thekafka Posted January 18, 2005 Share Posted January 18, 2005 reports have come out from nasa, reported by msnbc that due to the magnitude of the quake that caused the sunami, it knocked the earth off its axis, and doing so moved the north pole an inch. what does this mean for gps unit accuracy and coordinates? can this effect our recievers or geocaching from now on? Quote Link to comment
rebapac Posted January 18, 2005 Share Posted January 18, 2005 It depends on which way the earth moved. WAAS enabled GPSr's could be more accurate by an inch (tongue in cheek). Quote Link to comment
+The Waldo's Posted January 18, 2005 Share Posted January 18, 2005 Know wonder I haven't been able to find a dadgum thing lately Quote Link to comment
+flask Posted January 18, 2005 Share Posted January 18, 2005 the poles move regularly. any large geological event changes the earth's wobble slightly. you probably won't notice, unless you're one of the lucky few whose job it is to monitor the exact location and to move the ceremonial pole marker. Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 the poles move regularly. any large geological event changes the earth's wobble slightly. you probably won't notice, unless you're one of the lucky few whose job it is to monitor the exact location and to move the ceremonial pole marker. Good thing they have a GPS to tell them where the new spot is. Quote Link to comment
WH Posted January 18, 2005 Share Posted January 18, 2005 I'm not any kind of scientist, but since the GPS satellites are in orbit around the earth, wouldn't they move with it? Quote Link to comment
+Milbank Posted January 18, 2005 Share Posted January 18, 2005 I'm not any kind of scientist, but since the GPS satellites are in orbit around the earth, wouldn't they move with it? Good question. I find it interesting that they can tell the north pole moved a inch. Now if someone can tell us that all the gps Sats. moved a inch too...... Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 I'm not any kind of scientist, but since the GPS satellites are in orbit around the earth, wouldn't they move with it? They wouldn't move with it since they are not physically connected. Quote Link to comment
WH Posted January 18, 2005 Share Posted January 18, 2005 (edited) I'm not any kind of scientist, but since the GPS satellites are in orbit around the earth, wouldn't they move with it? They wouldn't move with it since they are not physically connected. They are held in place by the force of Earth's gravity, so it's reasonable to assume that if the earth moves, the satellites move with it. Thats the same reason the satellites, moon and all other space junk follow us around the sun each year. Edited January 18, 2005 by WH Quote Link to comment
+Jamie Z Posted January 18, 2005 Share Posted January 18, 2005 Whether or not the satellites moved really depends on what is meant by the question. The satellites orbit the earth's mass. If the earth's mass moves (such as in orbit) then the satellites follow. If the earths mass is simply repositioned (such as in an earthquake or its daily rotation) it would have no effect on the satellites. So in the case of an earthquake, which would have basically negligible effect on the earth's center of mass, the satellites never even notice. Jamie Quote Link to comment
Mushtang Posted January 18, 2005 Share Posted January 18, 2005 I posted a DNF yesterday. But after reading this thread I went back and looked an inch off from the coordinates, and I saw the ammo can! Sweet! One more find. Quote Link to comment
+El Diablo Posted January 18, 2005 Share Posted January 18, 2005 Of course your compass will be off an entire inch now. You might as well throw them away! El Diablo Quote Link to comment
+flask Posted January 18, 2005 Share Posted January 18, 2005 i think the magnetic poles are still where they used to be. Quote Link to comment
+The Jester Posted January 18, 2005 Share Posted January 18, 2005 Yes, but declination is off by an inch. So your map & compass will be off too! Quote Link to comment
+El Diablo Posted January 18, 2005 Share Posted January 18, 2005 Yes, but declination is off by an inch. So your map & compass will be off too! And if your off by an inch...how ya gonna find a micro? El Diablo Quote Link to comment
