Christian O. Feliciano Serrano: The light

As humans beings, we always have been curious about the mystery in the things that surround us, especially the daily events that can’t be explained that easily. Step by step as we expand our knowledge we learn that everything has a reason to be. It had happened that someone observes how something in the air is eventually attracted by the ground and realize that there is something that occurs every time, but what causes it? Or the situation in which a car is moving at a constant speed and stops when the driver wants to, but when we think about it in detail we realize the answer is more complex than just pressing the brakes. As those two examples, the world is full of common situations that have unusual explanations, wish makes the life of the curious exiting and more interesting. The majority of the people are conscious that the situations we study start to become an object of interest thanks to the observation of any particular aspect of something that caught the attention of our senses. Now, let’s focus on one of the senses, sight. Immediately after we open our eyes we are constantly receiving information from our surrounding, but what are the steps that are needed to be following in order to perceive the visual characteristics of an object as it is? What allows us to see the colors? What creates the colors or the rainbow itself? What allows us to see our reflection in a mirror or why the situation changes when it’s dark? All of those questions are part of our need to learn and they are all connected with one thing, the light.

But, what is the light? Using science of Physics as our tool we will try to solve many of our established unknowns. Properly speaking, the light is the radiation that spreads in form of waves in the empty space called electromagnetic wave. The color is related to the frequencies of the light in the spectrum called the visible spectrum with its wave lengths between 400nm to 750nm. More than 750nm and less than 400nm won’t be perceived by the human eye. Still, what is the light? In the beginning was well known that the light was pure and that the combination of the light with objects gives the colors, until scientific developed the prism. Through this tool scientists understood they were wrong about the white light. What we obtain from there, the white light is actually the combination of all the colors. Using the prism we can actually see the decomposition of the light in red, orange, yellow, green, blue, and violet. Another common example where it happens in nature is the rainbow. One drop of the rain works as well as a prism, spreading white light into the full spectrum. Each drop allows us to see just one color in the spectrum in our range of visibility. It is the combination of many drops reflecting one specific wave length which allows seeing the rainbow with all the colors in the spectrum. 

We now know what the light is, but how is it possible that we can see a particular color from an object? To answer this question we will return to the fact that the white light is formed by mixing all the colors. What occurs when the white light hits any surface is that when the light gets in contact with the surface all the colors are absorbed except the color that represents the color of the object itself. The colors that are not absorbed bounce away from the object. This action is what our eyes capture at the moment of seeing a color. We end up seen the color that wasn’t absorbed by the object. The colors that are absorbed have an energy that it’s never destroyed is transformed into other expression of energy such as heat. Another thing that creates curiosity is the fact that the light experiences changes in its direction each time it gets in contact with any surface. If the surface is smooth the incoming light ray will bounce resulting in a reflected ray, which has the same angle to the surface as the incoming ray, like it occurs when using a mirror. On the other hand, if the light ray gets in contact with a rough surface, the ray will reflect in many different directions which will cause the reflection to get diffuse as it occurs using a paper.

In conclusion, science, in our case Physics, can explain common events that have unusual explanations letting ourselves be guided by fundamental concepts. One of our most reliable senses, the sight depends not only in the capacity of our eyes; it depends in many physical aspects related with the light, what forms it and how it moves, things that we don’t usually think that happened. We use to think that the light is everywhere until it’s dark or that we instantly see it when we open our eye, but we don’t realize that just because the events are not easily captured by our senses, it does not mean they do not exist.

Steph Brunot: the theory of relativity

Einstein is considered the 20th century greatest scientist. He has given many contribution to many fields, but the theory that this paper focuses is on is the theory of relativity presented by Albert Einstein in 1905, and a fascinating time traveling theory. In general terms, the theory states that time is relative. In physics terms, the theory becomes a bit more complicated. There are three types of relativity:

1) Classical relativity

There is no object that is completely at rest or complete motion. This has to do mostly with the reference frame chosen by an individual. Even if you were to stand completely still, you would technically still be moving at a velocity of 40,320 km/h, which is the velocity of the earth.  If the earth were to come to a complete stop for 10 seconds, the human race would most likely go extinct due to the massive amount of carnage that would follow. Imagine, you are driving a car without a seatbelt and hit another car, you would without a doubt fly out of the car and hit the pavement, but the velocity of your short flight would the same as the velocity your car prior to the crash. 

2) Time dilation and space contraction

Einstein managed to find a way to slow down time. In order to better explain this, an example is needed. Imagine you were to have two mirrors in which a light beam was being reflected off both, and another set, of the same objects. Now one of the sets have begun to move near the speed of light, which is 299,792,458 m/s. The light beam of the moving set would actually travel a larger distance, but since the speed of light is constant, it would need a larger time to complete it, therefore making time, relative the other set that is at rest, slower. Although, Einstein observed that when objects moved faster their height would become contracted, therefore actually shortening the distance previously mentioned

Time has actually already slowed down in 2006 worldwide thanks to the three gorges dam built in china. It raised the sea level 175m above sea level which has the same effect of a figure skater that moves their hands away from their center in order to slow themselves down. The earth is actually moving 0.06 microseconds slower than it used to prior to the contraction of the dam.

Now to mention the theory stated before. Physicist compare space to a long sheet of paper. When a huge mass is place somewhere on the paper, all object dropped after will converge to that location. Such is the theory behind black holes; a star that has gotten so big, and it simply attracts everything that goes beyond its boundary, or event horizon as stated by Hawking. Now, let us assume that an object were to dropped inside of a black hole. It would be failing inside of it at a certain velocity that, conveniently, would be the 60 to 90 percent the speed of light. Inside of that black hole, our object would be traveling at a larger distance and therefore would take more time. Therefore that hypothesis states that black holes are actually capable of traveling to the future relative to our current concept of time. The next question in this problem, is how big the black hole actually needs to be. The mass of a black hole is directly proportional to its event horizon.

Sadly it’s only a hypothesis. Man will possibly be able of time travel but it will not be in the near future considering that we are still trying to populate other planets. It would most likely take billions and decades before we can even fathom the existence of black holes and its relationship to relativity.