The constancy of the speed of light has two consequences that make it possible, namely, length contraction & time dilation. According to Einstein, this makes no difference to you — you can’t even tell that you’re moving. Daniel Robbins received his PhD in physics from the University of Chicago and currently studies string theory and its implications at Texas A&M University. A non-inertial reference frame is simply an accelerating reference frame. The latter, General Theory, was proposed by Einstein in 1915. The most famous work of Einstein’s life also dates from 1905 (a busy year for him), when he applied the ideas of his relativity paper to come up with the equation E=mc2 that represents the relationship between mass (m) and energy (E). The object goes faster, but it also gets heavier. Lessons. the Earth’s revolution around the Sun. Einstein’s theory of special relativity created a fundamental link between space and time. A heavier object is harder to speed up, so it’s impossible to ever actually get the particle up to a speed of c. Until Einstein, the concepts of mass and energy were viewed as completely separate. Phenomena Explained by Special Relativity. The revolutionary physicist used his imagination rather than fancy math to come up with his most famous and elegant equation. In the latter part of the 19th century, physicists were searching for the mysterious thing called ether — the medium they believed existed for light waves to wave through. It can be best understood with this example: you are on a vehicle travelling at 10m/s, then you throw a ball forward at 10m/s. I understand and agree that registration on or use of this site constitutes agreement to its User Agreement and Privacy Policy. Don’t worry if what you have learned in high school physics is wrong, the formula for momentum reduces back to p = mv since the speeds that we normally use is much less than the speed of light. This is described in the twin paradox. The case point scenarios where special theory comes into play can be proven through Lorentz transformation. To make it easier to understand, think of it like this: being inside of a vehicle that is traveling at a constant velocity is the same as being inside a vehicle that is at rest (velocity = 0). You can picture this for yourself by understanding the thought experiment depicted in this figure. If you move fast enough through space, the observations that you make about space and time differ somewhat from the observations of other people, who are moving at different speeds. An outside observer will then see the ball to have a velocity of 20m/s. Special relativity includes only the special case (hence the name) where the motion is uniform. You may think that you are at rest, but the Earth is actually moving at an approximately constant velocity through space around the Sun. Moving at relativistic speeds can be seen as time travelling towards the future. The universe can be viewed as having three space dimensions — up/down, left/right, forward/backward — and one time dimension. The principle of the speed of light: The speed of light is the same for all observers, regardless of their motion relative to the light source. Learn. At speeds approaching that of light, the momentum increases. Imagine that you’re on a spaceship and holding a laser so it shoots a beam of light directly up, striking a mirror you’ve placed on the ceiling. In a nutshell, Einstein found that as an object approached the speed of light, c, the mass of the object increased. The point at which you are making your observation is where your reference frame is. (Top) You see a beam of light go up, bounce off the mirror, and come straight down. This formula would still be correct. 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