+flask Posted January 18, 2005 Share Posted January 18, 2005 same way i always do. Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 I'm not any kind of scientist, but since the GPS satellites are in orbit around the earth, wouldn't they move with it? They wouldn't move with it since they are not physically connected. They are held in place by the force of Earth's gravity, so it's reasonable to assume that if the earth moves, the satellites move with it.... You are right they orbit because of the gravity. The catch is you have to move the gravity. If you rotate the planet an inch, did you move the pull of gravity? Now if you moved the earth an inch over to the left... But that doesn't have to move the location of the north pole. The tweak in the earths wobble does move the mass/gravity well/whaever you want to call it so the chanbe wobble if pronounced enough might cause a slight tweak to the satalites orbit. Quote Link to comment
thekafka Posted January 18, 2005 Author Share Posted January 18, 2005 the question is, will this throw off our electronic compasses, and does it effect where our gpsr's will tell us the caches are? or is the inch so negligible that it wont have a real effect? Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 the question is, will this throw off our electronic compasses, and does it effect where our gpsr's will tell us the caches are? or is the inch so negligible that it wont have a real effect? Your compass electronic or not, points at magnetic north (more or less). If that moves an inch...you would be hard pressed to notice it. The magnetic north pole moves anyway. That movement changes the declination and you need to know the declinatoin to calibrate your compass to true north. The inch is negligable. Quote Link to comment
+Ambrosia Posted January 18, 2005 Share Posted January 18, 2005 I posted a DNF yesterday. But after reading this thread I went back and looked an inch off from the coordinates, and I saw the ammo can! Sweet! One more find. Quote Link to comment
+Klondike Mike Posted January 18, 2005 Share Posted January 18, 2005 only an inch?!? are you sure?? gee it was so cold here last week I could swear it was at my front door Quote Link to comment
+GixxerUT Posted January 18, 2005 Share Posted January 18, 2005 reports have come out from nasa, reported by msnbc that due to the magnitude of the quake that caused the sunami, it knocked the earth off its axis, and doing so moved the north pole an inch. what does this mean for gps unit accuracy and coordinates? can this effect our recievers or geocaching from now on? http://www.nasa.gov/home/hqnews/2005/jan/H...earthquake.html NASA scientists using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation. They also found the earthquake decreased the length of day by 2.68 microseconds. oh great.......now I have less time to geocache Quote Link to comment
+fly46 Posted January 18, 2005 Share Posted January 18, 2005 *slaps head* It moved an inch. ________ <-- that much.. Seeing as though the GPSrs are all off by a few feet anyway, it's not going to make a hill of beans difference to a geocacher. As for your questions about the sats moving... Did the moon move an inch, too? Furthermore, if the earth moves an inch, and everything around it -hypothetically- moves an inch, you won't notice any movement since both will have moved together. Quote Link to comment
+BadAndy Posted January 18, 2005 Share Posted January 18, 2005 the poles move regularly. any large geological event changes the earth's wobble slightly. you probably won't notice, unless you're one of the lucky few whose job it is to monitor the exact location and to move the ceremonial pole marker. Good thing they have a GPS to tell them where the new spot is. Good thing they use a sportrak for the job Quote Link to comment
+The Puzzler Posted January 18, 2005 Share Posted January 18, 2005 This is horrible. This is auful. All our maps are wrong now!! Of course, if the GPS satellites didn't move, we should be okay because they should still navigate according to the old model of the globe which is the one all our now defunct maps still reference. BUT, it gets worse. If the earth has changed its speed of rotation by 2.6 microseconds per day, and GPS accuracy is +/- ~1 ft per nanosecond (1/1000 of a microsecond) of clock error, then our GPSr could be off by 2600 ft per day. Maybe it's time to Quote Link to comment
+shunra Posted January 18, 2005 Share Posted January 18, 2005 i think the magnetic poles are still where they used to be. Magnetic poles actually move much faster, all the time. When you look at a topo map and it tells you what the angle is between True and Magnet North, it will usually mention the year, and how much you'll have to add or subtract as time goes by. Quote Link to comment
+shunra Posted January 18, 2005 Share Posted January 18, 2005 Your compass electronic or not, points at magnetic north (more or less). I think you're wrong about that. Electronic compasses point to the True North. Anyway, all GPSrs are obsolete now. I am opening a recycling plant. Please send me your old units for processing. Quote Link to comment
