[HN Gopher] Go east from Seattle
___________________________________________________________________
Go east from Seattle
Author : simonebrunozzi
Score : 136 points
Date : 2024-06-03 16:31 UTC (6 hours ago)
(HTM) web link (finmoorhouse.com)
(TXT) w3m dump (finmoorhouse.com)
| oneepic wrote:
| I got really pissed when the headline didn't match the puzzle
| specs. Still kinda cool to think about at least.
| plorkyeran wrote:
| In this case it seems particularly egregious because the entire
| trick of the puzzle is that "face East and walk in a straight
| line" and "Go east from Seattle" _aren 't_ the same thing.
| shadowgovt wrote:
| Yes, and the difference is key: one attempts to travel the
| same distance with your left foot as with your right foot,
| and the other chases the direction the stars come up over the
| horizon.
| a_e_k wrote:
| > in a straight line along the Earth's surface.
|
| This already seems suspect, given that the earth's surface is
| curved. A true straight line from the starting point would take
| us off into space.
|
| So this feels like it's all just quibbling about different curved
| lines and which is closest to some definition of straight.
| runjake wrote:
| From the article: > To be pedantic, by
| 'straight line' here I really mean 'geodesic' -- the >
| generalisation of 'straight line' for curved surfaces and space
| as well > as 'flat', Euclidian spaces. > A
| geodesic is just the shortest path between two points in a
| surface. If > you're placed on a surface and continually
| walk "forward", by definition > you will trace out a
| geodesic. > Some people replying to my original
| tweet pointed out that a straight > line from the
| original point and direction would take you into space."
| 12_throw_away wrote:
| This is not correct, not even technically correct. Look up the
| term "geodesic".
| shadowgovt wrote:
| We need a word like "geodesic" precisely because "a straight
| line on a sphere" is an ambiguous concept.
| dylan604 wrote:
| Man, talking about missing the point even pedantically. Good
| job on impressing me with that
| elwell wrote:
| Is not pedantry the aim of this article?
| dylan604 wrote:
| At least the article gets it right though
| wang_li wrote:
| The article doesn't though. East is a path parallel to
| the equator on a spheroid. East of Seattle is a circle
| around the globe at a particular latitude. Facing the
| thing 1mm east of Seattle is a different heading than
| facing the thing 5000km east of Seattle.
|
| As has already been said as soon as you "go", if you
| aren't turning some infinitesimal amount you aren't going
| east. It's only a surprising result when misleading
| people by arguing that east is a particular heading.
| dylan604 wrote:
| But it just said in a straight line to the east. It gave
| you a cardinal direction to start. From there forward,
| you go in a straight line.
|
| It gets tricky if you suggest that you can only travel
| along a great circle in the direction of the rotation
| along that axis. Since the axis is actually tilted, this
| is the result you get from traveling along that great
| circle.
| cush wrote:
| The issue people have is with "straight". It's ambiguous.
| And the simplest, most intuitive interpretation of
| "straight" in the context of someone directing you to
| travel East, is to continue travelling East.
|
| It's like handing someone a compass pointing East, then
| saying "walk in a straight line", and expecting them to
| slowly travel in a wandering arc. It's insane.
| dylan604 wrote:
| Maybe so, but that's not how geometry works. If geometry
| worked by my interpretation, then I would have skated
| through that class with an even higher grade than I got
| by following the rules.
|
| Also, the GGGGP that I replied to started by trying to
| walking a tangential line to a sphere resulting in a
| space walk. That's like THC induced levels of strained
| thinking of the subject.
| wrs wrote:
| The puzzle doesn't say "go east". Only the headline does.
| cush wrote:
| Really? The title of the puzzle isn't part of the puzzle?
|
| Then the first line of the puzzle should be "completely
| ignore the title of this puzzle because it's somehow not
| part of the puzzle. It's unrelated. It will completely
| mislead you"...
