What is Relativity?

How did Einstein Influence and widely employ the thought of Relativity in laws of Gravitation and Spacetime?

During the early 20th Century, many people used concepts such as dark matter, string theory, religion and others to understand and grasp the theory of how natural components in our universe affect the law of gravitation. It was easily the most difficult scientific quest, with some physicists even deeming it impossible. However it wasn’t until a theoretical physicist extraordinaire, who had fled from the disturbed, preyed soil of Germany and the fatal grasp of death, had fully revitalized science in astronomical and theoretical studies, changed our thought process of space, time, light, travel and gravity forever and captivated masses from his fascinating and thoughtful vagaries of observation. His countless bold and mindful theories he developed during his years as a nobel-winning, mouth dropping, eyebrow raising and highly accomplished theoretical physicist proves why he is known as the greatest scientist to ever live.

However before the publishing of his 4th scientific research paper, Albert Einstein was widely discredited. Throughout his life, Einstein’s work always reflected disruption of social certainties and moral absolutes in the atmosphere of the early 20th Century. Although, it was clearly evident that Einstein was not just a basic, traditionalist scientist who would normally believe that previous experiments and theories would affect people’s thoughts. His nonconformist personality, his curiosity, his passion and his rebellious instincts all employed that Einstein wasn’t just a regular academia, and was actually a genius blessed with imagination and creativity. For example, Einstein’s first startling discovery occured whilst he was writing his fourth paper, in 1905. In that paper, he had completely removed Sir Isaac Newton’s concepts of absolute space and time, and then had applied it to an already derivative belief of electrodynamics of moving bodies. (Modified creation of absolute Space and time); doing this would introduce a new infamous and spectacular notion known as “The Theory of Special Relativity.”

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Albert Einstein

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Sir Isaac Newton’s concept of absolute space and time. (Einstein discarded this for the discovery of special relativity). This provided a theoretical foundation for all Newtonian mechanics. It is an idea, in science, about the properties of the universe. In physics, this idea of absolute space and time may be perceived as an identifiably and unique, hypothetical frame of reference, in which the basic laws of physics might appear as different when compared to other hypothetical frames.

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For example, this particular frame was used in Newton’s mechanics in laws of motion. It is an inertial frame; a frame of inertial reference, in classical physics and special relativity, is a frame that does not undergo any acceleration of motion. An inertial frame is either at rest or moves at a constant speed, although both states always have a linear motion.

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Here is a non-inertial frame. This frame of reference, travels in a rectilinear fashion as well but also accelerates and rotates around a certain axis. On the left there is no A (Acceleration), and on the right there is. There is also a blue line on the right that represents the rotational speed/movement around the axis, which is the black point. 

For instance, we evidently know from movements of pendulums and the axis alignment of the north pole’ star Polaris, that the earth performs a circular motion around its axis (the sun). Therefore, it is clear that our planet must have acceleration and a rotational movement so that it can move around circularly, this means that our planet is in a non-inertial frame of reference since it accelerates and also is able to rotate around a designated axis.

Ultimately, this is the concept of Isaac Newton that Albert Einstein had entirely discarded to discover special relativity. This now leads us on to understanding what special relativity really is…

 

The Theory of Special Relativity: Special Relativity is a concept in which it declares the basic laws of physics are the same whatever your motion may be. This concept that Einstein conducted, during his years living in Bern, Switzerland, applies only to a particular context. For example, if we were in a situation where observers are moving at a constant velocity respective to one another, whilst moving at a linear line in a steady constant speed: this is called an inertial reference system. Hence, this frame of reference explains how space and time are linked when objects move at a consistent speed (not acceleration) in a straight line. Ultimately, this had Einstein prove that the laws of physics are the same for non accelerating observers in an inertial reference frame as well; the speed of light in a vacuum (an area with no particles nor density) is the same no matter the speed at which another variable travels. These theories are applied in scientific concepts as long as gravitation is not unclassified at all. This would later be discovered as a problem.

 

After this theory Einstein had published as his fourth scientific paper, he later made a short addendum to it concerning the correlation between energy and mass; this formed his most famous equation and possibly the most famous equation of all time: E=mc^2.

 

However, after the publication of his fourth paper on special relativity, Einstein realised that it was incomplete. One way was that his concept only applied to a consistent-velocity motion and not acceleration, (only in an inertial frame of reference). In addition, his theory stated that no physical interaction can grow as much as the speed of light (referring to space and time), yet the notion was completely in denial with Newton’s discovery of gravity since it wasn’t factored in his theory at all.

 

Approximately a decade later (1915), Albert Einstein had then introduced General Relativity. Even though this notion sounds very similar to his previous discovery of special relativity, it is completely different. This now leads us on to understanding what general relativity really is…

 

The Theory of General Relativity: After Special Relativity came General relativity; it was founded during 1907-1915 and was published as a scientific paper as well as a science yearbook. When Einstein was studying how special relativity could have been fixed, he noticed two foundations; gravitational mass (weight on a field with gravity) and inertial mass (force required to push/move). Even though these were the same, these two theories were different in explaining one phenomenon. Thus, Einstein attempted to link two of these concepts together to create a more simple and united explanation. This led Einstein to realize a principle called “the principle of equivalence”; this principle explained that the effects of acceleration and gravity were equivalent. Einstein, with this observation in mind, came up with an eccentric idea that regarded space and time to actually be a fabric that curved (creating gravity). This had then emerged as a scientific breakthrough because of how gravity could be applied in 3 dimensional space and 4 dimensional space. 

 

This developed concept agrees with Einstein’s mistakes from his initial discovery of special relativity, because the acceleration of the natural factors (mass, light etc.) and the rotation of the earth means that this can also be applied to a non-inertial frame of reference; and it resolved the problem of gravity not being implemented before.

Evidently, Albert Einstein had to overcome a lot of challenges throughout his work life and his social life. He had to protect himself from war in his country, he had to overcome the beliefs and unsupportive behaviour from fellow colleagues, and most importantly had to survive as a refugee whilst working hard on a very demanding and high-level profession. Therefore, if you ever feel like something is too difficult or impossible in life, remember that … 

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Space and Time warping; perceived as Gravity.

“In the middle of difficulty lies opportunity”- Albert Einstein.

Albert Einstein

By Aayush Jalan 

(Year 9 Student at Bangkok Patana School)