" For the rest of my life, I will reflect on what light is. " —Albert Einstein, ca1917
#Thousand_years_of_misconsecption
"What is light ? " - a simple question, thought it's answer till didn't get a full stop yet. The efforts of Human race to understand light and the process of our vision started almost 2500 years ago.
Greek mythology says, Aphrodite (Ἀφροδίτη) , daughter of Zeus and Dione, and the goddess of love, beauty and sexuality, sets fire in our eyes. And the fire from our eyes, fall on objects and thus we see see the world around us.
As per researches by the historians, it was #Empedocles(500 BC) who first proposed the "Fire Emission theory of Vision ". In his theory, he just followed the Greek mythology mentioned before. Later, we can see, another Greek philosopher and astronomer #Archytas (428-347 BC) presenting the same theory of vision.
About 300 BC, #Euclid in his book #Optica wrote that, light travels in straight lines. He also described the laws of reflection and also studied on the apparent sizes of objects and angles they subtend at the eye. But was still using the Emission theory in his works.
Next comes the era of Ptolemy (90-168 AD). He studied Euclid's works and side by side also measured the angle of refraction in water for different angles of incident and made a table of it. But the correction was far away. Yet, at 55 BC, Lucretius, a Roman atomist proposed that, the light and heat of the Sun are made of minute atoms. Thought, no one listened to him then.
#Āryabhatta (आर्यभट) and his #Suréyasedhanta
The Indian philosophers of that time also considered eye as the source of light. But, around 500y AD, Āryabhatta in his book on astronomy "Suréyasedhanta" mentioned that, not the eye but the source of light is the external objects like the Sun. Light from those sources fall on objects and reflected in our eyes, making the world visible to us.
#Kitab_al_Manazir(كتاب المناظر)/ #De_Aspectibus (965-1039 AD)
#Iban_al_Haytham of often called as #Alhazen is famous as #father_of_optics , born in Barsa, the then Mesopotamia (now Iraq) .His book contains first scientific works on basic optics along with study over pin whole camera and rectilinear propagation of light. This book was translated later by Friedrich Risner in 1572 with the title "Optica Thesaurus".
Kitab al Manazir was the first significant work on optics ever, based on actual properties of light. This book is preserved in parts in many places of the world. One of them is in #Bodleian library, #Oxford.
Thus we can see how we bared a great misconception for nearly about 1000 years. Yet lots to discover about light as it is fastest than anything of us . Who can say that a new theory arrive and make this old one we use wrong. So keep looking.