end, we've decided that we really have to pay to put up our own system anyway.
In an ideal world, there'd be a reciprocal arrangement whereby American citizens would also be able to make use of Galileo if they wanted to, but I suppose there's a chance that the US Government might not want Galileo access generally available within their borders, and might take steps to prevent that happening.
Eric Baird
To be fair to GPS's accuracy, it was never intended to be a system that would allow locals to dial up locations that corresponded to their local street maps, or to help them find their parking places or the local restaurant. It's numbers don't have to agree with the "proper" latitude and longitude numbers for a site that appear on official local maps.
Its system was designed to produce a persistent numerical overlay that linked the position of a receiver with coordinates specified on US military satellite imagery. It doesn't matter for GPS that it puts Greenwich Observatory's nominal position "out" by 100 metres, as long as the US satellite imagery also offsets the observatory's nominal position by the same amount, so that if the US ever needs to aim a cruise missile down Greenwich's main telescope, that missile's going to get to the right place.
In that hypothetical, the missile wouldn't care that the observatory's nominal position doesn't agree with it's official position on official UK Ordanance Survey maps. GPS is designed to work with US military maps, calibrated to a convenient reference point in US territory rather than to Greenwich, UK. The US military has to have their own independent mapping system, because they can't afford to be reliant on foreign countries doing the job properly for them, and being 100% truthful about where their military installations are.
If you want to turn the dodgy GPS figures into "proper" survey numbers (eg, for archaeological reference work), you either use a different system, or you survey the place yourself, or you use an overlay mesh that converts GPS locations into "proper" locations. Assuming that Galileo comes online as planned, and they haven't buggered it up, and it hasn't been sabotaged technically or politically, there'll soon be an alternative consumer system anyway. What's important is that we keep the GPS coordinate for locations separate from other numerical descriptions of those locations, and don't mix up the different coordinate systems. Which is easy enough to do, I guess we just stick a "GPS" prefix on the front of a GPS location, "Gal" (or similar) on the front of a Galileo location, "OS" on the front of a UK Ordanance Survey location, or come up with some other handy set of abbreviations. As long as we all know that there are differences, and don't mix up the different sets of numbers (like Wikipedia coordinates and GPS coordinates) we should be okay.
Eric Baird
For a while, the US was seriously considering using the Washington Meridian as its "zero" reference for all US mapping. Similarly, at one point they were considering having a brand new unit of length, defined as the length of a pendulum that swung in exactly one second when dangled at sea level at latitude 45 degrees (which would have been similar to, but not quite the same as, the metre).
In the end they set aside the idea of having their own independent system, and went with what was already popular.
The reason why Greenwich Time was so popular wasn't especially political, it was just that Greenwich as a long-standing, reliable, well-funded, high-profile observatory that was practically on the Thames, really near to where all the international shipping came in to park to use the docks. An agreed time-base was critical for navigation, and Greenwich tried to provide one. In the 1830's they also instituted the Greenwich Time Ball", which was a visual signal that passing shipping could use to calibrate their clocks. Some places used cannons, but the speed of sound meant that if you were a way away, your timing would be off. Greenwich's light-signal was better, provided that you had your telescope pointed in the right direction at the right time.
Because it was near the docks, ships didn't have to worry about passing at exactly the right time - chances are, they'd be holed up there anyway. So "Greenwich Time" was a free, easy international timebase for shipping that let captains calculate longitude, lots of ship's captains carried Greenwich Time around with them to the rest of the world, and it was a natural reference for mapping.
It also didn't hurt when England standardised on Greenwich time nationally, so that in theory, you could get Greenwich Time at any English port.
By contrast, Washington Time wouldn't tie into to the same existing nautical map-base, there probably wasn't a huge amount of international shipping parked within view of the Washignton Monument, and since the US had trouble even insisting that US maps were drawn up with reference to the Washington Meridian and Washington time, they probably did the right thing by dropping the idea, and using the existing standard. It's easy to carry Greenwich Time around the whole UK and coastal Europe by boat, with very sensitive mechanical clocks, it wouldn't have been so easy to take Washington time to both US coasts via shipping. Things got easier with the railroads and telegraphs, but for US shippng to be redrawing all the existing sea-maps specifically for a new reference system that they didn't really need ... it probably wasn't a brilliant idea.
