How does the tilt of Earth's axis affect how the sun's rays strike Earth?

1 Answer
Sep 2, 2016

See explanation.

Explanation:

At any instant , the Sun-facing hemisphere of the Earth

has a zenith and a nadir.

The latitude difference for these points is nearly #180^o#.

If there is no tilt, the line of centers of the Earth and the Sun will

pass through the equator of #0^o# latitude. So, Sun's rays will

strike normal to the equator, casting no shadow at all, at every noon.

Elsewhere, the angle of in incidence of these ( parallel ) rays will

be the latitude, for ever.. Noon-shadow length will be

(vertical height) X tan (latitude ). Latitude is #90^o#, at either

pole, wherein the Sun will be at the horizon, for ever.

The tilt of #23.4^o#causes the oscillation of the solar rays between

the angles of incidence

#latitude - 23.4^o and latitude + 23.4^o#,

during the orbital period of one year. This causes local seasons.. .