can anyone explain this popular equation?

Question

E= mc squared

Answer 1

A lot of answers, and most of them good.

Let me try and clarify a few things.

This is a hallmark of special relativity, not general, although the distinction between the two is blurred somewhat in this context. I'd probably say the defining equation of general relativity is the Einstein equation which relates spacetime curvature to energy and mass density.

It's also incomplete as stated in popular context. The full equation is (in whichever units you wanna make it):

E^2/c^2 = p^2 + (mc)^2

Only if the momentum (velocity) is small compared to the rest energy (mc^2) does this equation get to where you want it to be.

Now, the physics of the matter is not:
1. This is how much energy is in mass. This implies that the two are interchangeable and this simply isn't true. Photons have energy, but they don't have mass, and you can't convert it to have mass.

2. It's not the energy that a particle has whenever it moves whether or not its at the speed of light (an impossiblity for a massive particle anyway!).

What it is:

This just says that there are additional considerations when you consider the relativistic properties of a massive particle. The available energy to the particle does not only come from kinetic (velocity) considerations, but also the bonding between the constituent particles.

Look at this equation more as the consequence of being massive, rather than some sort of energy/mass conversion routine. Now, don't get me wrong, mass does turn into energy (e-e+ collisions) but energy doesn't turn into mass, if the "rest mass" increases, it's because you've increased a bonding somewhere (ie added a "massless" spring between two objects). It's contrived, but it gets the point across. You've bonded two objects together, and the "rest mass" is now greater than the combined "rest mass" of the two individual objects, but this is accounted for in the energy in the bond between the two.

It's a sticky situation that's oftentimes overexaggerated for the sake of simplicity. Sorry if I stepped on some toes here.

Answer 2

Energy is equal to the product of mass and the speed of light squared

Answer 3

Einstein came up with this equation where:
energy is (E), , and mass is (m). In this formula, c², the square of the speed of light (in a vacuum), is the conversion factor required to convert from units of mass to units of energy, the energy per unit mass.

Answer 4

as the others said. Energy equals Mass times the speed of light Squared.

what does it mean???

it means if you take a kg of something, anything (it doesn't matter) and turn it all into energy then it will give you A LOT of energy, because (speed of light)squared is a very big number.

this is the foundation of nuclear energy. in using nuclear energy we convert a little bit of uraniums mass into energy, and some left over radioactive material...

Answer 5

This equation, originated by Albert Einstein, means that the amount of energy in joules is equal to the amount of mass in kilograms times the speed of light in meters per second times itself.

The main importance of the equation was that it implied that matter and energy were convertable from one to the other. It also showed that a very small amount of matter contained a very large amount of energy in it.

Answer 6

This is the hallmark equation of Einstein's theory of General Relativity. It basically means that matter and energy are the same, and they can be converted back and forth, but with the proviso that a tiny mass will convert to a heck of _____load of energy.

Answer 7

E is energy
m is mass
c the speed of light


The speed of light by itself is a huge quantity (299,792,458 metres per second). When you square it, it becomes a lot more:

c squared = 89,875,517,873,681,764

Now, notice that c squared is multiplied by mass...

This means that when you have even the tiniest ammount of mass (since it will be multiplied by that huge number) the result of that product implies that all mass contains quite a lot of energy.

Answer 8

It is an equation relating the rest mass to energy. To be more precise, it is written:
E0=m0*c^2

To indicate that you want to refer to the rest mass and not the relativistic mass, or energy. You will less often see the whole equation which is:

E^2 = (m0*c^2)^2 + (pc)^2

This relates the mass with any momentum to the energy. When things are moving they have more energy.

Answer 9

Energy is equal to the product of mass and the speed of light squared.

It explains how energy is converted to matter.

Answer 10

Yep, energy is equal to the ("speed of light" x matter)^2, devised by einstein.