Eric Baird
72% of the world's shipping already depended on sea charts
With this kind of usage share, one may reasonably expect Internet Explorer to also stick around for another century and a quarter.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
It's much more difficult to change existing infrastructures; when they exist for longer times than to create a new infrastructure.
Still, to create a full new network of 230V the costs would be enorm for supplier and users. All devices have to be adapted.
We had a few years ago the adaption of 220V to 230V because of our (over)usage of raw power and power drops. That even took it's toll for many...
It has happened before from POTS to fiber; so; maybe it should be tought about to create a new, secondary network; but; for which reason exactly?
A device at 230V which takes 10A will be 21A at 110V. Safety wise, 230V would be safer, because the load required would be less.
For me they are damn right, since they got their born right of taking their stand at it. This doesn't mean I approve all actions of the/a same government....
I don't even know we got a standard office here in Europe which brings the plentoria of filters back to managable states; next to that car parts which are so freaking expensive, for a rubber often got asked 20 euro, while I'm not that stupid to be able to accept the production proces of that rubber; really; costs 10 euro to produce, to even give them 50% profit.
--- I am known for the ones who want to find me on the net. Is that a privacy risk or a privilege? One might wonder..
The UK is supposed to be replacing all its "height and width" signs on UK bridges etc with metric distances, because of the number of foreign lorry drivers who don't know the exact height of their articulated lorry in feet and inches, and keep hitting things. In fact, low bridges in the UK keep getting hit by UK residents in large vehicles, because even =we= can't work out height conversions on the spot in imperial!
I have a happy memory of once seeing someone try to drive an empty double decker bus under a bridge that was about eight inches too low. The resulting explosion of glass was one of the prettiest things I've ever seen (sigh).
That bridge was always getting things stuck under it. Once I even saw an army tank transporter firmly wedged under it.
"Miles per gallon" still seems to be lingering in the UK, but IMO it'll have to go, if only for the fact that there's not a single international standard for how big a "gallon" is supposed to be. AFAIK, US land-miles are now supposed to be the same as UK land-miles (they used to be slightly different thanks to the "old" US inch being different to the "old" imperial inch), but US liquid gallons and UK liquid gallons are still significantly different - the US gallon is based on the old abandoned UK "wine gallon", of 128 fl oz, whereas the later "imperial" gallon used in the UK is based on the "ale gallon" of 160 fl.oz. The US and UK fluid ounces are also supposed to be slightly different. Pints, too. So presumably the same car can have different local MPG ratings in the US and UK. If someone published MPG ratings in the UK, they'll presumably be wrong for a reader in the US, and vice versa.
Eric Baird
Bigger pints! More beer! Yaaay!
I've never heard anyone complain about fizzy drinks or fruit juices being sold in the UK by the litre, or about cans of drink coming in 330ml cans. It's only when it comes to milk that people seem to get funny about it.
Some years back, UK supermarkets changed some of their packaging and started selling milk in litres and whole fractions of a litre, and I thought it was really neat. And then, once I'd gotten used to it, someone must have complained, and they went back to selling them in pint-equivalents. I was really pissed off about that.
Eric Baird
But if you're saying that the choice allowed manufacturers to use the mains frequency as a timebase, and omit a load of timing circuitry from their TV sets, then that sounds like a much more convincing reason.
PS, while you're here, since you seem to know a bit about this - is it true that the US and UK tv standards defined different colour responses for screens and cameras, and defined different phospor "recipes"? I once read in a really ancient computer graphics textbook that because the phosphors were different, computer graphics people were advised that their animations' colours might look wrong if they showed their pieces abroad. I never really knew whether to believe that one or not (although there was a time when US imports shown on UK tv always seemed to make all the people look orangey).
Eric Baird