Question

What does precession of the equinoxes mean?

Answer 1

See explanation

Explanation:

Precession of equinoxes:

Equinox is an instant of time in a year, at which the line of centers of

the Sun and the Earth crosses the equator, in exactitude. The event

occurs twice in a year. The one on about March 21 is called vernal

equinox and the other occurring half year later, by about September

23, is called Autumnal Equinox.

At this equinox location on the equator,

the noon Sun will be right overhead, casting no shadow at all.

The Earth's axial precession, with the period of nearly 258 centuries,

moves this location, longitudinally, by about `360/25800=(1/72)^o`,

nearly, every year.

Also, this equinox-noon-time is delayed by 24 h in 25800 y, which

is `(24 X 3600)/25800 = 3.35 sec`, every year of 31557600

seconds.

These related movements of equinoxes on the equator, with respect

to location and time, is called precession of equinoxes..