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# E=mc2. Why is that?

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If one has a line, and wishes to transform it to a flat, plane square, another dimension is drawn, and, by virtue of that 'expansion', a new form is created. The area of the new shape? Obtained by multiplying the two dimensions. The new dimension that was drawn is the 'translation factor' there, in obtaining area.

And from a flat, plane square, to a cube: another dimension (depth) drawn. The volume? Obtained by multiplying by the added dimension, that dimension, serving as a 'translation factor', the product, volume. The new, third dimension, the translation factor that results in the product of volume.

So, area (2 dimensions), volume (3 dimensions). And for 4 dimensions -- space. How does one calculate space? Is time part of that equation? I do not know; perhaps unstated (unnecessary to do so), as space and time are inseparable, but always there. (Trafalgar Square does not exist apart from time -- it exists now, it existed in 1990, it didn't always exist, it may not always exist.)

But: E=mc2. I think of it in this way:

Matter, transformed to the other primary form of existence (the two, matter and energy), according to a specified translation factor, that factor being the speed of light. The particular amount of energy, for a given amount of matter, specified by that factor.

E=mc2

Why is the dimension of c squared? No doubt the fact it is accurate has been demonstrated experimentally. But I do not know why it is the case. I need to pick up Einstein.

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Why is the dimension of c squared? No doubt the fact it is accurate has been demonstrated experimentally. But I do not know why it is the case. I need to pick up Einstein.

Energy is denominated in units as M and V^2 where M is mass and V is velocity. Classical kinetic energy is m*v^2/2 and mass to energy conversion relativistically is rest mass times the square of the speed of light. Why is this the case? My guess is that energy is propagated with spherical symmetry in empty space. Many of the physical laws are the consequence of underlying symmetries.

Bob Kolker

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What on earth are you blithering about? The c in the equation is the speed of light, not a DIMENSION. Criminy, if you're going to spout worthless nonsense you might at least want to check your terminology first. The E=mc^2 equation has nothing to do with "space", it simply answers the question of "how much energy do I get if I convert a given mass completely TO energy".

Mother of god.

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For a description of where the equation comes from, see

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Another explanation:

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What on earth are you blithering about? The c in the equation is the speed of light, not a DIMENSION. Criminy, if you're going to spout worthless nonsense you might at least want to check your terminology first. The E=mc^2 equation has nothing to do with "space", it simply answers the question of "how much energy do I get if I convert a given mass completely TO energy".

Mother of god.

Wow, Jennifer! Ya' know, there are decaffeinated brands on the market which taste just as good as the real thing?

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What on earth are you blithering about? The c in the equation is the speed of light, not a DIMENSION. Criminy, if you're going to spout worthless nonsense you might at least want to check your terminology first. The E=mc^2 equation has nothing to do with "space", it simply answers the question of "how much energy do I get if I convert a given mass completely TO energy".

Mother of god.

I think the word is blathering. However, this guy takes blathering to such a new level that blithering might be a good new word.

Talk about your apples and oranges. Cheese and Rice!

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I think the word is blathering. However, this guy takes blathering to such a new level that blithering might be a good new word.

blithering

Web definitions

•Talking incoherently; jabbering

If someone is blathering on about something, they are talking for a long time about something that you consider boring or unimportant.

Edited by dream_weaver
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http://www.google.com/dictionary

blithering

Web definitions

•Talking incoherently; jabbering

If someone is blathering on about something, they are talking for a long time about something that you consider boring or unimportant.

My dictionary says blathering is 'foolish talk especially in great quantity'. That was my impression. They both work.

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To make the thread hijack complete, it appears from the etymology that the term originated from Old Norse blathra - "to talk stupidly", but then converted to blether for much of its English history, before switching back to blather and finally blither as an alternative. Blether fell out of use in the 19th century, right when blither came about.

Edited by brian0918
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To make the thread hijack complete, it appears from the etymology that the term originated from Old Norse blathra - "to talk stupidly", but then converted to blether for much of its English history, before switching back to blather and finally blither as an alternative. Blether fell out of use in the 19th century, right when blither came about.

Why did you bother?

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Why did you bother?

Why not? It's more useful knowledge than what the OP put up for discussion.

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Why not? It's more useful knowledge than what the OP put up for discussion.

I was alliterating and rhyming.

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Nuts, lost in internet translation again!

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Why did you bother?

I like etymology.

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• 9 months later...

All you etymologists are alike!

Is this the Kinetic Energy equation? E = ½mv2?

If so, why does E=mc2 look similar?

Edited by Brian9
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All you etymologists are alike!

Is this the Kinetic Energy equation? E = ½mv2?