| dylan604 wrote:
| If you have a problem with the title, then take it up
| with the submitter. The title of the TFA is "A path from
| Seattle". The article just says to walk in a straight
| line while facing due east. It does not say to travel
| East. I know I sometimes have an issue of reading over
| things too quickly to actually comprehend properly. Maybe
| this happened to you too?
| cush wrote:
| They changed the title after all the complaints. Also the
| HN title hasn't been updated yet.
|
| https://news.ycombinator.com/item?id=40567623
| dylan604 wrote:
| I guess that's the risk of being pedantic on the
| interweb. The thing being complained about can change,
| but those pedantic comments will be written in ink and
| look foolish in hindsight
| elwell wrote:
| > A true straight line from the starting point would take us
| off into space.
|
| How do you know? "Straight" relative to what? The expanding
| universe? Would continuous adjustments need to be made to
| account for the displacement due to that expansion? Does this
| then assume some 'outer' universe / reference container?
| wongarsu wrote:
| Obviously he meant a geodesic though spacetime, assuming
| constant speed. Of course your speed does become relevant,
| but as long as it's positive, "space" seems broadly correct.
|
| At least if we ignore the first 10km or so of your journey. A
| true straight line (geodesic) from the starting point would
| take us straight into a tree, hill or building. At that point
| the journey would end since humans can't phase through solid
| objects. You never reach another country.
| xixixao wrote:
| A true straight line from the starting point would take us into
| the Earth, because space is curved in its proximity.
| seadan83 wrote:
| Straight line of travel means you do not turn left or right.
| Different from heading continuously east. In the former,
| walking straight on the curved surface creates a curved path.
| In the latter, the compass needle will shift a bit as you
| travel, so you will be turning a bit to stay on the due
| easterly course.
|
| To your point, this a straight line relative to the traveller
| while staying on the surface of the globe (which is the
| premise).
| silisili wrote:
| I feel sorry for the first cop who gives you a field sobriety
| test.
| shagie wrote:
| Another neat aspect of a curved path but a straight line -
| Finding the longest straight line you could sail without hitting
| land
| https://www.technologyreview.com/2018/04/30/143150/computer-... (
| https://news.ycombinator.com/item?id=16965650 | 145 comments)
| madcaptenor wrote:
| Fb V xarj guvf jnf tbvat gb or n gevpx ohg V qvqa'g ernyvmr _ubj_
| pbhagrevaghvgvir vg jnf tbvat gb or - V gubhtug vg jbhyq raq hc
| znlor fbzrjurer nebhaq Frartny, qvqa 'g guvax vg jbhyq zvff
| Nsevpn pbzcyrgryl.
|
| (rot13-encoded, in case you want the fun of thinking about this
| yourself)
| _whiteCaps_ wrote:
| https://www.landfallnavigation.com/nga-nautical-chart-17-gre...
|
| For small scale marine charts, you can get ones that show the
| great circle effect.
| dmoy wrote:
| Semi related to this exercise, I really forgot how far north most
| of Northern Europe is. Not even talking Scandinavia... mentally
| in my head I didn't have France and Germany on the same-ish
| latitude as WA.
|
| All of England is north of the north-most point in the lower 48?
| Huh.
| wrenky wrote:
| Its the moderating effect of the Mediterranean! Its wild to see
| the temperature differences of Wisconsin, Montana, Dakota(s)
| compared to France & Spain. All that water helps insulate
| Europe even those its at a northern latitude.
| rileyphone wrote:
| There's also the oceanic currents carrying warm water from
| the gulf. Europe is in a very lucky position.
| PheonixPharts wrote:
| It's actually primarily from the AMOC which is bringing warm
| water up to the Northern Atlantic from the gulf [0].
|
| Fun fact: a possible consequence of climate change is the
| near term collapse of the AMOC which would cause drastic
| cooling in Europe (it also has more severe long-term
| consequences like leading to an anoxic ocean that emits
| hydrogen-sulfide instead of oxygen, such events have happened
| multiple times in Earth's past and played a part in major
| extinction events [1]).
