e=mc2: 103 years later, Einstein's proven right

November 20, 2008
People walk past a giant sculpture featuring Albert Einstein's formula E=mc2
People walk past a giant sculpture featuring Albert Einstein's formula "E=mc2" in front of Berlin's Altes Museum in 2006. It's taken more than a century, but Einstein's celebrated formula e=mc2 has finally been corroborated, thanks to a heroic computational effort by French, German and Hungarian physicists.

It's taken more than a century, but Einstein's celebrated formula e=mc2 has finally been corroborated, thanks to a heroic computational effort by French, German and Hungarian physicists.

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2.3 / 5 (11) Nov 20, 2008
Albeit using a computer model. So until the model is proven to be correct the results have to be validated some other way.
3.8 / 5 (8) Nov 20, 2008

I think that they solved the field equations using data collected from experiments (they do not say that, though) and found out that the E=MC2 is correct. My guess.
2.1 / 5 (9) Nov 20, 2008
badly written article. Hard to follow. I dont think they corraborated Heim's theory.
2.5 / 5 (8) Nov 20, 2008
Could there be a simple explanation to the origin of mass? The link between mass and energy may be as simple as a link between linear and angular momentum. Consider the smallest unit of momentum as a basic unit of force. A basic unit of linear momentum collides, at the speed of light, with an equal but opposite linear momentum turning both into angular momentum. Angular (gyro) momentum is resistant to change in movement. Could this be the origin of mass? Reversing the process turns mass into two units of momentum which plus time, is energy. This is explained in a Book titled "An Alternative to the Standard Model of Physics".

3.2 / 5 (6) Nov 20, 2008
i don't think it's badly written at all. obviously, the experimental results and relevant calculations are in the paper.

all they're saying is that they have lined up relativity as applied in cosmology with the same physical "law" as it is observed at the subparticular level-- the raw mathematical equivalence of matter and energy, so to speak.

but i dunno; i imagine you just have to read the paper.
3 / 5 (8) Nov 20, 2008
someone's always plugging something on here.
1.5 / 5 (8) Nov 20, 2008
Not only is the English diction abominable,
this `newstory' is the epitome of hype & BS...
Any modern physics text will tell you that E=mc^2
was verified decades ago.
Wilcek has repeatedly emphasized that the mass of nucleons is due to the kinetic energy of the quarks & gluons. Really, this is no big deal. PhysOrg needs to can this writer...
4.3 / 5 (6) Nov 20, 2008
I have been having trouble logging onto the US Journal of Science website as of this writing to view an abstract (if it is available). However, I have to say that I find it hard to believe that Laurent Lellouch's work was at all about validating E=mc2. First of all, E=mc2 is a derived result, it is not fundamental like Maxwell's Equations for instance. Second, you don't verify a physical model with a numerical model (which is usually based on physical models) you verify them with real world experiments.

It seems to me it would be the other way around: the validity of the numerical results of the numerical model would be confirmed by e=mc2 for the proton.

I am guessing that the really interesting aspect of this research is in the progress made in modeling QCD with lattice-based numerical models, a topic only mentioned in one sentence at the end.

Either this article was written with way too much license, or I am missing something.
2.3 / 5 (3) Nov 20, 2008
"Second, you don't verify a physical model with a numerical model (which is usually based on physical models) you verify them with real world experiments"

Yeah, what he said.....
1 / 5 (6) Nov 21, 2008
Actually, the correct formula is:
E = MC^2 plus 0.1

Have fun!
3.8 / 5 (4) Nov 21, 2008
i guess i WAS missing something. i think this New Scientist article is better:

3 / 5 (6) Nov 21, 2008
Can energy exist without the presence of matter?
4.5 / 5 (4) Nov 21, 2008
This article was badly written is all. The science is fantastic and their methodology was a unique and clever approach to studying Quantum Chromodynamics. The researchers in this case used a technique called Lattice QCD in which they can essentially model quark-gluon interactions as a grid of separate points. This approach makes the problem polynomial in computing requirements.

