 Hello my dear friends and Chana Ki Aayi's fraternity. I, Krishnakumar, welcome you all to today's topic of discussion and today's topic of discussion is Bintal Solstice. We are going to cover each and every topic related to solstice. Watch this session very carefully. It is going to be very very very important. If you would understand the concept of solstices, then you will never face problems in questions related to the solstices. This session is going to be relevant for each and everyone who has interest in geographical phenomena. So before beginning our discussion, I would like to put forward a question related to solstices. So consider the following statements with respect to solstices. The first statement says, phenomena of solstices are associated with tropics. The second statement says, winter solstice marks the longest day and the saltest night in the northern hemisphere. Which of the statements above are correct? Your options are these. You can answer this question in the comment box if you know the answer. And if you don't know the answer, please watch this video till the end of the session and you will know each and every aspect of the solstice. So beginning our discussion, I would like to discuss why solstice is in news. December 21 was winter solstice and it is the shortest day of the year in the northern hemisphere. Day before yesterday was winter solstice as it was 21st December and it was the shortest day of the year in the northern hemisphere. In Delhi, the sun rose at around 7 am and set at 5.29 pm, making the day 10 hours. So you can see the day is being shortened and in Delhi the duration of day has reduced to 10 hours. Similarly in the southern hemisphere, the day is called summer solstice in places like Australia, New Zealand, South Africa. The December 21 is year's longest day. So in Melbourne, the sun rose at around 5.54 am on Monday and set at around 21 pm. That is the day was around 14 hours and 47 minutes long, that is around 15 hours. You can see that similarly the summer solstice in the southern hemisphere marks the longest day in the southern hemisphere. So let us understand that what is this solstice through this diagram because understanding anything through diagram is very informative and we get to know that what is the concept behind this. So we have been discussed that what are these equinoxes and solstices and how they affect the earth and geographical phenomena. This is sun and this is our earth and the earth is tilted on its axis by 23.5 degrees. So here on 21st March, the sun rays are perpendicular to equator and this brings autumn in the southern hemisphere and spring in the northern hemisphere. After that the earth will move in the anti-clockwise direction and on 21st June, there would be summer solstice. That is the sun rays would fall perpendicular to tropic of cancer. So it would mark the summers in northern hemisphere and winters in southern hemisphere and after that the earth will move further and on 21st September, there would be another equinox and this equinox would mark autumn in the northern hemisphere and spring in the southern hemisphere and moving forward the sun on 21st December would mark the winter solstice on which the sun rays will fall perpendicular to tropic of capricorn and by this the northern hemisphere will mark by winters and the southern hemisphere will mark by summers. You can see this video and see this slide again and again if you want to understand the concept very clearly. And if there would not have been any tilt in the earth then what would happen? Then the sun rays will fall perpendicular to equator throughout the year. And one more thing to know is that earth revolves around the sun in anti-clockwise direction. What is anti-clockwise direction? Anti-clockwise direction means west to east. Here the earth is revolving from this side. So now dealing with the basics of solstice. So shortening days and falling temperatures are marked the arrival of winter across the northern hemisphere as we have also discussed in our previous slides. So for people in north the year is the shortest, the 21st December day. The day of 21st December is the shortest and also the official beginning of the winter. And the reason for this solstice is that earth is tilted with respect to the sun at an average of 23.5 degrees. This means the northern and southern hemisphere receive unequal amount of sun lights over a year as we orbit our sun. So by the advent of winter solstice, by the advent of winter solstice, W.S. means winter solstice. So I repeat that by the advent of winter solstice in the northern hemisphere, the northern hemisphere cools down during this part of the year and it is tilted away from the sun. This is the most important thing to know that the earth is getting tilted away from the sun. And the winter solstice arrives at the time when the tilt is at its most extreme angle. So now we would be discussing that what is the relation of solstices with tropic of cancer and tropic of capricorn. So now we will be discussing that what is the logic of cancer and what is the logic of cancer. So now we will be discussing that what is the logic of cancer and capricorn with respect to this solstice. Just look at this diagram. If you would understand this diagram then your concept would become very clear. And no one can just defeat in this concept. Look at this diagram that this is sun. The sun is vertically overhead on two days each year. We have also discussed earlier on which days on March 21, March 21 and September 21. On these two days the sun is vertically overhead at the equator and these are called equinoxes. Meaning the duration of day and night would be equal on each and every place on the earth. And