Is the equation E=mc^2 universaly proven?Can't anything travel faster than light???
457252
This is equation has yet to be proven incorrect and nothing has been proven to travel faster. However, yesterdays facts can always be questioned through the test of time.
1063094
Being accelerated past the speed of light is impossible because of the nature of momentum.  It is not simply mass times velocity, but mass times velocity times gamma.  Gamma is a factor which adjusts for the fact that as an object's velocity increases, it has more kinetic energy, which, because E=mc^2, is mass.  Gamma is equal to 1/(1-v^2/c^2), where v = velocity and c is speed of light. As the velocity approaches C, v^2/c^2 becomes 1, and Gamma becomes 1/(1-1), or 1/0.  This means a massive particle traveling at the speed of light has infinite momentum.  It takes infinite force to accelerate to infinite momentum, so breaking the speed of light (for a macroscopic object with mass) is, according to current theory and law, impossible.\n\nHowever, other avenues for an artificial increase of speed are possible.  You mention a lot of them, and not much is really known about them, but it could be possible to warp space-time to let us effectively travel faster than light (like the warp drive in Star Trek).
639238
e=mc^2 \n(energy equals mass times the speed of light squared).
1168590
Let's look at E = mc^2.\n\nE is energy. It is measured in joules.\nm is mass. It is measured in kilograms.\nc is the speed of light. It is measured in meters per second.\n\nKilograms multiplied by (meters per second)squared are joules. If you don't have a mass multiplied by the square of a velocity (or something with equivalent units), you don't have energy.\n\nThe maximum speed any mass can have is infinitesimally less than the speed of light. c^2 would be the square of that speed.\n\nNow, let's consider the practicalities. Experimentally, we find that, as we accelerate something very close to the speed of light (which is done every day in particle accelerators, for example), it becomes harder and harder to accelerate the closer it gets to the speed of light. E = mc^2 is the energy of a mass at rest; this is where the energy of nuclear weapons and nuclear power plants comes from. As an object moves, its energy is multiplied by a factor usually abbreviated with the Greek letter gamma; its value is:\n\ngamma = 1/[1 - (v/c)^2]^1/2\n\nSo it's 1 over the square root of [1 minus (v/c)squared].\n\nAs v becomes closer and closer to the speed of light, v/c becomes closer and closer to 1, the denominator of the fraction becomes closer and closer to zero, and gamma becomes larger and larger. If v were to equal c, gamma would be infinite. This is why you can't accelerate any massive object to the speed of light - it would take an infinite amount of energy. \n\nSo, you may ask, what about photons? They go at the speed of light, don't they? Indeed they do. They manage this because their mass is zero, and they can never travel at any speed other than the speed of light.\n\nIncidentally, it is indeed true that m = E/c^2; this is often useful in physics calculations.
262909
Not quite exactly right, Flavio.  \n\nTrue the speed limit for an object moving in space is the speed of light in a vacuum, but a number of proposed methods for "warp" type travel have been developed which don't violate general relativity.  A few years back a physicist named Alcubierre (I think I have the spelling right) produced a solution for Einstein's equations of spacetime which would allow a warped region of space to move arbitrarily fast relative to surrounding space.  Within this warp there can be a region of flat spacetime which would be carried along with the warp.  I've read his paper on it and it's very clever from a mathematical and theoretical point of view, but it's completely impractical given our level of technology, and it also makes some assumptions about things that we simply don't know whether or not they're possible.   Unfortunately, Alcubierre's solution requires tremendous amounts of both positive and negative mass.  "Negative mass" could also be provided by something like dark energy, but then there's the question of what exactly that is.  Its gravitational effects are seen in the universe, but the identity isn't known, and nor is it known how to vary it.  Dark energy could be the result of the zero point density, or it could be a phenomenon that is variable, in which case it's often called "quintessence".  Heim theory, one of the more unusual approaches to a grand unified theory, uses a quintessence instead of a fixed dark energy density, and furthermore predicts the density of quintessence will be related to rapidly moving strong magnetic fields.  \n\nSo, general relativity does allow for a "warp drive" solution, but the spaceship being moved isn't actually moving at above the speed of light but rather is being carried along by the expansion and contraction of spacetime in the warp.  Relativity says that no object with a rest mass can exceed the speed of light (things with no rest mass, like photons, must move at the speed of light in order to exist), but spacetime isn't an object nor does it have an inherent mass.   So, yes, it's hypothetically possible at this point, but there are a whole lot of things we'd need to understand in order to even begin to think about how to engineer such a system, and additional knowledge about phenomena like dark energy may show that it can't be done.  Right now it's still a plausible idea, but this may only be because we don't know enough yet.
