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About North Star

Context:

Vice President said Parliament is the “North Star” of democracy, “a place of discussion and deliberation to realise the aspirations and dreams of the people”.

Relevance:

GS I: Geography

Dimensions of the Article:

  1. About  North Star
  2. When was the North Star first used to navigate?
  3. Literary metaphor

About North Star

  • Polaris, also known as the North Star or the Pole Star, is a very bright star (around 2500 times more luminous than our sun) placed less than 1° away from the north celestial pole.
  • Its position and brightness have made humans use it for navigation since late antiquity.
  • It is a part of the constellation Ursa Minor and is around 323 light-years away from Earth.
  • Since Polaris lies nearly in a direct line with the Earth’s rotational axis “above” the North Pole, it stands almost motionless in the night sky, with all the stars of the northern sky appearing to rotate around it.
  • This makes it an excellent fixed point from which to draw measurements for celestial navigation.
  • Simply the elevation of the star above the horizon gives the approximate latitude of the observer and in the northern hemisphere, if you can see Polaris you can always tell which way is north (and, by extension, which ways are south, east and west).
  • Upon crossing the equator to the South, the North Star is lost over the horizon and hence stops being a useful navigational aid.

When was the North Star first used to navigate?

  • Polaris seems to have been first charted by the Roman mathematician and astronomer Ptolemy, who lived from about 85 to 165 B.C.
  • While there does exist some evidence pointing at how the star was used for navigation in late antiquity, it is during the ‘Age of Exploration’ that it becomes such a central part of human history.
  • Christopher Columbus, on his first trans-Atlantic voyage of 1492, “had to correct (his ship’s bearings) for the circle described by the pole star about the pole”, wrote his son in his biography.
  • As European colonisers set sail for exotic locations across the world, the North Star became an ever so important feature of the night sky that allowed for remarkably accurate navigation using instruments which were still rudimentary by modern standards.

Literary metaphor

  • The first well known instance of the North Star appearing in literature outside of a technical treatise on astronomy or a biography of an explorer is in Shakespeare’s Julius Caesar, where the eponymous emperor describes himself as being “as constant as the Northern Star”.
  • However, the “constant” North Star was probably not known to the real Caesar (reign 49-44 BC).
  • Also, as the NASA page on Polaris points out, “North Star” is “a title that passes to different stars over time”. As the Earth’s axis of rotation wobbles in the same way as a spinning top, the celestial pole “wanders in a slow circle over the eons, sweeping past different stars”.
  • About 14,000 years ago, the celestial pole pointed towards the bright star Vega, and “it will again point to Vega in about 12,000 years”.

-Source: Indian Express


March 2023
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