Happy Winter

 Happy Winter 

We went through a perihelion phase this week (2-4 January) when the distance from the Earth to the Sun was the smallest (143.7 mkm). But we in northern hemisphere felt the cold wave. Why? Because our earth in inclined on its axis and is rotating. These days the South Pole is tilted towards the Sun, as a result the rays of Sun are not coming directly to us in northern hemisphere but are slanted, travels a longer distance and hear a larger area. Thus they have less heating power. 

The Sun radiates heat of which earth receives one part of the 2 billion parts. Out of 100% solar energy only 51% reaches the earth, 35% reflected back into space and 14% is absorbed by the atmosphere during insolation. The atmosphere additionally receives 34 units of earth radiation and making it 48%. If the inflow of the heat is less from the Sun, the heat quantity in the atmosphere also comes down in northern hemisphere, and therefore, the atmosphere around us is cold these days though the earth is nearest to the Sun. 

Winter is tough for the old aged people because the atmospheric pressure goes up. Those who have weak heart lungs couldn’t tolerate the pressure of the atmosphere and therefore die more in winter. The air with water vapour in summer and monsoon is lighter because the molecular weight of water (18g/mol) is less than the average molecular weight of air (about 29g/mol). Humid air is less dense, weighs less and exerts less pressure than the dry air. 

After 4th January the distance between the Earth and the Sun will go on rising till it reaches to the greatest (152.1 mkm), the aphelion occurs on 3-6 July, the North Pole will be tilted towards the Sun, will have direct rays of the Sun in northern hemisphere and will have a tough summer heat to face but with low pressure of the atmosphere. We need it, for the rainy season, otherwise how could we survive without water and food? 

Enjoy the play of the nature through the seasons. Season’s greetings. Happy Winter. 🥶 ❄️ 

Punamchand 

6th January 2024