4 ms·

'Three norths' alignment about to end

82 points by altilunium 10mo ago

oersted 10mo ago
> when the true, magnetic and grid norths met in the village of Langton Matravers in Dorset Love that, sounds like something Douglas Adams or Terry Pratchett would write :)
- rwmj 10mo ago
  Langton is obviously "long town", but Matravers is a very strange non-English sounding name, and indeed according to Wikipedia it's from French: https://en.wikipedia.org/wiki/Langton_Matravers#History https://en.wikipedia.org/wiki/Langton_Matravers#History
  - dspillett 10mo ago
    There are a lot of French influence in England's place names (and the language in general) from the couple of centuries after 1066 when the Normans ruled the roost.
    - jfengel 10mo ago
      The Normans still rule the roost. The dynasty name changes every so often but King Chuck 3 can trace his line straight back to William the Bastard.
      - School-Cotton 10mo ago
        Charles doesn’t “rule the roost” in any meaningful sense. Who knows whether Keir Starmer descends from Normans, but his predecessor certainly doesn’t.
        exe34 10mo ago
        Hey now, at least Rishi was elected to rule Britain - the old lady Vicky wasn't remotely connected to India but she was still Empress.
        jfengel 10mo ago
        I don't think India had a democracy before the Brits, either. Not that it gives anyone else the right to come in and declare themselves Raj. But Vicky wasn't the first to come to India and declare themselves in charge.
  - antonvs 10mo ago
    Town names in England are full of historical quirks that don’t sound like modern English - try browsing a map, it’s fun. Some of its place names are thousands of years old. Even names that seem very English now, like “York”, only seem that way because of their long historical presence. The town of that name started out around 70 CE as the Roman fortress Eboracum, which was a Latinized version of a Celtic name. Later, around 600 CE, the Anglo-Saxons reinterpreted the name as Eoforwic, because “eofor” meant “boar” in Old English, although the earlier name had nothing to do with boars, other than sounding similar. Then the Vikings came along in the 860s and called it Jórvík, an Old Norse adaptation of Eoforwic. Around 1000 CE, after the Norman conquest, the name was shortened to York. That has no meaning in English, other than the place name and its derivatives. Fundamentally, it’s no more or less English than Matravers.
    - louthy 10mo ago
      I've just bought a house in Alderwasley in Derbyshire, the nearest town is Wirksworth [1]. I assumed that, because this area was the heart of the industrial revolution [2], the town was an eponymously named workers town built for mill workers (there are actually entire towns in the area that were built for mill workers). Then I read the history on wikipedia: The name was recorded as Werchesworde in the Domesday Book of 1086 A.D. Outlying farms (berewicks) were Cromford, Middleton, Hopton, Wellesdene [sic], Carsington, Kirk Ireton and Callow. It gave its name to the earlier Wirksworth wapentake or hundred. The Survey of English Place-Names records Wyrcesuuyrthe in 835, Werchesworde in 1086, and Wirksworth(e) in 1536. The toponym might be "Weorc's enclosure", or "fortified enclosure". I just love how place names in the UK have evolved. [1] https://en.wikipedia.org/wiki/Wirksworth https://en.wikipedia.org/wiki/Wirksworth [2] https://en.wikipedia.org/wiki/Cromford_Mill https://en.wikipedia.org/wiki/Cromford_Mill
      - antonvs 10mo ago
        I agree, it's fascinating. I've lived in four countries, including England and the US, but I haven't seen anything quite like the UK names elsewhere. You do see a lot of indigenous names in the US, but they haven't evolved in the same way, probably largely because it's all so much more recent, but also because there was only one really one actual invasion, not waves of them coming from all different directions - Beakers, Celts, Roman, Norse, Anglo-Saxon, Norman. > I've just bought a house in Alderwasley in Derbyshire Congratulations! A quick check of the map shows you're right near Whatstandwell, Nether Heague, Shottle, Hognaston, and of course Knockerdown. It all makes Tolkien and Pratchett seem a bit unimaginative!
  - MangoToupe 10mo ago
    > Langton is obviously "long town" Are we speaking another language? C'mon, this isn't obvious at all. > but Matravers is a very strange non-English sounding name, and indeed according to Wikipedia it's from French Duh? Was "vers" not a major clue? ...what kind of language education did you receive? I was taught english, french, and latin. Were you taught german or dutch by any chance?
- dave1010uk 10mo ago
