In an earlier video, we explored the movement of the Sun, Earth, and moon. As you know, the Sun rises in the east everyday. But this location in the east shifts throughout the year. This is clearly visible in the animation captured on Stellarium. This shift is mainly due to the tilted axis of the Earth. Let us try to understand the shift in this rising location with the help of a model. This plate mounted with gears can be rotated by hand. Gears ensure that the axis of the earth orients properly. Spoke acts as an axis of the Earth, tilted at an angle. Observe orientation of the axis as we rotate it once. This large ball is our Earth. We will mount another phone on the large ball. Camera on this phone will capture the position of the sun as it rises on the horizon in the morning. Flashlight of the phone will act as our Sun. Let us place it in the centre. Here is how months are arranged on the dial. 21st March - Vernal Equinox 21st June - Summer Solistice 23rd Sept - Autum Equinox 22nd Dec - Winter Solstice Let us start from the 21st of March . Vernal Equinox. Days and nights are equal . 21st June - Longer days and shorter nights in the northern hemisphere. 21st Sept - Another Equinox - days and nights are the same. 21st Dec - Longer nights and shorter days in the Northern Hemisphere. Let us start with 21st March. Sun rises at this location . Left frame shows the top view while the right frame shows the sunrise as seen from the Earth. As earth revolves around the sun, Sun continues its Northward journey. On 21st June, it has reached its extreme position on the North side. From this day onwards it starts its southward journey, popularly known as Dakshinayan. Let us view the location from where the sun rises at these locations. On 21st Sept, it is at the same position as that of 21st March. This is also the autumn equinox. It continues its southward journey till 22nd Dec. Now it is at its extreme position . Sun will start its Northward Journey from this day. This is also known as Uttaryan. Sun rises again at the same location on 21st March. Here is a snapshot of all the locations as seen from earth for your reference. During this capture, we placed our camera on the equator. It will be interesting to view the sunrise from other locations throughout the year. Just like sunrise, you can try sunsets as well. If the earth didn't tilt, every day would be an equinox, as the sun would always be closest to the equator. There would not be winters or summers as we know them, How about different tilt angles for the Earth's axis. Give it a try. Have a nice time. Thank You.

• published: 28 May 2022
• views: 39310