By
Syed Ibrahim Rizvi
Scientists believe that an event occurred 13.8 billion years ago, which in their terminology is known as the ‘big bang’, that created the entire universe. Much later, around 4.5 billion yearsagok a small part of the Universe condensed in its far reaches and thus was created the solar system with the sun and the planets, including the Earth.
The formation of Earth and planets out of gases condensing into matter created an extraordinarily attractive force, which we now understand as gravity. The force of gravity became the force of attraction between the Sun and planets, and the planets started orbiting the Sun. Scientists explain that the revolution of the Earth and other planets around the Sun is due to the centripetal force.
Something else also happened when Earth was formed from matter that arose from the Big Bang. The spinning cloud of gas and matter created an angular momentum that made the Earth and the other planets rotate on their axis. The rotation of the Earth is absolutely important for its stability in its journey around the Sun in 365 days.
The rotation of the Earth is like a spinning top, which, when thrown from a string, keeps on spinning on a tip while maintaining its upright and stable position. As the speed of rotation slows down, the top begins to wobble and finally drops dead when the rotation stops. This is the status of our Earth. The Earth rotates at a speed of 460 meters per second, and this rotation keeps it stable on its axis.
The most important event that happens while the Earth rotates on its axis is that it creates day and night. Rotation makes circadian periods when the sun’s light falls on one side of the Earth and then the other side.
All living systems on this earth have evolved against the backdrop of this constant phenomenon of alternating day and night. Interestingly, the speed of rotation of our Earth has not been constant throughout the 4.5 billion years of its existence. As the analogy with the spinning top holds, the rotation of the Earth is also slowing down. In the past, the rotation of the Earth was much faster, and the days were around 6-7 hours. But the cosmic time scale is so huge that, fortunately, we do not experience the slowing of Earth’s rotation in the human historical time frame.
Humans have evolved experiencing and witnessing the sun rise every day from the east, the slow drift of the sun to its highest point, which marks noon, the slow descent of the sun towards the west, marking the afternoon, and the fading of the sunlight into darkness, which marks the start of night. This process for the last 4.5 billion years is being repeated again and again without fail. The constant regularity of this event is so ingrained in all life forms that have analytic ability that we, humans, invariably take everything for granted.
While the phases of the day are cemarcated by the availability of sunlight, there are periods which fall in between the phases of sunlight and darkness. The evening is the period when the day merges into night.
In the circadian calendar of humans, the time zone of evening has played a very important part. This is the time when humans have universally decided to break from the routine of the day. A labourer working on a construction site, a farmer ploughing a field, and a student studying for the examination invariably stop their activities when evening comes.
The evening, by its queer positioning in the time zone of the day, has built-in romanticism, which is hard to describe. The parks suddenly spring to life with children, and the roadside cafes become populated with the young seeking a cup of tea. Evening has invariably also attracted enthusiasts to kite flying. The joy of a kite tied to a string doing somersaults in the clear evening sky is indeed a delight.
The evening is also the time when Cupid plays his tricks on lovers. Poets have profusely used the evening as the time when lovers profess love to their beloved. Who can forget the song ‘ye shaam mastani, madhosh kiye jaye’ from the 1971 Rajesh Khanna and Asha Parekh starrer, Kati Patang.
The joy of evening continued to excite humans for most of their existence till about a couple of decades back. The advent of computers, social media, and intense human competition for available resources changed the timetable of the day that had existed for centuries. The evening was no more the time to relax, to go back home, or a time to delve into romance.
As humans sought more time for work, the evening suddenly vanished and merged into the night. The parks have been replaced by gyms, the roadside tea stalls where friends gossiped have been replaced by 5-inch screens of mobile phones where social media keeps teenagers glued to virtual acquaintances, and the romance of yore is now a relic of the past.
The death of the evening has also been aided by the fact that human activities are not dictated by available daylight. Humans now live 24 hours in artificial light. Scientists are now beginning to understand the bad effects of ‘artificial light at night’. A large body of scientific literature is now being generated that explores how exposure to blue light from mobile phones is playing havoc with human physiology by inhibiting the important hormone known as melatonin.
The loss of a perceptible evening time from our daily routine is perhaps a heavy price that humans are paying for technological advancement. Had there been no evening, we would not have had the adage ‘Subh-e-banaras, shaam-e-awadh’.
Poets are truly blessed that they sometimes see things much in advance. Or how else can one explain the thoughts of Gulzar sahab when he penned these beautiful but inherently sad lines: Ab toh din raat pe hi aake rukta hai. Mujhe yaad hai, pehle ek shaam bhi hua karti thi!”
The writer is a Professor of Biochemistry at the University of Allahabad