  Langton Matravers is about 2km north of the coast. The 3 norths will have met land at a place called Dancing Ledge, at about SZ 00000 76833 (50.59121, -2.00000). https://en.wikipedia.org/wiki/Dancing_Ledge https://en.wikipedia.org/wiki/Dancing_Ledge The quarry caves at Winspit are worth an explore if you're in the area - they've been used in the set for Dr Who, Blake's 7 and Andor. https://en.wikipedia.org/wiki/Winspit https://en.wikipedia.org/wiki/Winspit
skrebbel 10mo ago
How can "north" be a place? I feel like they forgot to add the content.
- x3n0ph3n3 10mo ago
  I think they are referring to a moving point on earth's surface where all 3 norths appear to be in the same direction. I agree it wasn't clear. What's also unclear to me is how all 3 could reliably be colinear, but maybe it's an aspect of spherical geometry that eludes me.
  - tor825gl 10mo ago
    The locus of points where magnetic north aligns with true north is a (one dimensional) curve. On one side of the curve magnetic north is too far to the east, on the other side too far to the west. Same for the locus of points where grid north matches true north. The two curves meet in some finite number of isolated points, at each of these all three directions are the same.
- oersted 10mo ago
  I agree, but the video at the bottom helped. You can draw a line between your location and the north pole, they talk about three variants: - Magnetic North: Shortest surface line to the magnetic north pole (simply in the direction of the compass at your location). - True North: Shortest surface line from where you are to the geographic north pole (based on the rotation axis?). - Grid North: A line to the same geographic north pole, but aligned to the longitude lines (EDIT: for a local UK grid standard, slightly different from the global one). I didn't fully understand the subtleties of why it's different from True North, something about the projection. Not sure if it's exactly to the same north pole, the rotation axis might also change slightly and I assume that the grid north point is fixed by convention? They are saying that there's a particular point where all three lines point in the same direction, and that point is moving.
  - chippiewill 10mo ago
    In the UK there's a standard grid used for local-only mapping: https://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid https://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid It's a transverse mercator projection rather than a mercator as you might often see because it minimises distortion over the UK as a whole which means that the distortion is as you move away from the meridian, rather than as you move away from the equator (with a regular mercator I think all points have the grid aligned with true North) This grid is setup such that it's origin is not on the prime meridian (at Greenwich), but 2deg west so only points on the line 2deg west are aligned with true north.
lrasinen 10mo ago
For most of Great Britain, the grid north differs from true north because the grid cells are fixed size, so they "fan out" compared to longitude lines. The exception is the 2°W meridian where the grid lines up. The magnetic north wanders around, and it now happens to match along the 2° meridian. But really the article is a year early, as the alignment point should make a brief landfall in Scotland late next year (which the article acknowledges later on). Or perhaps they expect Scotland to secede before that.
bjackman 10mo ago
The title is written specifically for UK readers, the actual subject is about the point of alignment leaving GB. (Also for anyone who was confused by this, it's not about the poles, it's about the point where the bearings for all three norths are equivalent. So a "compass" would point in the same direction regardless of what kind of north it reported. Took me a moment to understand!)
- louthy 10mo ago
  > The title is written specifically for UK readers Is it? The `.au` TLD might suggest otherwise.
  - MangoToupe 10mo ago
    True. There may be australians interested in other otherwise-obscure islands
  - deleted 10mo ago
    [deleted]
  - LeifCarrotson 10mo ago
    Not having thought about it too hard, if the three norths all align at -2 degrees west longitude, wouldn't they also be aligned at 178 degrees East longitude, somewhere near the east coast of New Zealand? Do the analogous "three souths" also have an alignment, and is it precisely opposite the north poles?
    - Majromax 10mo ago
      > Not having thought about it too hard, if the three norths all align at -2 degrees west longitude, wouldn't they also be aligned at 178 degrees East longitude, somewhere near the east coast of New Zealand? There is no required equivalent 'three souths' alignment because the Earth's magnetic field is not a pure dipole. Higher-moment variations can cause essentially arbitrary (but small) deviations of magnetic north/south from its dipole approximation.
- 10mo ago