If so, why does E=mc2 look similar?

They look similar because energy is in units of mass times speed squared.

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I don´t get it why Jennifer gets all piseed off in this thread.

Dimension doesn´t have to mean a spatial dimension in physics, it can mean any type of quantity that changes in some context. In a math course called Linear Algebra any engineer learns this. You can deal with all sorts of dimensions in systems of equations, but that does´not have to mean that all those dimensions are dimensions of space.

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I don´t get it why Jennifer gets all piseed off in this thread.

I can explain that, but why not ask her directly?

As far as the OP's question, why are we squaring the velocity in the equations, I'm inclined to agree with what Robert Kolker wrote, although I don't completely understand what it means. I read somewhere that the Kinetic Energy equation and Einstein's equation are one & the same. I believe that, but I still don't understand either one. I don't understand them, because I don't know where they come from. But offhand they make sense. In the equations, "energy" is related to the product of "mass" and a velocity squared. "squared" perhaps because the physical thing we are describing is a sphere. I've read that the 1/2 is ignored when you talk about the speed of light, because light doesn't have enough mass that it is so very consequential. But if that were the case, I don't see why we couldn't just write the equation as, E=c2. If half the mass didn't matter, why does the other half matter? So, I really don't understand the equations.

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If you want to know where the formula comes from, see here.

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If you want to know where the formula comes from, see here.

Why? Wikipedia is not my first choice. I'd sooner try to understand the kinetic energy equation, or Einstein's equations from just about any other encyclopedia. Thanks, but no thanks.

Edited by Brian9
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The geometric intuition is correct. Imagine a spherical mass is photon-ized in the absence of angular or translational momentum. Then, to conserve these, the photons produced must be ejected spherically from where the mass was. Measuring out one second in time from the inception of the disintegration of the mass into photons, one ought to have a spherical shell of photons in flight that has surface area of 4*PI*c*c, and an intensity proportional to the mass (assuming a reasonable mass and subsequent large number of photons radially and evenly distributed).

In the case where the mass has translational momentum, the sphere becomes an "ice cream cone" shape, due to doppler effect -- this corresponds to the momentum-dependent term (E=m*c*c only works for rest mass). Other, much more complex forms of equi-time photon shells/embracements are obtained if the mass is not spherical, or if it has angular momentum.

Now, I prefer not to use geometry to analyze micro-context phenomena -- geometry was designed for use in everyday context, and is not suited to explaining the behavior of entities whose translational momentum investment approaches the limit. That's where Einstein pops in, with non-Euclidean geometry as the norm, and space as a complex "stress" tensor depending on the gravitating bodies in proximity to the space considered.

There are probably simpler ways to get to Einstein's point. While perhaps merely suggestive, and certainly not a proof, yet the geometric approach together with the assumption of proportionality between mass and energy yields a useful visualization: photons emanating radially outward as a consequence of explosive expulsion of energy when spherical, non-rotating, rest mass is disintegrated. Then, simply choosing to measure at the same time/distance, the intensity of photonic energy at the chosen radial shell will be proportional to the mass -- how could it not be?

- ico

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• 3 months later...

energy= matter times the velocity of light squared. why did Einstein give this equation when he said light is a constant in the universe? he also stated that matter that travels at or faster than the speed of light will gain mass and slow down. so nothing will never go faster than the speed of light. now the equation says matter traveling at twice the speed of light will turn into energy, and vice-versa. so lets think? twice the speed of light is faster than light, so we have to say matter can travel faster than the speed of light even twice the speed of light before it becomes energy. huh? so now is twice the speed of light a constant? help me I'm confused. Einstein also spent the rest of his life trying to prove that atoms cannot become entangled because it would prove his theory of relativity wrong or would it? because the atom can send its information over billions of light years instantaneously with no loss of time across the universe. The only solution Einstein could come up with was that the only way the information could travel across the universe without a loss of time could only be if the information was not traveling in our three dimensions. so he said in our 3 dimensional universe light is still a constant. so he never could explain how the atoms can share information over billions of light years instantly. This is called teleportation. a quantum effect that we are just now starting to understand. There must be another dimension. what do you think?

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energy= matter times the velocity of light squared. why did Einstein give this equation when he said light is a constant in the universe? he also stated that matter that travels at or faster than the speed of light will gain mass and slow down. so nothing will never go faster than the speed of light. now the equation says matter traveling at twice the speed of light will turn into energy, and vice-versa.

You have completely misinterpreted what is meant by E=mc^2. You should check out the Wikipedia article for an introduction, particularly the section "Meanings of the strict mass–energy equivalence formula."

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