Once the LHC comes online and the Higg's Boson is found then this work will be largely verified by empirical results :-)
4 / 5 (2) Nov 21, 2008
Can energy exist without the presence of matter?

If you consider particles of zero mass to be not matter - yes.

example : photons (radio/microwave/Infrared/visible/UV/X-ray/Gamma Ray and everything in between)
2 / 5 (4) Nov 21, 2008
i guess i WAS missing something. i think this New Scientist article is better:


That just makes the model worse. They admit that they had to cut corners in order to get a solvable problem. Depending on the choices the results could be either gold or lead (and given Quantum probability it could be both.)
not rated yet Nov 21, 2008
Poincare said e=mc2 first -
2 / 5 (3) Nov 21, 2008
And I was hoping for an article about Gravity Probe B.
Nov 21, 2008
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5 / 5 (3) Nov 21, 2008
here's another for what it's worth, this time from the AAAS online news service:

2 / 5 (4) Nov 22, 2008
On the topic of E=mc2. This article makes a mistake that everybody-- physicists, popular media, even Einstein believe it or not-- makes. The statement that E=mc2 says mass can be converted to energy is wrong. This is not what E=mc2 says. It says that mass and energy are the same thing. Where you have one, you have the other.

The classic application of this misunderstanding is in a nuclear bomb. It is commonly said that a nuclear bomb converts a little bit of mass into energy. But this is not true. It is understandable, because those making the statement simply focus on the rest mass of the atomic nuclei before and after, they don't consider the mass of all the release energy, including the kinetic energy of the nuclei themselves.

The proper way to think about it is with a closed system. Put a nuclear bomb in a giant black box and measure the mass of the black box (which includes the mass of the bomb inside). Now detonate the nuclear bomb, and measure the black box mass again. There will be no change in mass. This is because no mass is converted to energy. That never happens. The black box contains all the energy released, and since it is a black box, the only way to measure this energy is via the mass measurement of the black box.

The black box that makes up an atomic nucleus before fission has nucleons of like charge held incredible close together by the strong force. In other words there is a lot of potential energy. We see this potential energy from the outside as reflected in its mass. We have no other way currently to measure this potential energy, other than by measuring its mass (there might be a way someday, who knows). When a nuclear bomb explodes it is simply converting potential energy into kinetic, thermal, etc. energy.

Sounds dull, doesn't it. Doesn't sound right. Everybody, including physicists always saw mass is converted to energy.

It is incorrect to say this.

Incidently, physicists never do the physics wrong. They always apply the equations correctly, so my statement is not that they don't know their physics. It is only that this statement is incorrect and yet everyone always seems to make it anyway.

Personally, in describing relativity, I think it is very important to make the point that mass and energy are the same thing, and not carry on the misconception that mass is converted to energy, and vice-versa.
Nov 22, 2008
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1 / 5 (3) Nov 22, 2008
I already addressed Alizee's first point with the black-box around the nuclear bomb. There is no change in mass of the black box. No physicist would dispute this.

To Alizee's second point (if I understand it, which I am not sure I do), I'll narrow the scope to clarify the point: physicists use the mass-converted-to-energy characterization all the time.

A common place where this occurs is when talking about high energy physics and the annihilation of a particle with its anti-particle. The brief resulting high energy photon is often characterized as pure energy. But, again, if it were in a black box, you would measure this energy as mass. There would be no change in mass of the black box, before and after an annihilation contained within.

Energy just changes forms. Mass does not disappear and energy appear. With the right containment, energy content of the system will always be measured as mass, no matter what the form of the energy, including whether that form includes particles such as photons without rest mass. When in a black box the energy of a photon is measured as additional mass of the black box.
2 / 5 (4) Nov 22, 2008
To state my point in another manner, this is not some semantic game that I am playing. This is about what the fundamental physics described by the theory of special relativity and its derived equation, E=mc2, says about the physical world. This physics is the revelation by Einstein that mass and energy are the same thing, and not that mass can be converted to energy.