82 points by altilunium 10mo ago

> when the true, magnetic and grid norths met in the village of Langton Matravers in Dorset Love that, sounds like something Douglas Adams or Terry Pratchett would write :)

rwmj 10mo ago
Langton is obviously "long town", but Matravers is a very strange non-English sounding name, and indeed according to Wikipedia it's from French: https://en.wikipedia.org/wiki/Langton_Matravers#History https://en.wikipedia.org/wiki/Langton_Matravers#History
- dspillett 10mo ago
  There are a lot of French influence in England's place names (and the language in general) from the couple of centuries after 1066 when the Normans ruled the roost.
  - jfengel 10mo ago
    The Normans still rule the roost. The dynasty name changes every so often but King Chuck 3 can trace his line straight back to William the Bastard.
    - School-Cotton 10mo ago
      Charles doesn’t “rule the roost” in any meaningful sense. Who knows whether Keir Starmer descends from Normans, but his predecessor certainly doesn’t.
      - exe34 10mo ago
        Hey now, at least Rishi was elected to rule Britain - the old lady Vicky wasn't remotely connected to India but she was still Empress.
        jfengel 10mo ago
        I don't think India had a democracy before the Brits, either. Not that it gives anyone else the right to come in and declare themselves Raj. But Vicky wasn't the first to come to India and declare themselves in charge.
- antonvs 10mo ago
  Town names in England are full of historical quirks that don’t sound like modern English - try browsing a map, it’s fun. Some of its place names are thousands of years old. Even names that seem very English now, like “York”, only seem that way because of their long historical presence. The town of that name started out around 70 CE as the Roman fortress Eboracum, which was a Latinized version of a Celtic name. Later, around 600 CE, the Anglo-Saxons reinterpreted the name as Eoforwic, because “eofor” meant “boar” in Old English, although the earlier name had nothing to do with boars, other than sounding similar. Then the Vikings came along in the 860s and called it Jórvík, an Old Norse adaptation of Eoforwic. Around 1000 CE, after the Norman conquest, the name was shortened to York. That has no meaning in English, other than the place name and its derivatives. Fundamentally, it’s no more or less English than Matravers.
  - louthy 10mo ago
    I've just bought a house in Alderwasley in Derbyshire, the nearest town is Wirksworth [1]. I assumed that, because this area was the heart of the industrial revolution [2], the town was an eponymously named workers town built for mill workers (there are actually entire towns in the area that were built for mill workers). Then I read the history on wikipedia: The name was recorded as Werchesworde in the Domesday Book of 1086 A.D. Outlying farms (berewicks) were Cromford, Middleton, Hopton, Wellesdene [sic], Carsington, Kirk Ireton and Callow. It gave its name to the earlier Wirksworth wapentake or hundred. The Survey of English Place-Names records Wyrcesuuyrthe in 835, Werchesworde in 1086, and Wirksworth(e) in 1536. The toponym might be "Weorc's enclosure", or "fortified enclosure". I just love how place names in the UK have evolved. [1] https://en.wikipedia.org/wiki/Wirksworth https://en.wikipedia.org/wiki/Wirksworth [2] https://en.wikipedia.org/wiki/Cromford_Mill https://en.wikipedia.org/wiki/Cromford_Mill
    - antonvs 10mo ago
      I agree, it's fascinating. I've lived in four countries, including England and the US, but I haven't seen anything quite like the UK names elsewhere. You do see a lot of indigenous names in the US, but they haven't evolved in the same way, probably largely because it's all so much more recent, but also because there was only one really one actual invasion, not waves of them coming from all different directions - Beakers, Celts, Roman, Norse, Anglo-Saxon, Norman. > I've just bought a house in Alderwasley in Derbyshire Congratulations! A quick check of the map shows you're right near Whatstandwell, Nether Heague, Shottle, Hognaston, and of course Knockerdown. It all makes Tolkien and Pratchett seem a bit unimaginative!
- MangoToupe 10mo ago
  > Langton is obviously "long town" Are we speaking another language? C'mon, this isn't obvious at all. > but Matravers is a very strange non-English sounding name, and indeed according to Wikipedia it's from French Duh? Was "vers" not a major clue? ...what kind of language education did you receive? I was taught english, french, and latin. Were you taught german or dutch by any chance?
dave1010uk 10mo ago
Langton Matravers is about 2km north of the coast. The 3 norths will have met land at a place called Dancing Ledge, at about SZ 00000 76833 (50.59121, -2.00000). https://en.wikipedia.org/wiki/Dancing_Ledge https://en.wikipedia.org/wiki/Dancing_Ledge The quarry caves at Winspit are worth an explore if you're in the area - they've been used in the set for Dr Who, Blake's 7 and Andor. https://en.wikipedia.org/wiki/Winspit https://en.wikipedia.org/wiki/Winspit