|
| 0. https://en.wikipedia.org/wiki/Atlantic_meridional_overturn
| in...
|
| 1. https://en.wikipedia.org/wiki/Anoxic_event
| VinLucero wrote:
| Currently in Spain and originally from Seattle. Was thinking
| this very thing earlier today.
| kjsthree wrote:
| North of the _contiguous_ US but certainly not north of the
| _continental_ US.
|
| /pedantry
| dmoy wrote:
| Yea sorry, wrong word
| Foomf wrote:
| Over half of Canada's population lives farther south than
| Seattle, which is also crazy to think about.
| bumbledraven wrote:
| I had to check that for myself, and wow, you weren't kidding.
|
| 2015 population of Canada south of Seattle (~47.6degN): ~22
| million (https://imgur.com/a/azeTbwz)
|
| 2015 Canada population: ~35 million
|
| Sources:
|
| - NASA SEDAC Population Estimator
| (https://sedac.ciesin.columbia.edu/mapping/popest/gpw-v4/)
|
| - Statistics Canada (https://www150.statcan.gc.ca/n1/daily-
| quotidien/150929/dq150...)
| nemo44x wrote:
| It's great teeing off after dinner in Scotland.
| hedgehog wrote:
| Looking at a map Seattle is roughly the same latitude as Zurich
| and Budapest.
| delecti wrote:
| Lots of the comments are salty about the question's formulation,
| but it seems really straightforward to me within a couple
| sentences. I guessed Cuba, which was a too aggressive with the
| curve, but not too bad conceptually.
| madcaptenor wrote:
| I was not aggressive enough with the curve and thought it would
| hit the coast of west Africa somewhere around Senegal.
| frankus wrote:
| > So maybe half a point for "France" if that's what went through
| your head.
|
| I was thinking France, but I assumed the answer was non-obvious,
| so I guessed St. Pierre and Miquelon.
|
| But you'd have to start somewhere just south of Tacoma and just
| miss the tip of Nova Scotia on your way to the northern tip of
| Miquelon.
| GenerocUsername wrote:
| Tiniest clarification to the author, you should include the speed
| at which this person is travelling. Long duration of travel could
| result in techtonic shifts, so the traveller might even strike
| Seattle again. Maximum pedantry
| bastawhiz wrote:
| Depending on the speed of travel, countries and Seattle may not
| even exist. A cataclysmic event may occur and "east" may mean
| something very different (ask our friend Uranus).
| replygirl wrote:
| instructions unclear. the traveler drowned attempting to wade
| the atlantic, washed up on the virginia coast, and had willed
| for their family to scatter their ashes in italy.
| lalaithion wrote:
| In my opinion all maps of single airplane routes should be shown
| with a two-point equidistant projection. This clearly shows the
| straight line between the start and end as the shortest
| direction, and minimizes distortion along that line.
| Additionally, all points on the map have accurate distances from
| either point, and deviations from the geodesic (such as for
| administrative or weather related reasons) are easily seen.
|
| https://www.jasondavies.com/maps/two-point-equidistant/
| foota wrote:
| The most expensive trip you can take while staying within WA!
| Perth is in Western Australia, or WA.
| arh68 wrote:
| So it's hardly "go east". You're going momentarily east, then
| southeast.
|
| It is interesting what a "straight line" really means, though, in
| different contexts. I would have to say this is a poor puzzle,
| though, filed under cheap word tricks & ambiguities.
| re wrote:
| The mental bias towards the Cartesian 2d map projections being
| what we're so familiar with is strong, and I too instinctively
| think of "a straight line" as being a straight line on a map.
| But if you think of the problem at a different scale -- say
| you're standing 50 feet south of the north pole -- I feel like
| you would consider the definition of "face east, then walk
| forward in a _straight_ line " far less ambiguous.
