Understand why the Earth has a summer, and a winter season.
If you live in India, you know summer arrives when Holi is over. That’s the signal to stop taking warm water baths and go for cold showers. Then we sweat it through the next few months, eating mangoes, enjoying the summer vacation…and slowly in time, the heat reduces. And then Diwali comes around and it’s pretty cold, so out come sweaters. The winter season is now upon us.
So what causes Earth to change it’s seasons? To understand this, you have to know two things:
The Earth spins around an imaginary line, called the axis, that goes through the center of the earth and emerges out the north and south poles.
This axis is tilted by about 23.5 degrees.
It’s really the second point that causes the seasons. When the northern hemisphere is tilted towards the sun, it receives sunlight directly that causes it to be concentrated in a smaller area, so the whole area heats up. When the northern hemisphere is tilted away from the sun, the sunlight now falls in at an angle and is spread over a larger area…so the whole area feels cooler.
This whole process is very beautifully explained in this video.
There are two misconceptions to clear up:
The seasons is due to the revolution of the Earth around the Sun. It’s explained in the video above, but here you can see the commonly seen, but completely incorrect orbit of the motion of the Earth around the Sun. The earth’s orbit is elliptical, but not that elliptical. In the picture below, it appears as though it’s summer when the Earth is near the sun, and winter when it’s far away. Not really, and this leads us to the next misconception…
That when it’s summer in India, it’s summer all around the world. Not really. In Australia, winter starts in June, just as you are about bite into that hot summer mango in India.
Happy summer, or winter depending on where you live right now!