Energy equals mass times the speed of light squared.
124023
It stands for the Latin word celeritas, which in Latin means speed, but in Einstein's actual equation celeritas means the speed of light which is approximately 3x10^8 m/s.
215968
oh, wow, this is a physics question.\n\nto start, we remember E = mc^2\nthe problem gives 4 grams matter and 2 grams antimatter.\nmy solution would be that 2 grams of matter and 2 grams of antimatter annihilate to produce 4c^2 (2 + 2 = 4) energy.\nthe excess 2 grams of matter remains unaffected.\nthe answer is D.
166826
That person was referring to Albert Einstein's special theory of relativity. This theory states that time, weight and mass are not constant. When moving at high speeds, all of these get compressed. The speed of light is the only thing that remains unaltered. That happens because, said Einstein, energy is equal to mass times the speed of light squared, or E = mc2. \n\nNowadays, most scientists accept that if, for instance, an astronaut was to travel for 20 years in space at the speed of light, he would return to find out that people he knew got older faster than he did. \n\nSo, yes, your friend's claim has some grounds...
95687
Light has no rest mass, since it can't be stopped without absorbing it, but it does have a mass equivalence due to its energy.  The energy of a photon of a particular wavelength of light is given by E=(h-bar)(nu) and the mass equivalence of energy is E=MC^2, so (h-bar)(nu)=MC^2, solve for M, and you get M=(h-bar)(nu)/C^2 as the mass equivalence for an individual photon.  It's a really, really small number, even for high energy wavelengths of light, plus light moves very fast past an object which could assert a gravitational pull on in, so light only bends by an observable amount in really high gravitational fields.
30207
If we define the matter as any thing has mass then photons is matter.\nThis is although the rest mass of the photon is zero but it has a mass while running at speed of light
67068
I would have to say no. E=mc^2 is a version of einstein's relativity theory. It means that Energy is equal to Mass times the speed of light squared, and that there is an equivalence betwen mass and energy ( it means that no object with mass can go faster than the speed of light). But it has nothing to do with everything being made of nothing in my opinion. (see http://www.drphysics.com/syllabus/energy/energy.html)
304652
The speed of light is constant, although there are differences in the electron fall rate-things, if that's what you're talking about.
315132
The theoretical physics equation E = mc2 states a relationship between energy (E), in whatever form, and mass (m). In this formula, c², the square of the speed of light in vacuum, is the conversion factor required to formally convert from units of mass to units of energy, i.e. the energy per unit mass. In unit specific terms, E (Joules) = M (kilograms) · (299792458 m/s) 2.\n\nMeaning of the Formula:\nThis formula, which was discovered by Albert Einstein, proposes that when a body has a mass (measured at rest), it has a certain (a very large) amount of energy associated with this mass. This is opposed to the Newtonian mechanics, in which a massive body at rest has no kinetic energy, and may or may not have other (relatively small) amounts of internal stored energy (such as chemical or thermal energy), in addition to any potential energy it may have from its position in a field of force. That is why a body's mass, in Einstein's theory, is often called the rest energy of the body. The E of the formula can be seen as the total energy of the body, which is proportional to the mass when the body is at rest.\n\nConversely, a single photon travelling in empty space cannot be considered to have an effective mass, m, according to the above equation. The reason is that such a photon cannot be measured in any way to be at "rest" and the formula above applies only to single particles when they are at rest. Photons are generally considered to be "massless," (i.e., they have no rest mass or invariant mass) even though they have varying amounts of energy.\n\nThis formula also gives the quantitative relation of the quantity of mass lost from a resting body or an initially resting system, when energy is removed from it, such as in a chemical or a nuclear reaction where heat and light are removed. Then this E could be seen as the energy released or removed, correponding with a certain amount of mass m which is lost, and which corresponds with the removed heat or light. In those cases, the energy released and removed is equal in quantity to the mass lost, times the speed of light squared. Similarly, when energy of any kind is added to a resting body, the increase in the resting mass of the body will be the energy added, divided by the speed of light squared.