+WeightMan Posted January 18, 2005 Share Posted January 18, 2005 You forgot the $5 processing fee. What is wrong with you? Quote Link to comment
+sTeamTraen Posted January 18, 2005 Share Posted January 18, 2005 BUT, it gets worse. If the earth has changed its speed of rotation by 2.6 microseconds per day, and GPS accuracy is +/- ~1 ft per nanosecond (1/1000 of a microsecond) of clock error, then our GPSr could be off by 2600 ft per day. I presume your post is intended as humour, but in case anybody's looking for the explanation: the GPS satellites don't calculate their time by seeing how long it takes the earth to rotate... Quote Link to comment
+as77 Posted January 18, 2005 Share Posted January 18, 2005 (edited) The tweak in the earths wobble does move the mass/gravity well/whaever you want to call it so the chanbe wobble if pronounced enough might cause a slight tweak to the satalites orbit. No, the center of mass of the Earth cannot move because of an earthquake. (Conservation of momentum!) And it's only the center of mass that the satellites "feel". Actually, that's not entirely true because they can also feel the Earth's rotation through the relativistic effect called frame-dragging. But that's so minute scientists are still working to demonstrate its existence (see Gravity Probe B ). Edited January 18, 2005 by as77 Quote Link to comment
+flask Posted January 18, 2005 Share Posted January 18, 2005 i think the magnetic poles are still where they used to be. Magnetic poles actually move much faster, all the time. When you look at a topo map and it tells you what the angle is between True and Magnet North, it will usually mention the year, and how much you'll have to add or subtract as time goes by. ah. but at least tell me this: is movement of the magnetic poles tied to movement of geographical poles? Quote Link to comment
+Poindexter Posted January 18, 2005 Share Posted January 18, 2005 bugel-shunra Posted: Jan 18 2005, 02:25 AM I think you're wrong about that. Electronic compasses point to the True North. Electronic compasses work by sensing the earths magnetic field just like any other compass and so they point to magnetic north. You may be thinking of gyrocompasses which point to true north. Quote Link to comment
+Poindexter Posted January 18, 2005 Share Posted January 18, 2005 Renegade Knight Posted: Jan 17 2005, 10:10 PM They wouldn't move with it since they are not physically connected. The earth rotates at approx 1,000mph so if I jump up in the air and am no longer physically connected to the earth...yeehaaa!!! Quote Link to comment
+as77 Posted January 18, 2005 Share Posted January 18, 2005 Electronic compasses work by sensing the earths magnetic field just like any other compass and so they point to magnetic north. They can correct for the declination and thereby point to true north. Quote Link to comment
+as77 Posted January 18, 2005 Share Posted January 18, 2005 Renegade Knight Posted: Jan 17 2005, 10:10 PM They wouldn't move with it since they are not physically connected. The earth rotates at approx 1,000mph so if I jump up in the air and am no longer physically connected to the earth...yeehaaa!!! If the speed of the rotation changed while you are in the air, your speed would not change together with it. Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 Your compass electronic or not, points at magnetic north (more or less). I think you're wrong about that. Electronic compasses point to the True North.... They sence the magnetic influence lines (or whatever the heck the name for them is called) A GPS would have a built in declination table and could (or should) be able to point at true north based on the table, or magnetic north depending on your settings. With a standard compass you have to allow for the declination to find True North. I like your idea about GPS Recyling. Quote Link to comment
+shunra Posted January 18, 2005 Share Posted January 18, 2005 Your compass electronic or not, points at magnetic north (more or less). I think you're wrong about that. Electronic compasses point to the True North.... They sence the magnetic influence lines (or whatever the heck the name for them is called) A GPS would have a built in declination table and could (or should) be able to point at true north based on the table, or magnetic north depending on your settings. With a standard compass you have to allow for the declination to find True North. OK, thanks for the correction, RK and Poindexter. Learned something... Quote Link to comment
