Ecuador has a monument on the equator, and Greenwich, UK has a line on the ground representing the prime meridian. Suppose a country on the arctic circle or the tropic of cancer proposes a monument on their respective significant latitude lines. How feasible is it?
If the tilt of the earth's axis (obliquity of the ecliptic) is changing at about 47 arc seconds per century, how far would the monuments have to move each year?
arc length = dist x angle subtended [Rad]
yearly displacement
d' [m/year]= R x 47 arcsec / century (R is radius Earth)
= 6.31 10^6 [m] x [pi Rad/180 deg] [Rad/deg] 47 [arcs/cent] x
1/3600 [arcs/deg] x 1/100 [cent/yr] = 14.51 [m/yr]
(In fact many - some moving, some not - see the wiki photos)
Note - if you track the pole position in time (the so called Chandler Wobble) in polar coordinates about a polar centroid, the radial differences translate into longitudinal displacement of the circles (equator, arctic, etc.) more directly than does the azimuthal progression.
Edited on July 10, 2023, 12:30 pm
soln
_Zaragoza-Victoria,_Km_27+800.jpg){kind=link}