How is the tilt of the earth determined mathematically?

1 Answer
Phillip E.
Dec 25, 2015

The obliquity, or axial tilt angle, is can be calculated by a power series based on observation.

Explanation:

There is a mathematical formula which can be used to determine the Earth's obliquity. It is #ε = 84381.448 - 46.815T -0.00059T^2 + 0.001813T^3#
Where the angles are in arc seconds #84381.448/3600 = 23.439°# which was the obliquity at the J2000 epoch on 2000-01-01 12:00:00. T is the number of Julian Centuries days since the J2000 epoch, which is the number of days before or after J2000 divided by 36525.

Hence the obliquity is decreasing at a rate of about 46.814 arc seconds every 36525 days.

Related questions
See all questions in The Planets
Impact of this question
1607 views around the world
You can reuse this answer
Creative Commons License