For the record, it is easy to see why it gets characterized this way, but the fact is it is a mischaracterization (by physicists themselves).
not rated yet Nov 22, 2008
This physics is the revelation by Einstein that mass and energy are the same thing, and not that mass can be converted to energy.

Excellent. I remember learning something about this in my physics classes (many years ago :-)) Often we have constants in our equations not because of some intrinsic property but because our system of units are "historically defined".

The c^2 term is just a constant in the equation - actually if unit definitions are chosen a bit differently, the constant disappears and equation is simply what you stated: E = M. Energy and mass have exactly the same units - they are different forms of the same thing. The topic to explore for this concept is quite illuminating and can be found under the topic "natural units". Check out:


wiki links:


not rated yet Nov 23, 2008
May i make the devil's advocate and ask, since the mass of quarks makes only the 5 percent of the measured mass of a proton and the rest is energy, how do we know that in a nuclear reaction such as fusion mass is turned to energy and not that energy is released from that 95 % caused by the interaction and movement of quarks?

And since such a high percentage of the perceived mass is actually energy, how do we know that mass actually exists and that it is not just a condensed form of energy, and therefore everything is energy in reality?
not rated yet Nov 23, 2008
on day, when we get our next break through, einstein will look like he wasnt even all that amazing.
Nov 23, 2008
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Nov 23, 2008
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Nov 23, 2008
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not rated yet Nov 26, 2008
I have been away. Sorry. To answer Linktothepast:

The problem is your question is framed completely in the language of mass being different than energy. Mass and energy are the same thing. Try rewording your question to me, without differentiating mass and energy.

Where you have one, you have the other. So whenever you are saying there is mass, you are saying there is energy-- always. No matter what the form of energy, theoretically we will be able to detect its mass (practicality of a measurement, is another question, of course).

There is both potential and kinetic energy of the quarks within the proton. We have no tools to measure either of these energies directly, although through QCD theory and powerful numerical computations (what this article is about) we can calculate them. Currently, the only way we can "see" this energy is by measuring its mass.

Note that there is nothing to preclude theory from providing us a way to directly measure these energies in the future without having to calculate them or infer them via a mass measurement. For instance, we might discover a way using neutrinos (Fermilab is going to probably become dedicated to playing with neutrinos) to probe inside a proton and get meaningful measurements of kinetic and potential energy someday. We can certainly use theory and measurement to obtain the potential energy of a man standing on a mountain, or a wound-up spring toy. We just currently don't have a way with the proton. But E=mc2 and QCD tells us this energy is there in one form or another. This new numerical calculation now gives us an understanding of that form. Someday we may probe it directly.

E=mc2 is saying the total energy of a system can be measured as a total mass. The total energy of a system is the sum of its kinetic, potential, and rest mass components. Any of these can be zero-- including have particles with no or small rest masses, and we can still measure the mass of the entire system. If binding energies are high (lots of kinetic and potential energy in the bound state) that mass will be quite significant, and can easily overwhelm the rest mass component.
not rated yet Nov 26, 2008
A cleaner way to state what my point has been in a thought experiment in the succinct language of the physicist:

Put a nuclear bomb in a closed system. Measure the mass of the closed system. Detonate the bomb. Measure the mass of the closed system again. There will be no change in mass.

In the above, try it with a particle and an antiparticle instead of a nuclear bomb. It works the same.

When physicists say that annihilating particles creates "pure energy," what they are really saying is that for a finite period of time, all energy is in the form of an extremely high energy virtual gamma ray.

You can always, in theory, detect the mass of the gamma ray.

Mass doesn't go away, and energy appear and then vice-versa-- ever!
not rated yet Nov 26, 2008
Look at this web site for the Nova on the anniversary of E=mc2 and listen to these physicists reflect on E=mc2


They almost all say it wrong.

