Name: Eric
Status: Student
Grade: 9-12
Location: NY
Country: United States
Date: September 2007
Question:
Regarding the tilt of Earth; It is said that it goes
back and forth between 21 and 25 degrees than back to 21 degrees.
Why does it go back? Wouldn't it continue to 26 degrees and further?
Could that occur or is it certain that it goes back?
Replies:
Eric,
The orbit of the Moon, its close proximity of
orbit around Earth, and their combined gravitational
forces limit the extent of tilt of the Earth, in a manner
similar to the rotating part of a gyroscope keeping
the entire device upright.
The tilt follows approximately a 41,000 cycle,
partially due to the Earth not being a perfectly
balanced sphere.
David R. Cook
Meteorologist
Climate Research Section
Environmental Science Division
Argonne National Laboratory
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