|
| I'd also point out that it's a puzzle, not a standardized test
| question. Wordplay, tricks and ambiguities are par for the
| course.
| bialpio wrote:
| It's not a bias for 2d projection. If someone tells me to "go
| east in a straight line", I think about how practically I'd
| go about it. In this case, I'd take a compass, point myself
| to go east, and keep adjusting my bearing so that I keep
| facing east. Bonjour, France.
| happytoexplain wrote:
| Nobody familiar with navigation would say "go east in a
| straight line" because it's a paradox. That's why they say
| "maintain an easterly heading", or, for shorter distances
| (e.g. car directions), "head straight east", as in "exactly
| east", and _not_ "east in a perfectly straight line", which
| would be less relevant for shorter distances.
|
| It's also why the question is (paraphrased) "start facing
| east and go in a straight line", and not "go east in a
| straight line".
| davidw wrote:
| Of course it's not a perfectly straight line, because the
| earth is a curved object. Perfectly straight puts you in
| outer space.
| mynameisvlad wrote:
| The article quite clearly says "in a straight line _along
| the Earth's surface._ "
|
| Emphasis mine.
| happytoexplain wrote:
| Now that is, in fact, a silly gotcha. It's a third
| abstraction, irrelevant to the topic of two dimensional
| navigation. It is abstracted away for _both_ cartesian
| _and_ global concepts, and nobody is realistically
| confused by its absence.
| mc10 wrote:
| Perhaps the HN headline doesn't match the article, but the
| instructions say:
|
| > Imagine you begin a journey in Seattle WA, facing exactly
| due east. Then start traveling forward, in a straight line
| along the Earth's surface.
|
| where there isn't any wording saying "go east in a straight
| line".
| tacitusarc wrote:
| The most reasonable interpretation of this is to follow
| the latitudenal geodesic along its eastern path. You
| cannot claim that one geodesic is more "straight" than
| another in 3d Euclidean geometry, that is nonsense. But
| that is what the author does.
| pdonis wrote:
| _> the latitudenal geodesic_
|
| There is no such thing. A curve of constant latitude on
| Earth, except for the equator, is _not_ a geodesic.
|
| _> You cannot claim that one geodesic is more "straight"
| than another in 3d Euclidean geometry_
|
| In terms of 3D Euclidean geometry, neither a curve of
| constant latitude on Earth's surface _nor_ a great circle
| on Earth 's surface is a straight line/geodesic. Both are
| curved.
|
| If you restrict to the 2D surface of the Earth, a great
| circle _is_ a geodesic but a curve of constant latitude,
| except for the equator, is _not_.
| lxgr wrote:
| Except that the original instruction was "straight line",
| not "geodesic", so does it matter all that much which
| kind of non-straight-line one follows?
| lxgr wrote:
| Surely you mean Paris, Ontario, Canada? :)
| bsder wrote:
| Erm, is it bias if it's the standard for navigation?
|
| Historically, maintaining constant latitude (colloquial "Go
| East") was straightforward.
|
| By contrast, maintaining a Great Circle Route other than the
| equator was effectively _impossible_ until the 1800s. It
| requires the ability to track longitude which requires the
| invention of the marine chronometer.
| lxgr wrote:
| Did navigators before that actually follow rhumb lines? I'd
| have imagined they would at least approximate a great
| circle line somewhat by using a compass and dead reckoning,
| at least on very long crossings (where the difference
| between a rhumb line and a great circle line becomes
| significant).
| pdonis wrote:
| _> maintaining a Great Circle Route other than the equator
| was effectively impossible until the 1800s._
|
| It was at sea because the sea is constantly forcing your
| ship to change heading (wind, currents, etc.), and you have
| to compensate for that, and before the required navigation
| techniques were developed, there was no way to know what
| heading you _should_ be on at any given time to maintain a
| great circle route.
