The North Star, the star that is located directly above the Earth’s rotation axis is called, Polaris. Interestingly, this star hasn’t always been our North Star and will one day be replaced by a star called, Vega. In fact, the star Thuban was our North Star 5,000 years ago before Polaris moved into place. Why does this happen?

In order to get a better sense of this phenomenon called Precession, think about a spinning top as it rotates. It doesn’t spin with complete uniformity, it sort of wobbles around the point in which it touches the surface.

Picture planet Earth doing this same thing in space. It is rotating, like the spinning top but “only” at 1,000mph. As it rotates on its axis, it is subject to something called, torque which is a twisting force on Earth’s axis caused by the gravitational pulls of the Sun and the Moon. This movement of Earth about its axis occurs during a cycle of roughly 26,000 years. It is in 12,000 years that Vega will replace Polaris. Your genes hopefully pass through 150 generations so a part of you will be around to see this happen :)

61 notes
Posted on Wednesday, 15 August
Tagged as: space science astronomy precession
Next Post Previous Post
  1. dj-phr0 reblogged this from astrodidact
  2. ken-incorporated reblogged this from astrodidact
  3. malphalent reblogged this from believe-in-science
  4. sfphysics reblogged this from starstuffblog
  5. galaxiesspinperfectly reblogged this from believe-in-science
  6. renach reblogged this from astrodidact
  7. cataclysmicnightmare reblogged this from astrodidact
  8. istellar reblogged this from astrodidact
  9. boringmaureen reblogged this from imagineatoms
  10. believe-in-science reblogged this from imagineatoms
  11. imagineatoms reblogged this from starstuffblog
  12. starstuffblog reblogged this from astrodidact
  13. insidious-gestalt-aggregation reblogged this from astrodidact
  14. bruines reblogged this from astrodidact and added:
    The North Star, the star that is located directly above the Earth’s rotation axis is called, Polaris. Interestingly,...
  15. kiltedken reblogged this from astrodidact
  16. leadmetoinsanity reblogged this from astrodidact
  17. butt-hut reblogged this from astrodidact
  18. purplecosm0naut reblogged this from astrodidact
  19. temptingtimeonimpulse reblogged this from astrodidact
  20. rockman63 reblogged this from astrodidact
  21. alexandria-thegreat reblogged this from astrodidact
  22. rawnova reblogged this from astrodidact