Is the earth’s axis always in the same plane? Does the tilt stay the same? What does this effect?

1 Answer
Oct 28, 2016



A line is an 1-D space. Plane is a 2-D space and the Earth is a 3-D

space. Two lines (in same or different directions ) determine a plane

Earth's axis is a #straight# line parallel to the ( the little away ) polar

axis. So, relatively, both are coplanar..

Over a period of Great Year (nearly 25800 years), the polar axis

moves ( relative to the Earth ) along the surface of a cone of semi-

vertical angle #23.4^o#, keeping its direction relative to the normal

to the ecliptic as the same #23.4^o#. This is called precession

motion. The average variation (#+-0.00006^o#/year, in the range

from #22.04^o# through #23.44^o# to #24.50^o#, over a period of

about 41 K years ) of this angle, about the mean 23.27^o. is nearly 0,

Of course, poles move but its precession and nutation ( nodding

across ) are incognizant.