|
| But the article is asking you to imagine that you don't
| have to worry about that--which, if you're just walking
| across flat land, you don't. You can just "put one foot in
| front of the other", doing what comes naturally, and you
| will follow a great circle-- _not_ a curve of constant
| latitude.
| erikerikson wrote:
| A straight line along a constant latitude is a perfectly
| valid interpretation of the words. That interpretation was
| reinforced by the image. You're right that warning was given
| that it was a "puzzle". Still I'm with what it seems the GP
| was saying and felt the statements of correctness with
| certainty were intellectually dishonest. Rather than enjoying
| a clever thoughtfulness, perspective, and new knowledge, I
| appreciated the description of how they got that answer while
| feeling a bit abused. If the good and invalid interpretations
| had been recognized and the bad dismissed then the chosen
| "selected" I may have had smaller objections but recognized
| the right to choose, especially if there was something in the
| statement of the puzzle teasing that interpretation. In lieu
| of that it is an unsatisfying a game of guess the teacher's
| answer for me.
| PhasmaFelis wrote:
| > A straight line along a constant latitude is a perfectly
| valid interpretation of the words.
|
| It's a perfectly _understandable_ interpretation, and I
| wouldn 't belittle anyone who read it that way, but it
| can't be correct. A line of constant latitude cannot be
| straight unless it's on the equator. (Of course
| _technically_ no line that remains on the Earth 's surface
| is truly straight, but the puzzle's definition of
| "straight" meaning "turning neither left nor right" does
| seem like the best interpretation overall.)
| erikerikson wrote:
| > it can't be correct
|
| You are making a good point and I feel like I understand
| the basis of the original article's definition of
| straight as well as its basis for that definition.
| However, it does not seem to fully define the frame. If
| it had disambiguated the underlying terminology and
| assumptions, I'd maybe think some of the definitions
| unintuitive but ceded their right to define.
|
| The way I would regard my interpretation to be valid is
| to take the sphere and slice it at the current line of
| latitude. That seems like a historic if not reasonable
| interpretation of "exactly due East". Then for further
| visualization, consider a cylinder that is perpendicular
| to and centered on the edge of the flat surface. If you
| cut the cylinder at the starting point and unrolled it,
| the resulting path to the other end would be a 2D ray.
| Traveling the center of that cylinder along the ray seems
| like a way to go "exactly due East". As a bonus, the
| tradition of following a compass would take you on the
| same path. Given the ambiguity and what I think are
| reasonable interpretations of some of the terms, I
| believe that this is a reasonably reachable result that
| can be called valid and/or correct.
|
| The challenge here is the underdefinition of and
| opportunity to attach different semantics to the words in
| use.
| pdonis wrote:
| _> The way I would regard my interpretation to be valid_
|
| Involves getting rid of the 2-sphere and substituting a
| cylinder. Which changes the geometry. Yes, a circle cut
| in the way you describe out of a _cylinder_ is a geodesic
| _on the cylinder_. But that doesn 't mean it's a geodesic
| _on a 2-sphere_. It 's not.
|
| _> That seems like a historic if not reasonable
| interpretation of "exactly due East"._
|
| It's a reasonable interpretation of "exactly due East",
| yes, but it's _not_ a reasonable interpretation of the
| directions the article actually gave, which are:
|
| "Imagine you begin a journey in Seattle WA, facing
| exactly due east. Then start traveling forward, in a
| straight line along the Earth's surface."
|
| So you _start_ facing "exactly due East", but then you
| travel "in a straight line along the Earth's surface".
| The most natural interpretation of "in a straight line"
| is "without doing anything to change direction", i.e.,
| just "put one foot in front of the other" continuously.
| And if you do that, you will follow a _great circle_ ,
| _not_ a curve of constant latitude. To follow a curve of
| constant latitude, you would need to be making a
| conscious effort to _turn left_ as you went. That 's not
| traveling in a straight line.
| tacitusarc wrote:
| This is not how three dimensional Euclidean geometry
| works!
