# What happens to a compass at the North Pole? **URL:** \ **Category:** Factual Questions\ **Created:** [March 4, 2009, 2:06pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268 "2009-03-04T14:06:16Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![jakeofalltrades1964](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@jakeofalltrades1964](https://boards.straightdope.com/u/jakeofalltrades1964)\ **Post date:** [March 4, 2009, 2:06pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/1 "2009-03-04T14:06:16Z")
When people first reached the North Pole, before GPS, they had to use a compass. How did they know when they reached the North Pole? How did they know when they reached the true North Pole as opposed to the magentic North Pole? Did the compass needle spin around crazily, or just stay pointed North no matter what? -Jakeofalltrades1964 ---
**Author:** ![Mk\_VII](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@Mk\_VII](https://boards.straightdope.com/u/Mk_VII)\ **Post date:** [March 4, 2009, 2:12pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/2 "2009-03-04T14:12:12Z")
As I recall, from reading about Polar expeditions past, the needle moves very slowly, or tends to point down. Solar observations are necessary to determine one’s position. ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [March 4, 2009, 2:14pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/3 "2009-03-04T14:14:02Z")
> [@jakeofalltrades1964](#): > > When people first reached the North Pole, before GPS, they had to use a compass. No. People have long understood that compasses were worthless in the far North. > [@jakeofalltrades](#): > > How did they know when they reached the North Pole? When the elevation of the Sun in the sky didn’t change in the course of a day. > [@jakeofalltrades](#): > > Did the compass needle spin around crazily, or just stay pointed North no matter what? Compass needles follow the force lines of the Earth’s magnetic field. The force lines behave erratically as you near the magnetic poles, so a compass will point hither and yon without much pattern. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [March 4, 2009, 2:17pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/4 "2009-03-04T14:17:58Z")
At the North Pole, a compass will give the direction of Chicago. This is not a joke – at 90 degrees North, a compass will point in the direction of the North Magnetic Pole – which happens to be on the same meridian as Chicago. ---
**Author:** ![Baffle](https://avatars.discourse-cdn.com/v4/letter/b/dec6dc/32.png) [@Baffle](https://boards.straightdope.com/u/Baffle)\ **Post date:** [March 4, 2009, 5:27pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/5 "2009-03-04T17:27:40Z")
> [@Polycarp](#): > > At the North Pole, a compass will give the direction of Chicago. This is not a joke – at 90 degrees North, a compass will point in the direction of the North Magnetic Pole – which happens to be on the same meridian as Chicago. [Wikipedia](http://en.wikipedia.org/wiki/North_Magnetic_Pole) claims that (in 2005) it was closer to the latitude of Calgary and trending west. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [March 4, 2009, 5:33pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/6 "2009-03-04T17:33:33Z")
> [@Polycarp](#): > > At the North Pole, a compass will give the direction of Chicago. I blame **Ed Zotti**. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [March 4, 2009, 5:33pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/7 "2009-03-04T17:33:46Z")
> [@Freddy\_the\_Pig](#): > > When the elevation of the Sun in the sky didn’t change in the course of a day. Doesn’t this presuppose that they were visiting on an equinox? ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [March 4, 2009, 5:38pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/8 "2009-03-04T17:38:04Z")
> [@Baffle](#): > > [Wikipedia](http://en.wikipedia.org/wiki/North_Magnetic_Pole) claims that (in 2005) it was closer to the latitude of Calgary and trending west. Longitude? Latitude is how far north or south. Or have I got those mixed up? Maps I’ve seen put the north magnetic pole on Victoria Island in the Arctic Islands. There, a compass would point _down_, assuming it was pivoted appropriately. I seem to recall that this is known as ‘dip angle’. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [March 4, 2009, 5:41pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/9 "2009-03-04T17:41:01Z")
> [@KneadToKnow](#): > > Doesn’t this presuppose that they were visiting on an equinox? No. On an equinox the Sun will stay at the same altitude all day, but will be on the horizon. In mid-summer, it will stay on the horizon, but at a 23.5 degree altitude. In winter… well, winter at the north pole is kind of a drag. ---