skrebbel 10mo ago

How can "north" be a place? I feel like they forgot to add the content.

x3n0ph3n3 10mo ago
I think they are referring to a moving point on earth's surface where all 3 norths appear to be in the same direction. I agree it wasn't clear. What's also unclear to me is how all 3 could reliably be colinear, but maybe it's an aspect of spherical geometry that eludes me.
- tor825gl 10mo ago
  The locus of points where magnetic north aligns with true north is a (one dimensional) curve. On one side of the curve magnetic north is too far to the east, on the other side too far to the west. Same for the locus of points where grid north matches true north. The two curves meet in some finite number of isolated points, at each of these all three directions are the same.
oersted 10mo ago
I agree, but the video at the bottom helped. You can draw a line between your location and the north pole, they talk about three variants: - Magnetic North: Shortest surface line to the magnetic north pole (simply in the direction of the compass at your location). - True North: Shortest surface line from where you are to the geographic north pole (based on the rotation axis?). - Grid North: A line to the same geographic north pole, but aligned to the longitude lines (EDIT: for a local UK grid standard, slightly different from the global one). I didn't fully understand the subtleties of why it's different from True North, something about the projection. Not sure if it's exactly to the same north pole, the rotation axis might also change slightly and I assume that the grid north point is fixed by convention? They are saying that there's a particular point where all three lines point in the same direction, and that point is moving.
- chippiewill 10mo ago
  In the UK there's a standard grid used for local-only mapping: https://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid https://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid It's a transverse mercator projection rather than a mercator as you might often see because it minimises distortion over the UK as a whole which means that the distortion is as you move away from the meridian, rather than as you move away from the equator (with a regular mercator I think all points have the grid aligned with true North) This grid is setup such that it's origin is not on the prime meridian (at Greenwich), but 2deg west so only points on the line 2deg west are aligned with true north.

lrasinen 10mo ago

For most of Great Britain, the grid north differs from true north because the grid cells are fixed size, so they "fan out" compared to longitude lines. The exception is the 2°W meridian where the grid lines up. The magnetic north wanders around, and it now happens to match along the 2° meridian. But really the article is a year early, as the alignment point should make a brief landfall in Scotland late next year (which the article acknowledges later on). Or perhaps they expect Scotland to secede before that.

bjackman 10mo ago

The title is written specifically for UK readers, the actual subject is about the point of alignment leaving GB. (Also for anyone who was confused by this, it's not about the poles, it's about the point where the bearings for all three norths are equivalent. So a "compass" would point in the same direction regardless of what kind of north it reported. Took me a moment to understand!)

louthy 10mo ago
> The title is written specifically for UK readers Is it? The `.au` TLD might suggest otherwise.
- MangoToupe 10mo ago
  True. There may be australians interested in other otherwise-obscure islands
- deleted 10mo ago
  [deleted]
- LeifCarrotson 10mo ago
  Not having thought about it too hard, if the three norths all align at -2 degrees west longitude, wouldn't they also be aligned at 178 degrees East longitude, somewhere near the east coast of New Zealand? Do the analogous "three souths" also have an alignment, and is it precisely opposite the north poles?
  - Majromax 10mo ago
    > Not having thought about it too hard, if the three norths all align at -2 degrees west longitude, wouldn't they also be aligned at 178 degrees East longitude, somewhere near the east coast of New Zealand? There is no required equivalent 'three souths' alignment because the Earth's magnetic field is not a pure dipole. Higher-moment variations can cause essentially arbitrary (but small) deviations of magnetic north/south from its dipole approximation.
10mo ago