+shunra Posted January 18, 2005 Share Posted January 18, 2005 You forgot the $5 processing fee. What is wrong with you? dadgum. Why didn't I think of that. I'll accept it as voluntary contribution. Let's call it Premium Membership of my GPS recycling program. Quote Link to comment
+The Puzzler Posted January 18, 2005 Share Posted January 18, 2005 They sence the magnetic influence lines (or whatever the heck the name for them is called) Magnetic field lines. ah. but at least tell me this: is movement of the magnetic poles tied to movement of geographical poles? The magnetic poles are caused my the circulation of the earth's "liquid" interior, which is certainly affected by the possition of the spin axis (N & S poles). However, I would be surprised if the earth's mantle circulation responded measurably to such a minor change in the spin axis and even more surprised if the response time was faster than a few decades. But alas, I am not a geologist, and am only speculating. Quote Link to comment
+CoolBreeze2513 Posted January 18, 2005 Share Posted January 18, 2005 You forgot the $5 processing fee. What is wrong with you? dadgum. Why didn't I think of that. I'll accept it as voluntary contribution. Let's call it Premium Membership of my GPS recycling program. And don't forget about the $10 shipping fee....lol Quote Link to comment
+Smitherington Posted January 18, 2005 Share Posted January 18, 2005 And the processing fee. Say 7.95 Quote Link to comment
+Renegade Knight Posted January 18, 2005 Share Posted January 18, 2005 ...Magnetic field lines.... ...However, I would be surprised if the earth's mantle circulation responded measurably to such a minor change in the spin axis and even more surprised if the response time was faster than a few decades. But alas, I am not a geologist, and am only speculating.... Thanks, I've been awhile since I got to play with them in physics lab. Your speculation sounds right. It's like trying to spin a fresh egg. Given time the middle will catch up to the change in spin pattern. Until then it does goofy things. Spinning is also an easy test for which egg is the hard boiled one for when they get mixed up with the fresh ones. Quote Link to comment
PicksClan Posted January 18, 2005 Share Posted January 18, 2005 You guys are killing me here. You're either absolutely brilliant ... or simply a bunch of mad scientists Quote Link to comment
+sept1c_tank Posted January 18, 2005 Share Posted January 18, 2005 ...Spinning is also an easy test for which egg is the hard boiled one for when they get mixed up with the fresh ones. Wow! That'll save me the mess next time that happens! Quote Link to comment
+Mr Hedgehog Posted January 18, 2005 Share Posted January 18, 2005 nasa moved the north pole an inch. Right, as GPSrs are now obviously useless, I'll atruistically open a GPSr recycling centre. Send me all your GPSrs and I promise to recycle them carefully, probably via EBay Quote Link to comment
+Stunod Posted January 18, 2005 Share Posted January 18, 2005 nasa moved the north pole an inch. Right, as GPSrs are now obviously useless, I'll atruistically open a GPSr recycling centre. Send me all your GPSrs and I promise to recycle them carefully, probably via EBay Is there an echo in here? *here?* *here?* Quote Link to comment
+RJFerret Posted January 18, 2005 Share Posted January 18, 2005 That's how giant scientists determine if planets are hard-boiled too, briefly stop their spin and let go--if they spin again they've got liquid cores! Since we know the magnetic poles have reversed before (which apparently was a gradual thing, not an instantaneous thing), but the Earth's rotation has been generally consistent--it's obvious the magnetic poles don't move with the geographic poles. Astronomically speaking, Polaris has only been the north star for a few thousand years. Astrologically speaking, none of the astrology signs line up with those constellations at those times anymore! Enjoy, Randy Quote Link to comment
+Mr Hedgehog Posted January 18, 2005 Share Posted January 18, 2005 Ok, note to self. Read more than the first couple of posts in a thread before posting. Quote Link to comment
+OienLabs Posted January 18, 2005 Share Posted January 18, 2005 (edited) See Link: Quake may have altered Earth's rotation Poles are wobbling with up to 33 feet. No wonder I'm a little bit unsteady from time to time. Edited January 18, 2005 by baø Quote Link to comment
dead_white_man Posted January 19, 2005 Share Posted January 19, 2005 I heard that dick cheney made a secret deal with Haliburton to set off a nuke and move the north pole back where it belongs! Quote Link to comment
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