The Summer Solstice Day
A solstice occurs twice a year, one is summer solistice and another is winter solstice.However, these can be ambiguous since seasons of the northern hemisphere and southern hemisphere are opposites, and the summer solstice of one hemisphere is the winter solstice of the other.
Whenever Earth's axis tilts the most toward or away from the Sun, causing the Sun to be farthest north or south at noon. The name is derived from Latin sol (sun) and sistere (to stand still), because at the solstice, the Sun stands still in declination, that is, its movement north or south is minimal. The term solstice can also be used in a wider sense as the date (day) that such a passage happens.
On or around June 21 each year, the rays of the sun will be perpendicular to the Tropic of Cancer at 23°30' North latitude. This day is the summer solstice in the Northern Hemisphere. It is the longest day of the year in the northern hemisphere. The reason is because the tilt of the earth's axis and the position of the earth relative to the sun make it so June 21 is the date when sun covers the biggest portion of the northern hemisphere at one time. If we were in the southern hemisphere, today would the shortest day of the year.
21st of June is the largest day of the year. It is the longest one because the amount of time from sunrise to sunset is longer than any other day in the year. In the sky of Bangladesh sun stayed for 13 hrs. & 36 mins.
Anushandhitshu Chokro, a leading science organization of Bangladesh observed the day in a unique way. Though the day is being observed in all over the world but in Bangladesh it is celebrated for the first time as mentioned in a press release. A day long program was organized at Biswa Shahitto Kendra. From 3 to 8 PM an exhibition was held where many people gathered to see the exhibits. Through a telescope people observed sun spot and night sky. People of different ages stood in a queue and enjoyed the views of the sky one by one.
Professor Abdullah Abu Sayeed gave his valuable speech and then Dr. Dipen Bhattacharya explained the history and the significance of the day. Shahjahan Mridha Benu Ex-General secretary of Anushandhitsu Chokro and President of Astronomy dept. of this organization discussed the difference of science and astronomy. Astronomer Dr. A.R.Khan also gave his valuable speech in this discussion program.
Two attractive documentary videos were also shown in the program. One was by Ronald Halder about the stunning natural beauty of two sal bans and The sundarbans of Bangladesh. Another documentary was presented by a young astronomer Naimul Islam Apu. It was about the collection of meteorite (ulkapindo) that fell in Thakurgaon in 2006. It was collected by the science organization, Anushandhitshu Chokro. The documentary was all about the experience and interesting things that happened there.
(Writer is student of Dept. of AIS, DU)