521944
Doesn't that have something to do with Einstein's e=mc^2?  It sure looks like it.  The rest of seems to be an example of an explanation of the inefficiency of practical mass to energy conversions.  I could be wrong.\n\nOh, by the way:  what are you asking?
26899
Energy equals mass times the speed of light squared. It means that mass contains a huge amount of energy, which is why just a tiny amount of plutonium results in a huge nuclear explosion.
213584
another one of einstein's equations is as follows:\nrelative mass = original mass divided by the square-root of "1-(velocity squared/speed of light squared)"\n\nyou can better picture the equation by going here:\nhttp://en.wikipedia.org/wiki/Mass-energy#Relativistic_mass\n\nexplained:\nas the object's velocity squared approached the same value of the speed of light squared, the phrase "v2-c2" would approach '1'. causing the entire bottom mathematical phrase to approach '0' because 1-1=0 :) \nas the bottom phrase approaches '0' the relative mass becomes almost infinite because anything divided by something so close to zero would experience a massive increase in value. example: 1/.01=100.  as .01 becomes smaller (approaches zero), the '100'(our hypothetical relative mass) goes -way- up (approaches infinity). \n\nremember that mathematics does not allow division by zero therefore anything having mass cannot attain the speed of light. because the energy required to accelerate near-infinite mass would itself be near infinite.
40805
Einstein believed that the velocity of light was a constant, unchanged since the big bang. He was probably wrong about that, see articles on dark energy to learn why. Since Energy is expressed in joules which is a measure of work - moving one newton of mass one meter-, a measurement in meters per second was needed for the energy equation to solve with the proper units. Einstein believed that the square of the speed of light would account for the most extreme accleration possible and therefore would produce the highest theoretical yield of energy. At least that's what a lot of scientists think Einstein thought. Not a lot of people have had the capacity to think like Einstein so we are all just guessing from his speeches, writings, and calculations what he really thought.
379901
Mass = Volume * Density.
432893
1) At the present speed of light it could be bigger than that.\n\n2) Good point!
417553
No, not really.\n\nEven high school labs now do light experiments that show photons are quanta.  One simple experiment, is with the photometer that emits electrons when struck by light.  The electrons are like billiard balls and the photons are the cue balls striking them to send them on their merry way.\n\nIf light were simply a ray (a force field), the amount of electrons emitted would be proportional to the strength of the light beam.  But they aren't and the number of electrons actually follow a step-function where at a given threshold of light, the electrons suddenly burst forth after none up until that threshold.\n\nThe photon concept, as bundles of energy, is the result of what I would call good physics.  Good physics is physics that starts with the physical phenomenon and then derives equations to explain it.  Bad physics, like string theory, starts with the math and then tries to explain a physical phenomenon, like strings.\n\nAs to your last assertion, think about it...would even physicists, who are renowned for their weird jargon, call something a "matter," which is a synonym for "mass" if it were not a mass?  No, dark matter is a mass...more correctly a mass-energy (due to E = mc^2).  DM accounts for about 96% of all the mass-energy in our known universe.  \n\nUntil just recently, DM has not been observed, which is why they called it dark.  But a recent observation of two galaxies colliding has seen the effects of the dark masses surrounding those two galaxies also colliding.  So, there is now observable evidence that the dark matter exists...the theory has been validated. [See source.]
13238
Photons have no mass, therefore no weight.
3820
Energy equals mass times the speed of light squared.  It's a formula used to calculate the conversion between mass and energy.  For example, an atom has positive protons and neutral neutrons in the nucleus, so how do the protons stay together? well, there's binding energy which actually comes from the mass.  Also, particle physicists have been crashing particles together in a particle accelerator at very very high velocities, and the resulting particle is often bigger than the sum of the two original particles.  This is because some of their energy was converted into mass.  It takes a huge amount of energy to make a very small increase in mass.