Light Science Summary 8. Missing a fresh morning Sun and a peaceful evening Sun.

 Earth was formed around 4.5 billion years ago and our solar system is one of more than 100 billion stars in our galaxy, and it is estimated there are over 100 billion galaxies in the universe. Since the first life on Earth appeared 3.7 billion to 4.3 billion years ago, all living things on the earth - single cells, plants, fish, algae, animals, and humans-are affected by the Sun and photon energy. They have adapted themselves and evolved with their circadian rhythm.

 The Nobel Prize of Physiology or Medicine 2017 was awarded to the three scientists who made critical contribution to understanding of the molecular mechanism of the circadian clock of fruit flies. The cyclic genes (Per protein) regulated under the light, which they have found, work as in the cells of unicellular and multicellular organisms. Especially, the biological clock influences the human’s behaviors, releases and keep hormone, maintain and control sleep, body temperature, and metabolism interacting with the main functions of the human body.

 The universe is made of atoms, and the atom is composed of a nucleus and one or more electrons around the nucleus. And, the light as the cluster of photons in the house is emitting 1018 photons per second. In fact, the short wavelength light classified below green’s wavelength, particularly, the blue photons, having high energy, used to have electron bounced off from its orbit of the electrons of atoms, and influence all the objects including the human being. The skin cells are regenerated in about every 10 days, however, the eye cells are not regenerated for their life at birth, so we should be careful of artificial bad light.

 The people are living under the artificial light with different spectrum than natural one during their most of time. The biorhythms’ balance is affected under such circumstance, the 24 hours sleep cycle used to be broken. And it can cause several disease such as sleep disorder, autoimmune diseases, obesity and diabetes, and a variety of psychological disorders including depression, mood swings, and seasonal emotional disorders.

It is also becoming clear that the light close to natural light has a profound effect on the health of plants and animals, which eventually the human beings are consuming. This is why in this era of artificial light flood, the lighting paradigm needs to be changed from simple artificial light to natural light. More desirably, it would be nice to be able to live indoor feeling from fresh morning Sun through noon sun to evening Sun.

Fig 8. The sun spectrums of morning, afternoon, and evening (Photo credit: Graph, Proc. Royal Soc. B.; Sunrise and Sunset,; The sun in the middle of the day,

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** Reference.
Gillette MU, Tischkau SA. (1999) Suprachiasmatic nucleus: the brain's circadian clock. Recent Prog. Horm. Res., 54:33-58; discussion 58-9.

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Graph, Proc. Royal Soc. B.; Sunrise and Sunset,;

The sun in the middle of the day,

Biologist A-Young Lee Ph.D
Biologist Jin-won Kim Ph.D
Biologist Jae-ho Lee Ph.D
Biologist Sang-wook Chung Ph.D
Physicist Sung-soo Kim Ph.D
Electronic and Information Engineering Sooyoung Moon Ph.D
Physics & MBA Chung H. Lee Adviser


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