what is E = MC**2 mean really?

Answer 1

Energy = Mass X the speed of light (squared)

Answer 2

Argh...there are a lot of misleading answers here.

First, the C**2 does not mean the mass (M) is traveling at the speed of light. C is just a constant multiplier in the equation like G in GMm/R**2 in the force of gravity equation or Planks constant (h) in the wave energy equations or many of the other constants we find in physics.

Second...gamma? Where the heck did that come from? Looks to me like that answerer is trying to fold the Lorentz transform into E = MC**2, which is the proper thing to do...but gamma? For one thing, if g = 0 for rest mass in that answerer's equation, that mass would have no equivalent energy (zero times anything is zero)...and that is simply not the case. Even rest mass has equivalent energy...the atomic bomb is based on that fact. Those atoms in a fission or fusion bomb are rest mass atoms...the energy comes from the differences of the masses, before and after fission or fusion, not the speeds of the masses.

Finally, E = MC**2 simply means there is an equivalence of E energy in a mass M. So, for example, you have one atom with 1 AMU (atomic mass unit) mass. Now you split that atom into two parts, each having .45 AMU mass, which is a total of .90 AMU between the two split parts. What happened to the missing .10 AMU...it turned into energy according to E = MC**2 where M = .10 AMU the missing mass. And, again, these masses are rest masses, they are not going the speed of light or anywhere close to it.

Answer 3

It means that mass is simply concentrated energy, even at a complete rest. By itself, the equation is not terribly interesting, even Eistein thought it was a neat trick, but nothing ground breaking. What it does mean is that there is enough energy in your thumb to make an explosion the size of a hydrogren bomb, if you can just convert all the mass to energy very quickly. Fortunately, that's not so easy except with radioactive materials.

Answer 4

Simply, in any reaction in which a change in mass happens and corresponding energy is released ... the amount of energy equivalent to that mass change is MC^2, and vice versa.

Answer 5

Energy = Mass x Speed of light squared.

Answer 6

This equation states that the energy and mass are interchangeable for a body traveling at the speed of light. This is a small contradiction against the laws of conservation of mass and energy viewed individually.

Speed of light .. here is another big paradox .. how do you measure the speed of a body traveling at a speed higher than that of light? Hypothetical or not ..

Answer 7

E is energy
m= the mass of that particle/ group of particles
c= the speed of light in void

it means that for example if u have a dynamite and it explodes, the energy generated is the mass of the dynamite*c^2

Answer 8

This is Einstein's most famous equation. It relates energy with mass.
E is the amount of energy in a particle.
M is its mass.
C is the speed of light.
This equation was the first step toward special relativity and is actually incomplete. There is an extra factor g(gamma) that compensates for the velocity of the object. At rest gamma is 0, at the speed of light, gamma is infinity.
The corrected equation is
E = gmc^2

Answer 9

It means mass and energy are inter-convertible, with the above equation giving you how much mass (or, energy) you will get for a specified amount of energy (or, mass).

Answer 10

It means that mass is simply a different manifestion of energy. Energy is mass and vise-versa. They are different manifestations of the exact same thing.