A Brief History of Relativity (Cont.)

Part 5 Einstein's Ideas

     As it was known throughout the 20th century, Einstein re-imagined and completely changed some of the most prominent scientific thought of his time. However, he was not done there with his theory of relativity and E=MC2, for once his gears started moving, so did the rest of the scientific world. There was one fault to Einstein's theory of relativity though, and that was even though the theory coincided with the laws of electricity and magnetism, it was not compatible with Newton's law of gravity. As stated in the book, it says that this law explains "that if one changed the distribution of matter in one region of space, the change in the gravitational field would be left instantaneously everywhere else in the universe." With this law, it essentially means that we could send signals faster (which is forbidden by the law of relativity) through out the universe. It also, meant that there had to be a required existence of universal time, which the theory of relativity also abolished. Once Einstein returned to Prague in 1911, this is when he seriously put some thought into deciding what he could do to solve the problem and this is what he deduced.

       There is an actual tight relationship between gravitational fields and acceleration, and so he came up with this example of a man within an elevator. He said to imagine someone inside a closed box, such as the elevator, the individual inside could not tell if that box or elevator in this case  was at rest due to Earth's gravitational field. Also, one could not even accelerate in that matter or free fall at an extreme distance within the elevator due to confinement. As a result of this conclusion Einstein, upon his return to Zurich in 1912, discovered that the there will be an equivalence with acceleration and gravitational fields only if the geometry of space time was curved and not flat.

 To put it in other words, for example, from the book, objects such as an apple or planet would try to move in a very straight and forward line through space time, but due to the gravitational fields, their paths would seem to appear to bent because space time itself is curved. Eventually after this study, Einstein collaborated with Marcel Grossman, to write a joint paper putting out the idea that what is known as a gravitational field to us, is simply a result to due the curvature of space time.

A Brief History of Relativity (Cont.)

Part 4 E=MC^2

As time progresses in Einstein's year, his theory of relativity starts reach some critical acclaim within the world of science which eventually gets him the Nobel Prize in 1921.With the establishment of Einstein's foot now firmly planted, he starts to express his ideas more rampant throughout the world. With the theory of relativity, their was one consequence of the relativity which is due to the relation of mass and energy. As a result, Einstein postulates an idea, or in this case an equation known as E=MC^2, which inevitable leaves its mark not only on the world of physics, but as the world as a whole. This equation explains that since the speed of light appears the same to everyone, then nothing within our known universe can move faster than the speed of light. To break this idea and equation even further down, is that when an object uses energy to accelerate any process, than the mass must increase as well, which in turn makes the object more difficult to accelerate. Now, to accelerate an object to the speed of light then, there must be an infinite amount of energy. What Einstein done with this equation is that it explains that mass and energy are equivalent, and all that is needed to be done is to square the speed of light. His equation showed a very important relationship with mass and energy which ultimately lead to one of the most dangerous weapons known to mankind. As a result of the discovery of nuclear fission, the atomic bomb was created through the Manhattan Project. This led to the creation of two bombs that would not only end World War II, but also completely obliterate the Japanese cities of Nagasaki and Hiroshima. Since Einstein was the man behind the discovery of the relationship between mass and energy, he was heavily blamed for the destruction.  However, as quoted from the book "that is like blaming Newton for causing airplanes to crash because he discovered gravity" and in all actuality, Einstein never participated with the Manhattan Project and he was utterly horrified by the droppings of the atomic bombs over the cites.

This video gives a brief description over the equation and really explains the concept well. Check it out!

A Brief History of Relativity(Cont.)

Part 3 Einstein's Revolution 

In June 1905, Einstein began his thirst for knowledge, which inevitably created one of the most influential and prominent works in the world of science. He started off with the thought that if someone could not distinguish whether or not the particular object or individual was moving through space, then the whole notion on the ether was redundant. Instead, he believed that the measure for the speed of light should be the same, no matter how fast these individuals or objects were moving. In other words, Einstein thought that every one or object had a personal set of time. Thus saying that the speed of light is completely independent from the individuals or objects motion. As a result of this, Einstein's ideas did not receive much attention because it would require the lost of an already well established theory.  However, Einstein's ideals were confirmed by a number of experiments, as for example, two accurate clocks were flown around the world in opposite directions. When the clocks finally returned to the point of origin, it was noticed that they had different times. This then lead to the idea of the twins paradox, in reference with the ideals of Einstein, in where the twin that leaves earth travels around space going at the speed of light. The other twin remains on Earth, and due to the motion of the Earth, will age more rapidly than the twin in space.  

Theories like this helped Einstein postulate that the laws of nature should be applicable to all freely moving observers. This lead to the establishment to one of his most prominent works, known as the theory of relativity and with the name, implied that only relative motion was imperative. As a result of this, Einstein completely done away with two of nineteenth-centuries major scientific notions of the ether and absolute or universal time would equally measure on all clocks.

A Brief History of Relativity(Cont.)

Part 2 The Fixed Ether Theory

Before Einstein gave a contribution into the theory behind time and space, scientist in the nineteenth century actually believed that they were just about to come to a final discovery that will completely describe how the universe came about. During that time, the belief was space was filled by a continuous medium known as the "ether" This ether was composed of radio and light rays and all that was needed to finish this theory was a precise measurement on the elasticity of it. However, once the century was coming to an end, some discrepancies started to appear. Behind this ether theory, or known as the "Fixed Ether Theory", it was assumed that light traveled at a fixed speed through it. The only other condition to this though was that if an object, for example, a spaceship, was traveling through this ether, in the same direction as the light, its speed would be lower while going in the opposite direction it will be higher. 

Unfortunately, for the scientist at the time, the experiments conducted failed to support the theory. Even the most accurate of studies conducted by Albert Michelson and Edward Morley came to a disappointing end once they discovered that the apparatus they developed did not show a difference in the speed or direction of light when put towards sunlight. Then some scientist, like George Fitzgerald and Hendrik Lorentz suggested that within the ether any body moving through it would be slower, but this still did not support the idea that the speed of light was overall the same. 

A Brief History of Relativity

 

The Author Stephen Hawking

The Universe In a Nutshell by Stephen Hawking begins with an explanation of two very important fundamental theories of the 20th century. First, being the theory of general relativity, and secondly being, quantum theory which were both laid out by Albert Einstein. Furthermore, the book eventually ties these theories together and explains how our universe's history is determined by a "tiny nut".

Book Cover

 Part 1 The Man Behind it All

The man behind these two theories including a plethora of more, was known as Albert Einstein, who was born in 1879, in Ulm, Germany. At a young age, Albert was no child prodigy, but he did averagely among his peers, even though there are some claims that he was incompetent in school. Albert also, had a distaste in authority which plagued him through out his youth. In the year 1900, he completed his education and graduated from the esteemed Federal Polytechnical School, known as ETH at the time. Unfortunately, that distaste in authority caught up with him and he was unable to claim an assistant's position at the school. Luckily for him, two years later he was able to get a junior post at the Swiss Patent Office, in Bern. Fast forward three years from then and it was at this job where Einstein established himself as one of the world's most prominent scientist, in where he began  a scientific revolution that completely altered our comprehension of space, time, and reality itself.