December 21 is marked as the winter solstice during which the Northern Hemisphere experiences the shortest day and longest night of the year. On that day the direction of the sun’s rays are vertical to the earth at the Tropic of Capricorn.

Also Read: 13 fascinating winter solstice traditions around the world

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 i.e. the summer solstice and then, things will reverse.

Also Read: Winter wonderlands to visit in India to cozy up with your significant other

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 have shared a fun activity that you can do at your homes tonight. You only need a magnetic or digital compass. Then start your observation just before the 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.

Also Read: Summer solstice: All about the longest day of the year

The December solstice marks 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.