How did the earlier explorers know exactly when they reached the North or South Pole.?
408419
Perry (the first man to reach the pole) used dead reckoning and solar navigation.  Because the sun never sets during the summer, you can't navigate by the stars in polar regions unless you go during the winter, which is a bad idea.\n\nAnywhere north of the tropics, at noon, your shadow points due north.  Perry used this as the basis for his navigation. Once you know which way north is, you can adjust your compasses appropriately. (The magnetic north pole is hundreds of miles or so from the real north pole, so compasses point in the wrong direction, but don't spin wildly, near the north pole.)\n\nThese navigation techniques left some room for doubt, and there have been long controversies as to how close to the pole many of those explorers got.  The source below is a really interesting article on one of those stories.
194469
There are three types of North to consider.\n\nMagnetic north is determined by the Earth's magnetic field. This point moves considerably wandering in an eliptical path on a daily basis, and moves even more over a period of decades. On average it moves 10 km per year. Because of this all maps require a correction to be made for the reading of a compass in order to match the map. This is known as declination, also called magnetic declination. Declination also varies according to variations in the Earth's magnetic field in different geographic areas.  In order to use a magnetic compass to navigate with a map you must know your local declination value. \n\nTrue north is determined by the celestial North pole, which is the term used by navigators for the position of the star Polaris. This point will only be useful for about another thousand years because of the precession of the Earth during its orbit. Precession could be described as a wobble in the Earth's axis of rotation. \n\nCelestial north, or grid north is the point where the earth's spin axis hypothetically extends through the earth. Relative to our position on the planet this does not change because it is essentially an arbitrary point decided on by cartographers. However it is not consistent from one geographic coordinate system to another. This is because a globe is the only way to accurately represent all points on the earth and a map using any two dimensional coordinate system will have errors in some part of the map.
272155
When I teach this subject my answer is always three fold.  FIRST-ancient peoples crossed over the land bridge between Asia and North America.  \n\nSECOND-Leif Erikson was the first known European to discover America\n\nTHRID- Columbus "rediscovered" America at a time when the knowledge caught hold and became widely known. \n\nMy personal belief is that many people discovered it independantly of others and thus were the true "first discoverer" at least in their own minds eye (and tribes or ships).
228548
Apart from the North Pole, there is a countable infinity of circumferences parallel to the equator, in which each point has this property. They are:\n- The circumference which distance from the South pole (> 1 mile) is such that when you go 1 mile south and then east, you run on a smaller closed circle exactly 1 time (it is long 1 mile), so that you hit the same point and go up via the same meridian.\n- The circumference in which the construction above leads to a smaller circle exactly 1/2 miles long.\n- ... and so on, with 1/3, 1/4, 1/5, etc.
617590
Carl Wilhelm Scheele discovered it in 1772, and Joseph Priestly found it in 1774 (independently).  Scheele was a Swede, Priestly was an Englishman.
1135657
If it is in reference to the Antarctic research area, then I believe you can find information in http://www.smitha.demon.co.uk/zfids/ on this page, there are links that let you know about the progress of the area since 1956 to this day –there are pictures too. In addition, I believe you can find it in Wikipedia too and work from there. Make sure you visit the external links; they might be able to provide you with important information. Good luck with the assignment ;)
209485
1)In the space there is no direction.So it matters not what direction you call by what name.\n2) On the Earth , on the other hand , it does matter and matters a lot; and the reasons are too obvious to quote.\n3) On the earth the bearings are taken with the help of fixed stars in the Sky and it has no racial bias.\n4) In this context the POLAR STAR acquires importance. The North pole of the earth is directly pointing towards this unmoving star in the sky. So much so that if you are standing exactly on the north pole, the Pole star or the North Star will be directly above you and the angular distance between you and the star will be Zero. That is exactly how the polar expedition leaders find out if they have reached their goal correctly or not.\nAs you move towards the South pole the angular distance increases to reach 180 degrees and the pole star disappears from your sight.
240306
The way the stick points to is always North.  Aline your compass so that the "N" (or North) is pointing there, and you know where East, West and South is now.  Along with all the little things inbetween.  :)
89051
On average, about once every 250,000 years or so Earth's two magnetic poles switch---the north magnetic pole becomes the south magnetic pole, and the south magnetic pole becomes the north magnetic pole. This means, among many other things, that compasses would all point south instead of north.\n\nScience knows that these pole reversals do happen. Some ancient rocks tell the story. In the far distant past these rocks were molten. At those times their interior materials would align themselves to Earth's magnetic field, much the way an electromagnet will. Careful analysis shows that the magnetic lines of force imbedded in these rocks often were directly opposite to Earth's present magnetic field.\n\nThe last pole reversal happened some 700,000 years ago, so we're sort of overdue for another one.
470171
The polar diameter of the earth is 12,714 km.  So the actual distance between the north and south pole is 12,714km.  The meridional of the earth is 40,008 km (the circumference going around the poles).  So, if you walked, you would walk at least 20,004 km from North to South pole.
