Why Does E=mc²? by Brian CoxThe most accessible, entertaining, and enlightening explanation of the best-known physics equation in the world, as rendered by two of today’s leading scientists.
Professor Brian Cox and Professor Jeff Forshaw go on a journey to the frontier of 21st century science to consider the real meaning behind the iconic sequence of symbols that make up Einstein’s most famous equation, E=mc2. Breaking down the symbols themselves, they pose a series of questions: What is energy? What is mass? What has the speed of light got to do with energy and mass? In answering these questions, they take us to the site of one of the largest scientific experiments ever conducted. Lying beneath the city of Geneva, straddling the Franco-Swiss boarder, is a 27 km particle accelerator, known as the Large Hadron Collider. Using this gigantic machine—which can recreate conditions in the early Universe fractions of a second after the Big Bang—Cox and Forshaw will describe the current theory behind the origin of mass.
Alongside questions of energy and mass, they will consider the third, and perhaps, most intriguing element of the equation: c - or the speed of light. Why is it that the speed of light is the exchange rate? Answering this question is at the heart of the investigation as the authors demonstrate how, in order to truly understand why E=mc2, we first must understand why we must move forward in time and not backwards and how objects in our 3-dimensional world actually move in 4-dimensional space-time. In other words, how the very fabric of our world is constructed. A collaboration between two of the youngest professors in the UK, Why Does E=mc2? promises to be one of the most exciting and accessible explanations of the theory of relativity in recent years.
What e=mc^2 Means
In physics , mass—energy equivalence states that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einstein 's famous formula: . Similarly, anything having energy exhibits a corresponding mass m given by its energy E divided by the speed of light squared c 2. Because the speed of light is a very large number in everyday units, the formula implies that even an everyday object at rest with a modest amount of mass has a very large amount of energy intrinsically. Chemical reactions , nuclear reactions , and other energy transformations may cause a system to lose some of its energy content and thus some corresponding mass , releasing it as the radiant energy of light or as thermal energy for example. A consequence of the mass—energy equivalence is that if a body is stationary, it still has some internal or intrinsic energy, called its rest energy , corresponding to its rest mass. When the body is in motion, its total energy is greater than its rest energy, and equivalently its total mass also called relativistic mass in this context is greater than its rest mass.
It's even the title of a Mariah Carey album. But what does Albert Einstein's famous equation really mean? For starters, the E stands for energy and the m stands for mass , a measurement of the quantity of matter. Energy and matter are interchangeable. If you've ever read Dr. Seuss's children's book "The Sneetches," you probably remember how the yellow, birdlike characters in the story go through a machine to change back and forth between "star-bellied sneetches" and "plain-bellied sneetches. It's the same way with energy and matter.
Let's play a game! The speed of light is just a number, right? Or ,, "miles" per "hour," whatever those are. What if, instead, we just said the speed of light was equal to…1. Just 1.