Expert: Jayendra Upadhye - 2/18/2006

Question
hello. I have two questions. Firstly, i was wondering what would happen if Earth's axis of rotation was parallel to the sun's? and secondly, what if our axis was inclined at an angle of 35 degrees to the sun's?

Answer
Josh,
Case-1:- Both axes are parallel.
then
a) - There would be no change of season for people of a given region.
b) - People on the equator would have a permanent rainy season all year round, due to the tremendous amount of water vapour extracted from the oceans by the sun.
c) - people in the tropics would see the sun progresively "to the south" in the northern tropics, and "to the north" in the southern tropics, at mid day, every day.
d) - winter would be a function of latitude only.
e) - so would summer.
g) - Rainfall would get progressively lower as one went towards the poles.
h) - the tropics would be cooler than now.
i) - "pollination patterns" in the plant world, would be lost, as there would be no discernible "spring"!
j) - animals that "come into season" (example the wilderbeast on the vast serengetti plains of africa) wouldnt know when to produce offspring!
k) - the world would be a colorless dull place.

case-ii:- inclination 35 degrees.
a) - all things you see on earth due to seasons, would be more highlighted,
b) - the polar caps would recede.
c) - There would be more rainfall further up on the tropics.
d) - the equatorial regions would have two pronounced "summers" as the sun traversed far to the north then far to the south, passing "overhead" twice in a year!
Imagine summer coming in twice a year followed by a mild but noticeable winter twice a year and also the rainy season twice a year! at the equator.

Point to note:- The lord of the system, the sun is followed by the earth's protective cloud cover wherever he goes up and down his annual pilgrimage of the tropics.
The rainy season comes to teh tropics when the sun touches them. (almost).
The higher albedo (reflectivity) of the clouds "cools" off the earth, and once the clouds drain their rain, vaporisation from the oceans further cools the earth off!
Without that the sun would kill all underneath it.
In the tropics deep inland, the temperature crosses 50 deg centigrade already!
There is an insight into the earth's regulatory mechanisms here.

Jayen