585209
Its not so much one pole attracting the needlepoint so much as the entire magnetic metal beneath the needle aligning to the magnetic field lines*. North and South are just directional names; the most powerful magnet at the time magnetism was discovered was the earth, so naturally, they used the locations of the Earth's poles to name every magnet's pole.\n\n*Magnetic field lines are lines of force connecting the North and South poles of every magnetic object. Place a magnet under a piece of paper and sprinkle iron filings on top, and you'll be able to 'see' them. \n\nThe magnetosphere is the name given to the Earth's magnetic field, which extends into space and gives us protection against much of the charged particle radiation from the sun. This 'solar wind' interacting with our magnetosphere is what causes the auroras over the poles.
591596
Funny thing is, every century this comes up. People changing their lives because the date corresponds to 666 are full of whooey. 600 years ago everyone knew the world was flat. 300 years ago everyone knew Earth was the center of the galaxy. And today, you know everything isn't going to change because if some misguided beliefs. Just imagine what you'll know tomorrow.
537988
What did Drake find out on his voyage around the world?\nDrake's voyage helped to give a more accurate picture of the true geography of the world. During the course of the voyage, Drake discovered that Tierra del Fuego, the land seen to the south of the Magellan Strait, was not part of a southern continent as had been believed previously, but an archipelago, or group of islands. Francis Fletcher, the chaplain on Drake's ship described it like this:\n\nIn passing along we plainly discovered that same Terra Australis to be no continent, but broken islands and large passages amongst them....\n\nThis meant that if the American continent was not connected to a southern continent, the Pacific and the Atlantic oceans met at Cape Horn. It should be possible to sail ships around the bottom of South America, south of Tierra. This was the Cape Horn route, eventually discovered in 1616.
984752
Latitude is "imaginary" lines that run around the earth PARALLEL to the equator. They represent degree from the equator to the poles.  For example, the equator is also the zero degree latitude line; the north pole is at 90 degrees or at 90 degrees North Latitude; the south pole is at -90 degrees or 90 degrees South Latitude.  Everything in between can be referenced to these values.\n\nLongitude lines are imaginary lines running from the north pole to the south pole.  These lines are farther apart at the equator and get closer as they approach the poles where they converge (or come together).  Longitudes are usually referenced from Greenwich, England where it has been established as Zero Degrees longitude.  There are 360 degrees (i.e., a complete circle) around the earth, but generally is referenced as 180 degrees East of Greenwich (or +180 degrees) or 180 degrees West of Greenwich (or -180 degrees).\n\nThe degrees are further divided in minutes and seconds, so that there are 60 seconds in a minute and 60 minutes in a degree.  So one might reference a spot as being 35 degrees, 10 minutes, 22 seconds North (often written as 35 deg 10'  22") and 96 degrees, 6 minutes, 30 seconds West (96 deg 6' 30").  \n\nOr those same numbers might be should strictly as decimal degrees such as (using the same example): 35.17278N, 96.10833W.
1103752
North is one of the four cardinal directions, specifically the direction that, in Western culture, is treated as the primary direction: north is used (explicitly or implicitly) to define all other directions; the (visual) top edges of maps usually correspond to the northern edge of the territory represented, unless explicitly stated otherwise or landmarks are considered more useful for that territory than specific directions\n\n\n\nTRUE north, the direction along the earth's surface toward one pole of the earth's rotation, namely the pole that is clearly on one's left when standing at the Equator while facing the rising sun.\n\nMAGNETIC north, the direction along the earth's surface in which horizontal magnetic field strength has its most positive value (but see Flipping of planetary magnetic poles for an eventual event, so rare as to make unlikely any advance agreement on whether one or two retronyms would be involved in the replacement terminology)\n\nSouth is also  one of the four cardinal directions or compass points. It is the opposite of North and at right angles to East and West.SO ONCE NORTH IS FIXED SOUTH IS IT'S OPPOSITE\n\nBy Western convention, the bottom side of a map is South.\n\n\nSo, the real answer to your question is that it's just a convention & has no scientific basis behind it .
926113
The Earth is tilted at an angle of about twenty three and a half degrees.  This is the reason why North and Magnetic poles are not at the same place.  \n\nAnyway, in the Northern winter, the North Pole is angled away from the Sun, with the South Pole therefore being angled towards the Sun.  The result is 24 hours night in the north, 24 hours day light in the south.  This is the southern summer.\nNow remember that the Earth maintains this angle throughout its orbit.\nSix months later, the Earth is on the other side of its orbit around the Sun.  Still maintaining the same tilt, now the North Pole is receiving 24 hour day light, and the South Pole is in darkness.  Northern summer, southern winter.\n\nThe Arctic and Antarctic circles mark the limit of this 24 hour daylight, and the Tropic of Cancer (North) and the Tropic of Capricorn (South) mark the limits of the maximum travel of the Sun at it appears in the northern and southern skies.\n\nAt the Spring and Autumn exquinox, the Earth is such that the Poles are receiving equal amounts of sunlight.  Equinox means "equal night".  \n\nI down know any particular websites but try the NOAA and BBC weather sites.\n\nADDITION: To Glenn Blaylock.  Thank you very much for the correction.  I'll read up on my error.
935938
They have used the paralax method since about that time.  This is measuring the arc of items in space with known distances.  They have known diamater of the earths rotation 186,000,000 for a long time.  Knowing that it is possible to measure the distance of astronomical items using one second of angle in the difference of an items location in the sky measured six months apart.\nB