|
| Please see https://en.m.wikipedia.org/wiki/Geodesic
|
| Geodesics are "straight" along a curved surface,
| regardless of if they follow the circumference.
| pdonis wrote:
| The GP is correct. Only great circles on a 2-sphere are
| geodesics. Curves of constant latitude, except for the
| equator, are not.
|
| I'm not sure why you referenced the Wikipedia article you
| did, since it supports what the GP says and contradicts
| what you say.
| lxgr wrote:
| In Euclidean geometry, one generally does not return to
| the point of departure in finite time when following a
| straight line!
|
| So is a geodesic a straight line?
| lxgr wrote:
| No interpretation can be correct, since there are no
| straight lines on the surface of the earth.
| wrs wrote:
| The headline is poorly worded. The actual puzzle is unambiguous
| (begin facing east, then travel forward in a straight line
| _along the surface_ ).
| lxgr wrote:
| But there are no straight lines on the surface of a sphere
| (or geodesic)!
| pdonis wrote:
| Yes, there are--great circles _are_ geodesics of the
| 2-sphere. They are not geodesics of the surrounding
| 3-dimensional Euclidean space in which our Earth is
| embedded, but that 's irrelevant since the problem is not
| asking us to travel off of the Earth's surface.
| NegativeLatency wrote:
| Yeah it feels like a logical/semantic confusion, where the
| author gets to "well actually" the reader.
|
| To me "go east" means something more like "travel with a
| velocity vector that is always aligned with east on a compass",
| not "travel with a velocity vector that is fixed with east from
| your initial position"
| 015a wrote:
| Yeah; the "trick" of the question is "a straight line along a
| curved surface is actually a curved line", but even this isn't
| taking into account the Y-axis curvature of the earth; and thus
| the assumed-to-be "straight" line you're walking isn't even
| straight on the globe, its more like an arc along the planet's
| surface.
|
| You can't walk in a universally straight line on the planet.
| You can only walk in a straight line relative to something. In
| their example, when they say "walk in a straight line" they
| really mean something more-like "walk in a radially straight
| line, relative to the center of the earth, assuming the earth
| is a perfect sphere, etc"
|
| My assumption when reading the text of the question, which I
| think is _most_ peoples ' very reasonable assumption, is that
| you are traveling straight relative to the eastward direction;
| meaning, you're re-adjusting to continue to travel east,
| because that is a reasonable extension of the pretense "you
| leave Seattle traveling east".
|
| Its a bad question that is purposefully bad to trick people.
| soared wrote:
| More wordplay than anything else. "Go east and then continue
| straight" is different than "Go east and continue going east".
| Results from each are more predictable than misunderstanding the
| prompt.
| re wrote:
| Even if the prompt had been "Imagine a traveling from Seattle
| along a Great Circle path that initially heads east" to take
| out the "trick" part of the puzzle, I think I probably would
| have had a hard time visualizing the path without a physical
| globe in front of me.
| a_e_k wrote:
| Yes, if it had just mentioned that it meant a great circle, I
| would have felt like it wasn't such a gotcha question.
| hnburnsy wrote:
| Nope to me going straight east means keeping the north pole on
| your left while travelling on the same latitude. Answer is
| Canada.
| sokoloff wrote:
| If you go south from downtown Detroit, what's the first (non-USA)
| country you enter?
| madcaptenor wrote:
| bonus question: this was unknown to the writer of what song?
| pchristensen wrote:
| "Don't Stop Believin'"
| sokoloff wrote:
| Hmm. There's a reference in Don't Stop Believin', but I don't
| think that's the song you're referring to.
| happytoexplain wrote:
| This inspired similarly annoyed responses last time it was posted
| too. It genuinely surprises me to see that on HN. The whole thing
| can be summarized as "You might think of 'start facing East and
| go in a straight line' as being the same as 'maintain an Eastern
| heading', but latitude lines are only straight in the Cartesian
| abstraction we're used to, and not in reality."
