This theory was first introduced by Albert Einstein in the 1920. Essentially, it states that nothing is absolute. Position, speed, space, time, momentum, all are relative and vary between different observers and frames of reference. This was completely against newtonian laws, which stated everything was fixed and absolute so it had a very dramatic impact in the scientificcommunity.
It divides into two branches, Special relativity and General relativity. Special relativity teaches us that the speed of light is always constant, regardless of the speed of its source or that of the observer. That means that it doesn’t matter if the observer is moving towards or away from a star, or if the star is moving towards or away from the observer, the light the starirradiates will always pass the observer at the speed of light. Another important thing to know is the light is the fastest thing in the universe, nothing can surpass it. Special relativity is applied in situations where motion is inertial, where the object isn’t actually accelerating.
The same effects in Special relativity apply to General relativity, the only difference is that general relativitycovers a more vast and complex zone of study, and includes every single frame of motion that is non-inertial. It introduces even more principles, such as the faster an object moves, the more massive it becomes. The faster an object moves, the slower time ticks (Time dilation). When moving at high speeds, objects becomes shorter in length, so distances appear to stretch. To cover everything aboutrelativity would take volumes, so I will explain a bit about time dilation to show how complex this stuff can be. The faster an object moves, the slower is the time it experiences, but the differences become more dramatic near or at the speed of light. The means a moving clock would tick slower than one that is stationary. If two persons hold clocks perfectly calibrated to be ticking at the sametime, and one of them remains stationary while the other one drives to the next city and then drives back, the clock of the moving person would actually be earlier than the one that remained stationary, but a car moves so slowly compared to light than the difference is literally unnoticeable. If the same idea is repeated, but this time the moving person takes a rocket and travels to outer space atthe speed of light, leaves the solar system, and then come back, his clock would be years earlier than the one the remained stationary in Earth. Actually, if both persons were twins of the same age the one that left would still be pretty young while the one that remained on Earth would be old due to the time dilation occurred because of the fast speed and other factors encountered in spacetimeduring the trip. Of course, this is impossible to experience since nothing can go as fast as the speed of light, and even if a human could achieve such speed, the insane speed would make him gain so much mass he would be crashed under his own weigh (He would alone, even more assuming he is using a machine). Relativity remains one of the most complex areas in physics today and very few are the peoplewho can understand it clearly.
Atoms are the basic structures of matter. They are all built the same way, with electrons, protons, and neutrons but they individualize from each other because depending on the weights, organization, and number of electrons, protons and neutrons is the type of atom. To understand how atoms move the whole universe, think from big to small. Theuniverse is made from galaxies, galaxies from planetary systems and stars, then planets, then biospheres, then ecosystems, the populations, then organisms, then systems of organs, then organs, then tissues, then cells, then cell organelles, then macromolecules, then molecules, then elements, and finally then atoms. During the 1920, studies concerning atoms took place and many advancements were...