**Author:** ![Arkcon](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Arkcon](https://boards.straightdope.com/u/Arkcon)\ **Post date:** [March 4, 2009, 5:42pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/10 "2009-03-04T17:42:37Z")
If you’re very curious, read the wikipedia articles on the various polar explorations. What they did was take solar and stellar elevations, and plot them as they traveled, and they also used dead reckoning (figuring how fast they traveled, on average, for how long, on average,) all to prove, they were reasonably close to, or had at least passed, the pole. Nobody went there, to stick a barbershop pole in the ice and state, “It’s spinning around _ **this** _ point.” At least at the start of exploration. ---
**Author:** ![Rufus\_Xavier](https://avatars.discourse-cdn.com/v4/letter/r/eada6e/32.png) [@Rufus\_Xavier](https://boards.straightdope.com/u/Rufus_Xavier)\ **Post date:** [March 4, 2009, 6:06pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/11 "2009-03-04T18:06:08Z")
> [@tdn](#): > > No. On an equinox the Sun will stay at the same altitude all day, but will be on the horizon. In mid-summer, it will stay on the horizon, but at a 23.5 degree altitude. In winter… well, winter at the north pole is kind of a drag. Not if you’re Santa Claus. 😉 ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [March 4, 2009, 6:15pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/12 "2009-03-04T18:15:10Z")
Establishing that you are actually at the North Pole is kind of tricky. Ask [Richard Byrd](http://en.wikipedia.org/wiki/Richard_E._Byrd#Claimed_North_Pole_flight.2C_1926). Note that they used sextant readings of the sun. It’s hard to do stellar readings unless you’re travelling in winter (which is of course not such a fun thing). ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [March 4, 2009, 7:21pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/13 "2009-03-04T19:21:19Z")
> [@tdn](#): > > it will stay on the horizon, but at a 23.5 degree altitude Okay, I got that my understanding was confused, and I get your explanation, but someone please tell me that this part is still confusing. 🙂 ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [March 4, 2009, 7:35pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/14 "2009-03-04T19:35:09Z")
> [@KneadToKnow](#): > > Okay, I got that my understanding was confused, and I get your explanation, but someone please tell me that this part is still confusing. 🙂 The typo probably didn’t help much. 😉 On any given day, the Sun will appear at some altitude off the horizon. How much depends on the time of year. It will appear to circle you once per day, but will stay at that same altitude. ---
**Author:** ![Walton\_Firm](https://avatars.discourse-cdn.com/v4/letter/w/45deac/32.png) [@Walton\_Firm](https://boards.straightdope.com/u/Walton_Firm)\ **Post date:** [March 4, 2009, 8:10pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/15 "2009-03-04T20:10:13Z")
> [@Sunspace](#): > > There, a compass would point _down_, assuming it was pivoted appropriately. I seem to recall that this is known as ‘dip angle’. That is something interesting I learned while preparing for my first trip to the southern hemisphere. Strictly speaking, a compass needle does not point north or south; it aligns itself with the field lines of the Earth’s local magnetic field, which do not necessarily point straight to either the true or the magnetic north pole. In the south of Africa, for example, the difference between true north/south and the local magnetic field lines can be as great as 30 degrees. This is called the magnetic declination. However, those magnetic field lines also have an angle towards the ground, which gets greater as you get closer to the poles. At the north or south pole, a free-floating magnetized needle would indeed stand straight up. This is called the inclination of the magnetic field. When using a typical flat hand compass, the inclination can cause the needle to scrape the bottom of the compass housing, preventing it from rotating freely. Compass manufacturers know this, so they balance the needle so that it will work right in the latitudinal area where they expect it to be used. If you purchase a compass in Northern Europe and then use it while traveling through Southern Africa, you’ll have problems. More high-end compasses solve this problem by having a little bar magnet in the pivot axis, while the ‘needle’ itself is not magnetized and can dip up and down freely. ---
**Author:** ![Baffle](https://avatars.discourse-cdn.com/v4/letter/b/dec6dc/32.png) [@Baffle](https://boards.straightdope.com/u/Baffle)\ **Post date:** [March 4, 2009, 9:44pm UTC](https://boards.straightdope.com/t/what-happens-to-a-compass-at-the-north-pole/488268/16 "2009-03-04T21:44:57Z")
> [@Sunspace](#): > > Longitude? Latitude is how far north or south. Or have I got those mixed up? Whoops. You’re right; my mistake.