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( Compass)
A compass is a navigational instrument for determining direction relative to the Earth's magnetic poles. It consists of a magnetized pointer (usually marked on the North end) free to align itself with Earth's magnetic field. The compass greatly improved the safety and efficiency of travel, especially ocean travel. A compass can be used to calculate heading, used with a sextant to calculate latitude, and with a marine chronometer to calculate longitude. It thus provides a much improved navigational capability that has only been recently supplanted by modern devices such as the Global Positioning System (GPS). A compass is any magnetically sensitive device capable of indicating the direction of the magnetic north of a planet's magnetosphere. The face of the compass generally highlights the cardinal points of north, south, east and west. Often, compasses are built as a stand alone sealed instrument with a magnetized bar or needle turning freely upon a pivot, or moving in a fluid, thus able to point in a northerly and southerly direction. The compass was invented in ancient China sometime before the 2nd century, and was used for navigation by the 11th century. The dry compass was invented in medieval Europe around 1300.[1] This was supplanted in the early 20th century by the liquid-filled magnetic compass.[2] Other, more accurate, devices have been invented for determining north that do not depend on the Earth's magnetic field for operation (known in such cases as true north, as opposed to magnetic north). A gyrocompass or astrocompass can be used to find true north, while being unaffected by stray magnetic fields, nearby electrical power circuits or nearby masses of ferrous metals. A recent development is the electronic compass, or fibre optic gyrocompass, which detects the magnetic directions without potentially fallible moving parts. This device frequently appears as an optional subsystem built into GPS receivers. However, magnetic compasses remain popular, especially in remote areas, as they are cheap, durable, and require no electrical power supply.[3] Prior to the introduction of the compass, position, destination, and direction at sea was primarily determined by the sighting of landmarks, supplemented with the observation of the position of celestial bodies. Ancient mariners often kept within sight of land. The invention of the compass enabled the determination of heading when the sky was overcast or foggy. And, when the sun or other known celestial bodies could be observed, it enabled the calculation of latitude. This enabled mariners to navigate safely far from land, increasing sea trade, and contributing to the Age of Discovery Based on his find of an Olmec hematite artifact in Mesoamerica, radiocarbon dated to 1400-1000 BC, astronomer John Carlson has suggested that the Olmec might have discovered and used the geomagnetic lodestone compass earlier than 1000 BC. If true, this "predates the Chinese discovery of the geomagnetic lodestone compass by more than a millennium".[4] Carlson speculates that the Olmecs used similar artifacts as a directional device for astrological or geomantic purposes. The artifact is part of a polished lodestone bar with a groove at one end (possibly for sighting). The artifact now consistently points 35.5 degrees west of north, but may have pointed north-south when whole. Other researchers have suggested that the artifact is actually a constituent piece of a decorative ornament.[5] No other hematite artifacts have been found.
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Compass Subcategories
Compass Articles
Secret Science of Weight Loss by Jayden Smith
We no longer require proof that the majority of America is either overweight or obese, most of us are. Our nation is more than a billion pounds over the ideal fat threshold and that number is climbing to uncharted astronomical proportions da...
Best Skin Care - How To Choose Skin Care Products USA by Animesh Pal
Everyone give skin care advice, yet somewhere in the jumble of promises and miraculous claims, your best skin care product is waiting to be discovered. Since it's not going to call your name or jump in your shopping basket, how do you find the perfec...
How To Choose Skin Care Products by Animesh Pal
Everyone give skin care advice, yet somewhere in the jumble of promises and miraculous claims, your best skin care product is waiting to be discovered. Since it's not going to call your name or jump in your shopping basket, how do you find the perfec...
How To Choose Natural Skin Care Products by Animesh Pal
Everyone give skin care advice, yet somewhere in the jumble of promises and miraculous claims, your best skin care product is waiting to be discovered. Since it's not going to call your name or jump in your shopping basket, how do you find the perfec...
Best Skin Care - How To Choose Skin Care Products by Animesh Pal
Everyone give skin care advice, yet somewhere in the jumble of promises and miraculous claims, your best skin care product is waiting to be discovered. Since it's not going to call your name or jump in your shopping basket, how do you find the perfec...
Thoughts About Attitude by Colby Morrison
Success is in the blood. There are men whom fate can never keep down they march forward in a jaunty manner, and take by divine right the best of everything that the earth affords. But their success is not attained by means of the Samuel Smiles-Connec...
The Culture of Overeating: A Survival Guide by John Manjarres
When it's all said and done, they accumulate on your body in the most obtrusive way as a result of dozens of unused calories.
Why does food hold such power? And, most importantly, how can you control your eating?
The End of Overeating...
Understand The Hazards Of Mountain Climbing by Joan Shine
Mountains are a perennial favorite for group hikes and picnics because nowhere else can you be treated with spectacular views and exciting adventures. But with all their stunning beauty and potential for fun and enjoyment, mountains also pose hazards...
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