Who is Albert Einstein

Answer 1

Albert Einstein was a 20th Century Physicist who revolutionized the laws of physics and the way we think of the Universe.

Special Relativity

At the turn of the 19th century, working in a Swiss Patent office and fascinated with time, he published in 1905 his seminal work entitled “On the Electrodynamics of Moving Bodies” or more colloquially the “Special Theory of Relativity“, his thesis on the laws of motion governing bodies that are traveling at a significant fraction of the speed of light in an inertial or non-accelerating frame of reference.

The singular foundation of this theory, one that derives from Einstein’s fascination with time, is the invariance of the speed of light. Einstein tackled the seeming contradiction that, as a physical object approaches the speed of light, the relative velocities of light -and the object- don’t add; that is, the measured velocity of light, if its source is located in the frame of reference of the object, is the same as if the object was stationary, in other words, the speed of light is invariant.

Einstein theorized, quite correctly, that the solution to this seeming logical conundrum is quite simply that time slows down for the frame of reference of the object as that object approaches the speed of light. Since velocity is the change in position with time, time has to be the parameter in this equation that changes. Other physical aspects of the moving object change relative to the observer in accordance with the change in time, such as its mass and physical dimension along the direction of motion. These changes are known as the “Lorentz Transformations“, named in honor of the Dutch Physicist and Mathematician Hendrik Lorentz who first derived them as a group in 3 dimensions and which Einstein subsequently incorporated as a fundamental aspect of his Special Theory.

General Relativity

Newton was quite satisfied with what he provided as an explanation for the behavior of moving objects, not the least of which objects that were moving under the influence of gravity. The paradigm change between Newton’s ideas and Einstein’s, in short, was that Newton accurately described how objects moved while Einstein, in addition to how they moved, described why they moved as they did. In Newton’s “Clockwork Universe“, everything moved according to a fixed set of laws, his 3 laws of motion and his Universal Law of Gravitation. Given enough time, according to Newton, every outcome, ever, could be explained, deduced or, one could argue, predicted; the Universe was fixed, is set in motion and could be reduced to a combination of all that is contained in Principia. As a side note, this thinking, as with Relativity, both Special and General, is completely incompatible with modern Quantum Theory where outcomes are measured and evaluated based on probabilities and very little is known with certainty.

In Newton’s universe, gravity was simply a mutually attractive force, in the simplest case, between two objects, whose magnitude is the product of their masses and the inverse square of the distance separating them. Newton’s gravity law accurately described the motion of objects under the influence of this mysterious force, so much so, that it is used today to compute and predict orbits, trajectories and every aspect of an object’s motion or the integrated motion of a system of objects. Because Newton’s Law of Gravity only describes the behavior of an object under the influence of gravity and not the underlying cause, there are limitations to his law, a notable exception and one known to him, is a peculiarity with the orbit of Mercury and one only -and accurately- described by Einstein’s General Theory of Relativity.

As to the “Why” of gravity, Einstein’s GTR predicts that any object will mutually follow the “curvature of space” produced by each object with a magnitude proportional to each of their masses. This revolutionary idea would not have been possible during Newton’s time and the prevailing provincial attitudes of the day.

The Photoelectric Effect

Einstein was awarded the 1921 Nobel Prize in Physics for "his discovery of the law of the photoelectric effect", where he demonstrated the quantum nature of light and, by extension, the nature of matter. By exposing various substrates and materials to electromagnetic radiation (light, UV, IR, X-Rays, etc) of various energies/wavelengths, he was able to induce the flow of electrons and thus prove that the atom could be described as having a quantum nature that reacted to a specific energy, not a random energy. This theory would give rise to technologies we use today such as solar photovoltaic cells (Solar Panels).