Friday, May 20, 2022

E = mc²

 From Delancey Place:

E = mc²

Today's selection -- from Frequently Asked Questions about the Universe by Jorge Cham & Daniel Whiteson. 
 Einstein teaches us that mass and energy are different forms of the same thing:

"If there's one physics equation most people know, it's probably E  = mc2. It's the most famous equation in physics, likely because it's easy to remember. Its form is simple and elegant, almost like the Nike 'swoosh' logo. Compared to other physics formulas that look more like Egyptian hieroglyphics, this one definitely has brand appeal. Of course, it doesn't hurt that it came from Einstein, whose brilliance (and famous hairdo) have been a part of popular culture since the last century.

"But physics formulas are not just math; they're supposed to de­scribe something about the physical universe. And this is another reason why E = mc2 sticks in people's minds. Here E stands for energy, m means mass, and c is the speed of light in a vacuum, or 299,792,458 meters per second. To have them all in a simple, easy­-to-remember formula implies that they're connected to one another in a deep and profound way.

"But what exactly does that mean? How are mass and energy and light actually related to one another? And what does this relationship say about the fundamental nature of ourselves and the universe?

"For most of us, mass is the stuff we're made out of. If something has mass, it generally means that it's heavy, hefty, substantial. We tend to think of things with less mass as lighter, ethereal, or barely there.

The equation in Albert Einstein's own handwriting from 1912

....MUCH MORE