I am not indicting anyone, or trying to make myself look grandiose. I have nothing more than an undergraduate understanding of SR, although I did take a junior level course dedicated to Relativity (S and G). This course explored SR in depth. I solved plenty of problems with it, and I am confident in my understanding.

I wasn't exposed to this misconception in this class. I didn't realize it on my own. I learned about it at a lecture series at an aerospace firm in Boulder, CO. A guest lecturing physicist described the misunderstanding, and the efforts to correct it in the education cycle. This was over 10 years ago and I have detected no abatement in the use of this statement.

Don't take my word for it. Examine it with due skepticism, and if you come to the same conclusion, then pass this understanding along.

This kind of problem actually is not uncommon. It is almost certainly an issue that is addressable by cognitive science. It is a human nature issue, and we are all always susceptible to it.

I will leave this next statement to you and Google: the Bernoulli principle does not explain airfoils. The heat generated by this statement is intense. There are generations of flight instructors that consider it complete bunk. NASA has gotten in the middle of it. But in the end, the physics simply doesn't support it.

I don't go around looking for these kinds of things to prove I am smarter than everyone else. I am only interested in what is fundamental, and in how science progresses. Cognitive traps can hinder the progress of science. Bohr forbade the metaphysical exploration of quantum mechanics beyond his interpretation. Those that did anyway were ostracized, and relegated to the fringes, if their careers were destroyed. Bohr wasn't bad, he just didn't have the tools. Today we talk about the multiverse. Why can we talk about it today, but the physics community wouldn't tolerate it yesterday? New physics? No. New epistemological under-pinnings in the philosophy of science. The philosophy of science matters. Cognitive science informs the progression of science.

The discipline of science itself is evolving. We have to learn to recognize these kinds of issues, and find a way to keep the natural cognitive processes of our minds from hindering progress in science. When we find issues like these, we have to figure out how to quickly recognize them, and correct them.

If we have trouble communicating E=mc2 amongst ourselves, how do scientists ever hope to communicate properly and effectively the science of global warming to the public and to policy makers?

Nothing is as simple as it seems.
not rated yet Nov 26, 2008
Einstein's work *was* amazing (ref Zevkirsh above), and will always be amazing (he isn't a God, though). None of this is about tearing anybody down, or making anybody look brilliant. It is simply a discussion.
1 / 5 (1) Nov 26, 2008
Einstein's equation, E = mc2, is routinely confirmed in nuclear reactions. This equation and nuclear mass data also revealed that repulsion interactions between neutrons - an overlooked source of nuclear energy - power the Sun and the cosmos.

The 3,000 mass data points and their implications for astro- and solar physics and cosmology were first published in 2001 ["Neutron repulsion confirmed as energy source," Journal of Fusion Energy 20 (2001) pages 197-201; "The origin, composition, and energy source for the Sun," 32nd Lunar & Planetary Science Conference, Houston, TX, (12-16 March 2001) abstract # 1041]. See: astro-ph/0411255
1 / 5 (1) Nov 27, 2008
I'm sorry to tell the person who is repeatedly saying that mass and energy are the same that they are wrong, but mass is measured in the SI unit of kilograms while Energy is measured in the SI unit of Joules or more simply (meters^2)Kilograms(seconds)^-2. Maybe I'm thick, but mass doesn't equal energy directly. One cannot measure the energy of a motionless object. In a vacuum devoid of gravitational pull an object of 0 velocity has 0 potential energy and 0 kinetic energy. All einstein's equation proved was that mass has the potential to be converted into energy by the use of velocity. Conventional laws such as the laws of conservation of matter and conservation of energy state that neither matter nor energy can be created or destroyed. That doesn't mean they equal one another. Matter changes form due to change in temperature, though we measure it via the same unit. Einstein's equation says what physicists have been saying, and that is Mass can be converted into energy and vice versa. Einstein's equation says that at his ultimate speed, the zenith of of energy one can convert from matter is given as Energy equals the mass multiplied by the square of the speed of light. Not, Energy equals mass. Without velocity energy cannot exist. Without the variance in displacement divided by the variance in time, mass would not, of course only theoretically and mathematically at the given time, have any energy what-so-ever. With respect to the black box closed system, you are essentially saying that mass and energy are not the same, but rather energy is calculated by its mass. Also it is my belief that Einstein's equation for calculating energy from mass is flawed, however the instruments of today and mayhap even tomorrow will never be able to verify whether or not my own conception of how mass is transformed into energy is true.
Dec 06, 2008
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not rated yet Dec 06, 2008
Addressing Ashman555's point.

