Answer to Question #104914 in Astronomy | Astrophysics for Rakesh kumar

Question

With the help of the clear and labelled diagrams show the change of seasons on earth resultant from the tilt of its axis of rotation.

Answer 1

The amount of solar radiation that heats our planet up depends on the angle between Earth's surface and the beams of light. For example, when rain falls perpendicularly to some surface, the surface "collects" the highest number of raindrops. When the angle between the surface and the raindrops is 0, no drops hit the surface. Same with the sunlight. Look:

The summer in the northern hemisphere (on the right) corresponds to more rays directed to the surface at 90 degrees angle. Meanwhile in the southern hemisphere the angle between the surface and the light is smaller, that is why the insolation is decreased as well. So, we can write the amount of solar energy that reaches the surface as

$$E_\text{Earth}=kE_\text{Sun}\text{ sin}\alpha.$$