Hi Jimmy!
Hi!
Your pullover is very nice, but why are you wearing it on such a hot day?
Thanks for the compliment! I love this pullover and had to really struggle to get it from
mom.
She said that winter season is over and this pullover should be kept inside.
Even I have to wait for a few months for the rainy season so that I can wear my favourite
raincoat. Why can’t we have rainy season now?
Hmm, why do we have different seasons in different parts of the year?
This is because of Earth’s tilt on its axis and its revolution around the Sun.
How? Let me explain it to you
Axis of the Earth is an imaginary line on which the Earth rotates. It links the two
poles – North pole and the South pole. This axis and thus the Earth is tilted 23.5 degrees
relative to the ecliptic plane around the Sun. This tilt causes one hemisphere to get
comparatively closer to the Sun and receive direct sunlight, thus resulting in summer
while the other hemisphere which is comparatively farther from the sun receives slanting slanting
rays, thus less intense heat resulting in winter.
This gives us the four seasons of the year - Spring, Summer, Autumn (Fall) and Winter.
Regardless of the time of year, the Northern and Southern Hemispheres always experience opposite
seasons. There are 3 important terms to understand – Overhead Sun, Equinox and Solstice.
Oh I heard of these terms earlier but could not understand a thing.
It’s very simple. Let me explain one by one.
Overhead Sun – This is the situation when the mid-day Sun and the Earth’s surface
form a 90 degree angle. Different locations of the overhead Sun results in variations
in the amount of solar radiation received. Equinoxes are days in which the overhead
Sun is on the Equator giving day and night of equal duration at all places on the Earth.
Spring Equinox – On the 21st or 22nd of March the overhead Sun is over the Equator
making it receive maximum sunlight. On this day both the hemispheres receive a similar
amount of solar radiation and equal length of day and night at all places on the Earth
is observed. Can we observe this equinox?
Yes! On this day Sun rises in exact East and sets in exact West.
After this day there is Spring in Northern Hemisphere with longer days and shorter nights
and Autumn in Southern Hemisphere with shorter days and longer nights.
Solstices The solstices are days when the Sun reaches
its farthest Northern and Southern declinations. Summer Solstice - On the 21st or 22nd of June,
the overhead Sun is on Tropic of Cancer. On this day the Southern hemisphere is in Winter
solstice and Northern Hemisphere is in Summer solstice. At this time, Northern hemisphere
experiences summer with the day being the longest day of the year while Southern hemisphere
has winter with the day being the shortest day of the year. The Arctic circle has 24
hours of daylight on this day while Antarctic circle experiences 24 hours of darkness.
Autumn Equinox - On 22nd or 23rd of September the overhead Sun is again on Equator giving
Autumn Equinox with equal length of day and night in both the hemispheres. At this time
the Northern hemisphere experiences Autumn Equinox and the Southern hemisphere experiences
Spring Equinox. Winter Solstice – on 21st or 22nd of December
the overhead Sun is over the Tropic of Capricorn. On this day the Northern hemisphere is in
Winter solstice and Southern Hemisphere is in Summer solstice. At this time, Southern
hemisphere experiences summer with this day being the longest day of the year while Northern
hemisphere has winter with the day being the shortest day of the year. The Antarctic circle
has 24 hours of daylight on this day while Arctic circle experiences 24 hours of darkness.
This periodic phenomenon causes different seasons at different places at different times.
So it’s all about Earth’s tilt and revolution around the Sun.