December 21, 2021 2:30:39 pm
Today, December 21, is marked as the Winter Solstice, during which the Northern Hemisphere experiences the shortest day and longest night of the year. Today, the angle of the sun’s rays will be perpendicular to the earth at the Tropic of Capricorn.
Our Earth tilts on its axis at 23.5 degrees and as it revolves around the Sun, it rotates on its axis. On December 21, the Northern Hemisphere tilts the farthest away from the Sun and this is known as the winter solstice. After the winter solstice, the days will get longer and the nights shorter in the Northern Hemisphere, until June 21, 2022 (the summer solstice) and things will reverse.
According to NASA, the December solstice will start today at 15:59 UTC or 21:29 IST.
The Public Outreach and Education Committee of the Astronomical Society of India has shared a fun activity that you can do at your homes tonight.
We are back with our shadow measurement experiment. Send us your results.
For details: https://t.co/kEWkK2pEMF
— Astronomy outreach (@asipoec) December 20, 2021
You would need only a magnetic or digital compass. Start your observation just before sunset. Use your compass to face West and watch the horizon carefully. Keep the compass at eye level and watch the sun as it starts to go down to the horizon at sunset. You will notice that the sun doesn’t set exactly in the West.
On your compass, measure the difference in angle of the sunset from West and share your data on this Google form.
Why the difference in angle?
The December solstice is the southernmost sunset point.
After this, the sunset point starts moving North. The angle you measure today from East at sunrise (or from West at sunset) is the southernmost rising (or setting) point of the sun for your location.
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