To be able to see we are in need of two blessings granted to us: the eye and light. We aren't the only creatures who thrive on light; plants are also in need of light to perform photosynthesis. Unfortunately, we sometimes take these blessings for granted. The fact that we have discovered how the eye works most of the time makes us underestimate this miraculous organ. And light, which we constantly use, is also a victim of our familiarity with it.
In our times, the Big Bang Theory is generally accepted to be the starting point of the universe. When the Big Bang happened, the universe and light were simultaneously created. The universe came into being at elevated temperatures from a single particle.
For the events that happened after the Big Bang, the most recent and accepted theory is the Inflation Theory. According to this theory, right after the Big Bang, the universe started inflating at an incredible rate, quantum fluctuations were scattered throughout the universe, and a homogenous inflation happened which allowed galaxies to be formed. Light was created at this period for the very first time.
Ibn Sina was the first scientist stating is was possible to measure the speed of light. And Newton used the marble example to explain the phenomenon of light containing colors of different wavelengths. Modern theories state that light is composed of weightless and charge-less particles called photons. Light is now known to be electromagnetic waves that carry energy as well as having the characteristics of refraction and reflection. A major discovery occurred in 1975, when the Danish scientist Ole Romer was observing the satellites of Jupiter. During this study, he was able to prove that the particle model proved to be insufficient, as was seen from the diffraction of light (changing its direction after having passed a narrow slit)..
Although the wave model is more dominantly talked about in modern times, it is known that both models are true.
Various experiments have been done to understand the properties of light. One of these experiments was a photography technique applied by Dr. Edgerton, in 1964. In this photo, the image of the apple right after the bullet passed through it was captured. This famous photograph, which was captured in a millionth of a second, inspired Prof. Ramesh Raskar from MIT (USA) to take a photo of light in order to see it by naked eye. Raskar developed a camera that can take up to a trillion frames per second. This would make it possible to visualize the human body without using X-ray. The wave like property of light was studied by this new technology called Femto Photography.
Light is the fastest substance in the universe. As long as it does not change its environment, the movement of light is linear because of its electromagnetic wave properties. If it passes to a different but transparent environment, it continues its movement. If it passes to an environment where the refractive index is larger than its original environment, it comes closer to the line accepted to be vertical to the surface (normal) and vice versa.
The speed of light and all electromagnetic waves in an empty, airless environment is 299,792,458 m/s (300 thousands kilometers). With this incredible speed, the Earth could be toured 7 times a second. The letter c represents this speed in science, and it's based on the Latin name for speed: celeritas. While passing through any object (air, water, glass etc.) the speed of light is smaller than c.
If a laser pointer is activated for a thousandth of a second (a couple of femto seconds), a photon cluster is formed which is approximately 1 mm in width. This cluster of photons has a speed millions of times greater than the bullet passing through the apple.
What if the femto photo of a cluster of photons that were sent from the bottom of a glass bottle full of water was taken? How would the light appear in slow motion? Although this short journey of light takes place in less than a nano-second, it is possible to capture how it moves in slow motion by reducing the speed ten billion times with the femto camera. With this femto camera, it is possible to measure the average speed of light in a tomato and gain knowledge about its interior texture and quality without touching it. When a bunch of photons are sent to the surface of a sample, a three dimensional picture of it can be constructed by the high resolution detection of the photons that are reflected at different times from the sample.
With the science of light, technology for transportation that does not require a driver can be developed, creatures can be saved from natural disasters by the reflection of light on windows, and many new age surgery technologies can be developed.
In order for the eye to see, light needs to exist. One of the latest and most astonishing pieces of research done about light is the femto photography technology. By this technology, it will be possible to visualize the human body without the use of X-ray. If there was a femto camera incorporated in our cell phones, we would be able to understand the quality of the tomatoes we were buying when we went to the grocery store without having to touch them. By harnessing the great gift of light, we can make the great gift of life even better.