after March equinox the sun appeared to move northward this way. The sun appeared to move northwards. So by the northward movement of the sun the sun will be vertically overhead at the tropic of cancer. The sun would be vertically overhead at the tropic of cancer. This is vertically overhead. The sun is vertically overhead at the tropic of cancer on June 21st known as the summer solstice. So when the northern hemisphere will have its longest day and shortest night on the summer solstice. And by this the southern hemisphere will have shortest day and longest night. Similarly the sun would move further and there would be 21st September that is equinox. After that it would move further and on 21st December by December 22 the sun is overhead at the tropic of capricorn. And this marks the winter solstice when the southern hemisphere will have its longest day and shortest night. In this case the southern hemisphere will have longest day and shortest night. And this marks the beginning of winter in northern hemisphere. So taking the discussion ahead we can say that excess of the earth is inclined to the plane of earth's orbit. What is the plane of earth's orbit? The plane of earth's orbit is actually the plane in which earth orbits around the sun. That orbit that plane is tilted at 66.5 degree. And it is responsible to give rise to different seasons and varying lengths of day and night on the earth. And if this excess would have been perpendicular to this plane. All parts of the globe would have had equal days and equal nights at all the times of the year. And the sun is vertically overhead at the tropic of cancer on June 21. Due to which the northern hemisphere will have longest day and shortest night making the beginning of summer season. Northern hemisphere as we have also discussed this thing in the previous diagram. You can loop over that thing. Now look this figure. This figure is also similarly talked about that thing also. In this figure. This is sun. And on June 21. This is in June sources. The rays of sun is falling perpendicular to the tropic of cancer. And in December sources. The rays of sun is falling perpendicular to the tropic of Capricorn. So by December 21. The sun is overhead at the tropic of Capricorn. So look at this point here. The sun is overhead at the tropic of Capricorn. And this is the winter sources. When the northern hemisphere will have shortest day and longest night. You can remember it by SD and LN. Shortest day and longest night in northern hemisphere. Making the beginning of winters in the northern hemisphere. Okay. So this figure will make you more clear regarding sources. Specifically talking about winter sources. So as earth moves away from the sun. Okay. This is how earth is moving away from the sun. You can see this figure here. Okay. So on winter sources. The north pole. Would have six months of night. Okay. Because the southern part of the earth. Or the tilt of the earth. Moves towards the dark side of the sun. Dark side of the sun. It means that. The earth gets moved to. Moved away from the sun. Okay. And Arctic Circle. Would witness 24 hours of darkness. Similarly like the north poles. Tropic of cancer. Would witness. 13.5 hours of darkness. Means the duration of night is getting longer. Equator always. Have same duration of day and night. Everywhere. Okay. And Tropic of Capricorn. The night is also getting reduced. And Antarctic Circle. Would have six months of day. So. There are also some cultural significance of solstice. There are many cultures. There are many traditions. Which are related to these solstices. So for centuries. This day. This day of solstices. Had a special place in several communities. Due to its astronomical significance. And it is celebrated in many ways across the world. Okay. Jewish people. Jewish people. Jewish communities in which country. Israel. Okay. So. Jewish community. And Jewish people call the winter solstice. Which marks the start of winter. Similarly in Iran. And Afghanistan. Uzbekistan. Kazakhstan. Azerbaijan. Shabey Allah. Okay. And in the southern hemisphere. Where the winter solstice. Is in June. In southern hemisphere. The winter solstice falls in the June. In that condition. Peru celebrates the day with a festival called Inti Raimi. Inti Raimi means the sun festival. Okay. And in India. In Vedic tradition. The northern movement of the sun. The northern movement of the earth. On the celestial sphere. Which outlines the Uttarayan. What is Uttarayan? This is what we call in our culture. When the sun goes to Uttarayan. When the sun goes to Uttarayan. Then we need to do the full work. So that the sun can be found in the sun. In the winter solstice. Darkness falls. We connect it like this. So. Hence winter solstice is the first day of Uttaraya. Okay. So now coming back to our question. The question said. Consider the following statement with respect to solstices. First statement. Phenomena of solstices are associated with tropics. True this statement is correct. As it is. Summer solstice is associated with tropic of cancer. And winter solstice is associated with tropic of Capricorn. So this statement is true. This statement is saying. Winter solstice marks the longest day and shortest night in the northern hemisphere. Why is it wrong? Because this is the opposite. Winter solstice marks the shortest day and longest night in the northern hemisphere. So what is the correct answer? Correct answer is A. I hope that you understand each and every minute and big details related to solstice. With this. We will meet again with new topic. Till then. Keep learning. Keep growing and enjoy the life. Don't forget to like, share and subscribe to our channel. And press the bell icon to never miss an update.