James Rogers, of Kaiapoi Borough School, asks :-
What makes the Earth tilt away from the sun to give us longer nights in winter?
Frank Andrews, an astronomer at the Carter Observatory, responded.
You have asked a question for which we dont really know the answer.
The planets Mercury, Earth, Mars, Saturn and Neptune all seem to have the same tilt. All are between 29 and 23 degrees. (There are 90 degrees between vertical and horizontal.)
Venus at 3 degrees, Jupiter at 3 degrees and Uranus at 98 degrees seem to be the odd ones out. Uranus and Venus also have another characteristic which seems unusual. Both planets rotate in the opposite direction to the others, Uranus in 15 and a quarter hours and Venus in 243 days. Astronomers think that very early in their history Uranus and Venus may have suffered major collisions with other planet size bodies and so had their spin rate and/or the tilt of the axes altered.
As for Earth and the other planets we simply have no suggestions as to why their axes are tilted at the angles they are. There are still plenty of problems left for future astronomers to solve. If the Earth's axis had no tilt we would have the same weather all year round so I am glad there is a tilt as I like the change of seasons.