|
| I hadn't thought about it before. It's interesting. It's not some
| kind of cheap or stupid trick intended to embarrass you. The
| negativity is truly baffling.
| ajkjk wrote:
| Well they called it "Go east" so maybe it feels like a trick
| that they didn't go east? Instead they worded their actual
| question in a subtly different way and then said "gotcha". It's
| a cool observation and would have been cool without the
| pedantry, too.
| brokencode wrote:
| Did they change the title of the blog post? When I open it,
| it says "A path from Seattle". The "Go east" part is only in
| the Hacker News post.
| mc10 wrote:
| The Substack version says "Go east from Seattle":
| https://finmoorhouse.substack.com/p/go-east-from-seattle
| finm wrote:
| Yes, I changed the title to the linked page to 'A path
| from Seattle' from 'Go east from Seattle' because, from
| reading the comments here, I agree the original title was
| too misleading. Just updated the title of the Substack
| post also.
| plorkyeran wrote:
| It's a trick question regardless of if the intent was to
| educate the reader or to make them feel stupid. You have to
| spot that the question both isn't asking what the title
| suggests it's asking and that the image isn't actually showing
| the direction you'd go. People tend not to like trick
| questions.
| hervature wrote:
| I don't think it is negativity. Someone else already called it
| out, but if you were to face east and then travel in a straight
| line, you would leave Earth's orbit. Thus, the question
| inherently is taking Earth into consideration. Their definition
| of "most obvious" is strange because you would encode a globe
| using spherical coordinates. A "straight line" East in
| spherical coordinates could be argued to be keeping the polar
| angle constant and increasing the azimuthal angle which would
| land you in France. The crux of the disagreement is what "most
| obvious" means.
| brokencode wrote:
| Idk, I think it's pretty clear based on the description what
| they mean.
|
| For one, the problem description says the straight line is
| "along the Earth's surface" so I don't think you can
| reasonably think it might go into space.
|
| And to me it seems reasonable to say a straight line means
| not turning. I personally imagined getting in a plane and
| going straight forward, assuming there is no wind to blow me
| off course.
|
| That is just the common understanding of straight. If
| somebody asks you to walk in a straight line, do you ask them
| what coordinate system they're using? No, you walk forward
| without turning.
|
| I guess "most obvious" can always be up to interpretation,
| though.
| rprenger wrote:
| Yeah as soon as I saw the "answer" I was like "yeah sure blah
| blah blah, you can make a trick question, but what IS the
| country that you'll actually hit if you walk East from
| Seattle". I was guessing England, but the right answer is
| France.
| pdonis wrote:
| _> what IS the country that you 'll actually hit if you
| walk East from Seattle". I was guessing England, but the
| right answer is France._
|
| Actually it's Canada, if "walk East" means "walk eastward
| along a line of constant latitude".
| karaterobot wrote:
| HN is full of people who like to be the "well actually" guy,
| and they're all getting well actually'd by this article. Of
| course they're annoyed. It must be just awful.
| lxgr wrote:
| If you ask a question to which the answer is "no,
| _actually_... ", don't be upset when you get a lot of "well,
| _actually actually_ " retorts, especially on this site :)
|
| And don't bring a geodesic to a semantics fight!
| tacitusarc wrote:
| As they state at the bottom, they are referring specifically to
| geodesics when they mean straight line. They then rule out the
| due east geodesic, despite stating you must travel due east.
| They claim this is because to do so would make the line no
| longer straight, but this claim is utterly nonsensical in the
| context of three dimensional geometries.
|
| This is a puzzle born of a misunderstanding of three
| dimensional Euclidean geometry.
| lxgr wrote:
| > start facing East and go in a straight line
|
| This is where the trick is hidden: To do this, you'd generally
| require a spaceship (or a _very_ impressive ladder) :)
| bagels wrote:
| The title is asking for something different from the problem
| statement.
