It has vexed many scientists – even some of the greatest minds of 19th-century science – for many decades.
He correctly surmised that white light is dispersed into its component colors by gas molecules in the atmosphere and that blue wavelengths tend to be scattered less intensely than other wavelengths.
John Tyndall
John Tyndall was an Irish scientist specializing in light who first explained why the sky appears blue. According to him, sunlight from the sun passes through our atmosphere before reaching earth where its rays are scattered by air molecules (primarily nitrogen and oxygen atoms ) and dust particles, giving rise to its blueish tint. Additionally, scattering causes light refraction which gives an overall bluish hue to our view of things.
Tyndall was born in Leighlinbridge, County Carlow in 1820. He attended both the Royal Irish Academy in Dublin and Germany for his education, working first as a surveyor and mathematics teacher before making a career change to scientific work. In 1854 he assisted Michael Faraday with his experiments on magnetism before becoming professor of natural philosophy at London’s Royal Institution in 1854 – eventually joining its “X Club” and devoting time promoting science to non-scientific audiences via public lectures written for widespread distribution as well as contributing to its British Association committee committee on teaching of science committee.
Tyndall was one of the leading scientists of his day, known for his groundbreaking research into light. Additionally, he was an active mountaineer and glaciologist as well as co-founding the scientific journal Nature as well as creating the X Club, an association of scientists who promoted evolution as real.
Tyndall became fascinated with light’s interaction with gases during his later years. He conducted extensive studies of radiation’s effect on water vapor and carbon dioxide concentrations in our atmosphere and determined that any change to them would alter climate on Earth. While not the first to make such connections, his work provided crucial insight into understanding their roles within our atmosphere.
Tyndall passed away just on the verge of making breakthrough discoveries such as quantum theory and relativity – possibly accounting for his relative anonymity today. Louisa took possession of his papers, assigning herself supervisor of an official biography; unfortunately she procrastinated and never completed it. A more informal yet still useful book detailing his life and work was published by A. S. Eve and C. H. Creasey’s Macmillan and Company in 1945.
Lord Rayleigh
Lord Rayleigh first proposed an explanation for why the sky appears blue over two hundred years after its discovery. To this day, his theory remains one of the best explanations as to why it appears this way.
Rayleigh first proposed his theory of scattering in 1871, asserting that when light passes through a gas it encounters particles which scatter or bend it in turn, producing scattering or bending effects proportional to wavelength (small particles such as those present in air). As such, blue light is scattered more than red light causing its brightness to appear bluer, thus giving us blue skies.
Before, Tyndall had suggested that the blue color of the sky is caused by dust and droplets of water vapour; but Rayleigh disagreed and understood that gas molecules scattering light was likely responsible. Furthermore, Rayleigh realized that when setting behind clouds the shadow cast by these clouds can look blue due to more blue light being scattered than any other colors.
As soon as he took on his father’s title of Baron Rayleigh, Rayleigh made a strategic decision: He resigned his Cambridge chair and returned home, as his financial situation had greatly improved and this would enable him to focus solely on scientific research without worrying about university obligations.
Rayleigh conducted extensive experiments using gases like coal gas, carbon dioxide and water vapour as strong absorbers of radiant heat emitted by the Sun. These studies are crucial as its warmth sustains life on our planet.
Rayleigh’s work is highly esteemed, and many physics laws, constants and even craters on Mars and the moon bear his name in recognition. But perhaps his most celebrated contribution was his 1907-1911 theory of critical opalescence that eventually resulted in an equation bearing his name, helping establish statistical physics as a field.
Sir Isaac Newton
Sir Isaac Newton is one of the greatest scientists of his era, having created a theory of gravity and discovering laws of motion (which became the basis for modern physics), as well as inventing calculus and an innovative telescope type. Additionally, Newton was among the first people to demonstrate that white light consists of various hues.
The sky is blue because sunlight that passes through it is scattered by tiny particles in the atmosphere that contain molecules of all colors of the rainbow, including blue and violet wavelengths, which cause light rays to scatter more intensely than other wavelengths, giving rise to its signature hue.
Lord Rayleigh devised a mathematical equation in 1871 that detailed this phenomenon, showing how its intensity is dependent upon the fourth power of wavelength for very small particles like those present in air. Blue light scatters more readily than red, explaining why our skies are bluer.
Though Newton never fully understood this theory, he took it as given and went on to explore other phenomena in his own distinctive manner. His focus was predominantly mathematical and he produced key theories such as gravity’s force and laws of motion – as well as developing the first reflecting telescope.
Newton was revered as one of the foremost scientists of his era; however, his life was often marred by controversy. He and his mother engaged in a longstanding feud and in 1678 suffered what may have been an emotional breakdown due to his dispute with other scientists over colour theory.
Later in his life, Lucasian Professor continued making discoveries while also serving as a government official and writing about infinite series. Nonetheless, in later years his interest waned considerably – though he did write a tract about them! His life can be divided into three periods; those leading up to him being appointed Lucasian Professor; these years as an official; and finally the period leading up to his ill health and eventual decline which eventually resulted in his death in 1727.
Louis Pasteur
As we gaze out on a clear day, it can be easy to take for granted the color of the sky. But there’s actually an explanation as to why it is blue; its source lies within our atmosphere’s physical makeup and light passing through. When sunlight penetrates air molecules and passes into space, its light is scattered all directions by molecules within. Rayleigh scattering occurs where molecules scatter light at either end of its spectrum more strongly – blue end rays are most strongly scattered as a result of Rayleigh scattering.
Physical scientists generally credit John Tyndall with discovering this phenomenon, although Lord Rayleigh later refined it further. Rayleigh realized that scattering intensity is directly proportional to wavelength in small particles like air. Thus blue light will be scattered more than red; hence creating what has since become known as the Tyndall effect and playing an essential part in our understanding of our Universe.
Louis Pasteur was born in Dole, a small town in eastern France. As a child, Pasteur displayed little aptitude for art but showed great scientific ability. At age 12, he began studying crystals; carefully dissecting two acids into their individual crystals until discovering mirror images – evidence of chirality. Through these studies he earned both an arts and science degree at College Royal de Besancon (1842) before attending Paris’ Ecole Normale Superieure to study chemistry before eventually receiving his doctoral degree (1847).
After graduating, he began work on multiple scientific projects, particularly fermentation and bacteriology. His expertise earned him the title “Father of Bacteriology”, leading him to create methods used in vaccine manufacturing as well as lifesaving drugs like HIV vaccine. In addition to founding journals Physiologie des Serums and Society of Bacteriologists; he was a member of France’s Academy of Sciences as well as receiving multiple distinctions including France’s highest award, Legion of Honor.