Earth Science: Physics and Technology – Physics – Optics
Up to a few years ago, optics were considered one of the areas of physics that promised few innovations: telescopes and lasers have been known for some time. All this changed with the arrival of photonics.
A Nobel Prize in 2005 in the area of optics, together with a predicted computer revolution, gave rise to great expectations.
Earth Science: Physics and Technology – Physics – Light
Without light, life on Earth as we know it would be impossible. The principal source of natural light on Earth is the sun. Yet physics deals not only with light visible to man, it also deals with electromagnetic radiation.
It is the energy of sunlight that makes our planet habitable. We value a well lit enviroment, and the basis of our nutrition is the ability of plants to produce organic substances from light, carbon dioxide, and water. Futhermore, we as humans require sunlight to produce vitamin D, a lack of which leads to liver, kidney, and bone disorders.
Sunlight is also essential for our mental balance: many people become depressed during winter or when deprived of light. For a long time, there were two competing answers to the question as to the nature of light. According to Isaac Newton (1643-1727), light consisted of tiny particles that move from the light source through space in a straight line.
On the other hand, Christiaan Huygens (1629-1695) described light as being wavelike. During the 19th century, this wave model seemed to persevere: for instance, Thomas Young (1773-1829) showed in 1803 that light could overlay and interfere, a phenomenon that occurs only with waves.
James C. Maxwell (1831- 1879) was even able to derive light waves from his electromagnetic basic equations. However, the turning point came at the beginning of the 20th century: atomic experiments proved that light is always given off in individual particles called photons. If such a photon encounters an electron, it behaves just like a particle with impulse and speed.
Both explanatory models were therefore shown to be correct. Thus quantum mechanics explains that light as well as matter have wave and particle characteristics. In many cases, one of the two characteristics outweighs the other, and sometimes both models have to be applied.
On the basis of this work, French physicist Louis de Broglie (1892-1987) developed an entirely new academic field called wave mechanics, which combined the studies of both light and matter.
GOETHE’S THEORY OF COLOR
Johann Wolfgang Goethe (1749-1832) was not only a poet, writer, thinker, and politician, he also had interests in history and natural sciences. In 1792 he published his Contributions to Optics and in 1810 his Theory of Colors.
Although in some ways flawed, his theories about color perception are still considered groundbreaking.