Science in the Glorious Quran: Stillness at Night

• “فَالِقُ الْإِصْبَاحِ وَجَعَلَ اللَّيْلَ سَكَنًا وَالشَّمْسَ وَالْقَمَرَ حُسْبَانًا ۚ ذَٰلِكَ تَقْدِيرُ الْعَزِيزِ الْعَلِيمِ” (الأنعام:96).

“He splits the dawn and appoints the night as a time of stillness and the Sun and Moon as a means of reckoning.” (Qur’an, 6:96)

The night is the time for rest, not only for humans but also for other organisms. Many mammals, such as chimpanzees, gorillas, elephants and squirrels; birds (like sparrows and pigeons); reptiles (like lizards); and insects (like butterflies and honeybees) are active during the daytime and rest at night.

In humans and mammals, the hormone melatonin is secreted to prepare the body for sleep and the heartbeat and respiration rhythms slow down as the blood pressure falls. If humans fail to sleep, their immune system weakens and they become more susceptible to sickness. In addition, their concentration decreases and they may fail to think logically and even to hallucinate.

Plants also conserve energy for the daytime. The chloroplasts responsible for photosynthesis are highly dynamic at daytime and become still at night.  During the day, the chloroplasts move around in the plant cells to capture solar energy and convert it into stored energy molecules.

On the other hand, the pores of the stomata of the leaves of plants–which regulate the flow of gas and water vapor between the leaf and its environment–are closed at night. In addition, some plants fold up or drop down their leaves and close their flowers at night.

If we go down to the atomic level, we find that during daytime, the sun’s heat and radiation increase vibration and movement of the molecules of water, which, therefore, are faster during daytime compared to night.

However, it should be mentioned that God also refers to other organisms which are active at night, such as bats and owls, in the following verse:

“وَلَهُ مَا سَكَنَ فِي اللَّيْلِ وَالنَّهَارِ ۚ وَهُوَ السَّمِيعُ الْعَلِيمُ” (6:13).

“To Him belongs whatever rests in the night and the day. He is the Hearing, the Knowing.” (Qur’an, 6:13)

At night things become still and rest. Even molecules of water, in the absence of sun radiation and heat, are less energetic and are closer to one another (right).

Humans and many mammals, birds, and reptiles rest at night

At night, plants’ chloroplasts become still (left); stomatal pores close (middle, B), and leaflets of some plants’ leaves may fold (right, B).