| msikora wrote:
| In a truly "straight" line you'd go into space soon...
| adamredwoods wrote:
| Correct answer.
|
| BTW, this is all about which coordinate system for a "straight
| line", is being used.
| furyofantares wrote:
| I knew what this was gonna be and enjoyed the puzzle within those
| constraints. My first thought was Australia but then I decided on
| "somewhere in Africa, probably South Africa" which it looks like
| was a close guess.
| francisofascii wrote:
| Wonder how much question's success rate would increase if the
| question was, "what is the first continent you hit?"
| finm wrote:
| Author here.
|
| Reading these comments I agree that the title is far too
| misleading (and unnecessarily so). Changed to "A path from
| Seattle".
| cush wrote:
| Travel exactly due East. Now, ignore what East means. Then,
| ignore the giant white arrow pointing East into Montana in the
| image we've created to illustrate this question. Also, don't
| worry about anything called a Great Circle, it's completely
| unimportant. What country would you first encounter?
|
| Did you get it, idiot? No? Let me explain to you why you're
| wrong.
|
| First, you completely missed that the Great Circle I told you not
| to worry about doesn't actually follow along the white arrow I
| used to illustrate the problem. Clearly, if you completely ignore
| all the information that was given to you, and what East is, the
| answer is obviously Australia. Because if you were at the North
| Pole, a line going East would be a tight circle.
|
| Please like and subscribe. To leave a comment, first you must
| solve this simple math problem 6 / 2(1+2) = ?
| mc10 wrote:
| The instructions state the following:
|
| > Imagine you begin a journey in Seattle WA, facing exactly due
| east. Then start traveling forward, in a straight line along
| the Earth's surface.
|
| Where does it say to "travel exactly due East"?
| lxgr wrote:
| The instructions are impossible to follow, since there are no
| straight lines (in all three dimensions) along the Earth's
| surface.
|
| And if it's supposed to mean "a straight line when projected
| onto a map", I'd like to know: Which map projection? :)
| enoch_r wrote:
| [delayed]
| finm wrote:
| Author here -- I agree the image is misleading (and added a
| caveat to be clearer, though I could have made the arrow
| smaller).
|
| I don't think the question requires the reader to ignore what
| 'east' means, however. There is unambiguously one direction at
| Seattle (tangent to the Earth's surface) which is facing due
| east.
|
| I also didn't mean to take a patronising/arrogant tone to the
| reader and I'm sorry if that was the impression I gave.
| enoch_r wrote:
| FWIW I did not get that impression at all, and I'm bewildered
| by all of the combative comments here. It's a cool thought
| experiment!
| lIl-IIIl wrote:
| The way I'd explain it is:
|
| You have a perfect paper airplane. It flies in a straight line
| regardless of wind, rain, hail or snow. And it keeps in the air
| a really long time.
|
| You get into an air balloon over Seattle and launch your paper
| airplane directly East.
|
| The plane descends so slowly it can leave North America and go
| over the ocean and eventually will reach another country and
| still not touch the ground. What is the first country it will
| reach?
| chad_oliver wrote:
| No, it says face due east and travel in a straight line. Sure,
| the wording could have been clearer, but you're seeing
| misdirection that isn't there.
| enoch_r wrote:
| > Travel exactly due East. Now, ignore what East means.
|
| It's "face east, then travel in a straight line," not "travel
| due East" (though I agree that the title itself is misleading).
|
| IMO, it's a cool thought experiment because it demonstrates
| that an instruction to "travel in a straight line" is
| _incompatible_ with an instruction to "travel due East"
| (unless you're on the equator!) - as the North Pole example
| illustrates. Start 3 feet south of the North Pole and face
| east, then start traveling in a straight line. Obviously after
| 10 or 100 or 1000 miles of travel you'll be essentially due
| south of the pole - and in fact, if you take a single step to
| the left, you will be _exactly_ due south of the pole!
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