(An aside: I am not implying anyone is "thick" or stupid. My apologies if anyone has taken offense. This is not my intent. I don't pretend to be some physics genius. I am confident, though, that I have a solid understanding of SR, as I have solved lots of problems in it. I am just trying to do my part to fix a glaring error made over and over again by the most prominent physicists. [They don't do the math of SR wrong, or we wouldn't have the LHC. They just routinely state the physics incorrectly in natural language.] Anybody is free to take or leave the argument I am making. My personal belief is that the physics should be stated correctly, even if it doesn't sound as sexy.)

The proper way to state it is that mass and energy are equivalent. If you can measure one, then you know that if you *have the technology* you *will* be able to measure the other. Its true, the unit of measure isn't the same. That is *exactly* the point of E=mc2. c2 is just a constant of proportionality that converts the units between one and the other. As a mathematical equation, E=mc2 could map to many *physical* interpretations. For instance, it can map to a physical interpretation that you start with energy X, you do some physical process on this energy, the energy goes away, and sitting in its place is a mass Y, where Y=X/mc2.

My statement is that this is *not* what it is saying. It is instead saying, if you measure Energy X (say, the potential energy of a man standing on a mountain, by measuring his height), then you will also be able to *in theory* to measure the mass of that energy. The mass you will then find is equal to X/mc2.

These are two completely different statements about the physical interpretation of E=mc2.

The key to all of this is that the "classical" conservation laws always contain the statement of context of being in a closed system. The conservation of mass and conservation of energy laws in Newtonian physics are in the context of a closed system-- systems that contain all of the mass or energy products prior, during and after a physical process takes place. In the case of SR, this is the source of the confusion-- sloppy consideration or understanding of the closed system. If you don't carefully consider what constitutes the closed system, it can "appear" that mass is converted to energy. E.g. the mass of atoms before a nuclear explosion don't add up to the mass of the atoms after the explosion. This is true, but in the context of SR it is incorrect to take the rest mass of the elements before and after as the sole components of the closed system. The velocities of those atoms, the photons, the neutrinos, the thermal excitations, etc. all must be included in the closed system, or you are incorrectly framing the problem.
not rated yet Dec 06, 2008
Addressing Alizee's last comment:

The point that *I* am making is really independent of the source of the physics. It is about the physical interpretation of the the mathematical statement, E=mc2, and nothing more.

Having said this, I have not explored the origins of E=mc2, and your comments have piqued my interest to do this some time. There is no doubt in my mind that the genesis of E=mc2 could be found in other areas, prior to Einstein's work. This type of thing is much more common in the "real" history of science than our common narratives often let on. It says less about any particular scientist than it does about our process of developing the narratives of the history of science.

Hopefully, some day we will get to a point where we place value in getting our narratives to match reality. I believe that holding this as a disciplined value will dramatically improve the communication between scientists, policy makers, and the general public. I believe, in fact, that it will lubricate the process of scientific progress itself. It is much easier to come up with a simple narrative, than to spend the time to develop a thoughtful narrative, that accurately brings complex ideas to those without the training. But without making the effort, in my view, we exacerbate misunderstandings. And when it really counts (say with global warming) we end up with a big, unnecessarily polarized mess.

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