8700
no. well, its absolutely impossible to travel at the speed of light, but lets pretend you can so i can actually give you an answer to the question. The speed of light is actually the ultimate speed limit to the universe, nothing can travel faster than light, so although you would expect the light to be going at twice the speed of light (you plus the speed of light)it can't because it is physically impossible for even light to travel faster than the speed of light so it would be going at the same speed of you and not reach any path in front of you.  Of course, if you turned on your headlights before you started moving, the light would always be one step ahead of you.\n\nbut again, this situation couldn't happen anyway since you can't get to the speed of light, and if you want to know why, look at some of my answers to other questions about time travel (which involves velocity distorting time) and shining flashlights and such.
292835
According to Einstein's Theory of Relativity, E=MC squared, where E is energy, M is mass, and C is the speed of light, in order for something to approach C, it must have very little mass and a hell of a lot of energy.  However, if something has enough energy to approach the speed of light, its mass would be infinite. This means that even if you weigh 0.00000001 grams, which is basically nothing, when you approach the speed of light, the infinite energy that you have will make your mass infinite also (if you don't already burn up, that is)...you'll weigh more than everything in this universe combined.  You'll rip a hole through this universe like a heavy piece of weight through a thin piece of paper, then you'll be like a black hole sucking everything in.  However, since the energy in this universe is limited (and not infinite), if you somehow can harness ALL the energy in this universe to use for travelling, you'll only move as fast as the speed of light...that is, there's simply not enough energy in this whole universe to allow you to go faster than light by even .00001%, so we're basically "trapped" in this universe, unless we can find an alternate "exotic" energy source from another universe to use, or somehow "bend" space so that we can go from one point to another instantaneously. Now, photons are "light particles" that travels AT the speed of light, so they are the fastest things in this universe, so you may be wondering, "Well, since they travel as fast as light shouldn't they be very heavy also?"....and the answer is NO !!!   because although photons have the exact amount of available energy to travel as fast as light  (because they ARE light), they have absolutely zero mass....That's why when you shine a flashlight at your friend's forehead while he sleeps or something, you won't punch a hole through his head....because photons weigh NOTHING.
28019
no. and light does not have mass. light is made up of little packets of energy called photons which are massless.\nthis is why it can't: lightspeed is the ultimate speed limit of the universe. nothing can go faster then the speed of light because in the formula for time dialation(time slows down for an object moving close to the speed of light) t'=t/sqrt(1-v^2/c^2) where t' is the time passing for an outside observer, t is the time that passes for the object going at the high velocity, v is velocity, speed is the speed of light and ^2 is squared. (note: this formula is definately correct, it's part of einstein's theory of relativity and I've had to derive it myself for class) so if v was bigger than c, you would have a number greater than one and therefore a negative number under a square root, which is impossible.
600967
No there is no 'summation' of speeds involved with light.  Light is Electro-Magnetic Energy, although light travels as particles as well as waves.  In this Universe the speed of light is a constant, roughly 186,000 miles-per-second, or 300,000 km/sec or 300 Mega-Metres / sec.  Unless some POWERFUL external force acts upon light, it cannot change speed.  This entails the gravity of black-holes and such. (Not even light can escape from them.)\n\nA vehicle might weigh somewhere in the neighbor-hood of 3,300 lbs. (Approximately 1,500 Kg, for those of you who have not learned to count properly, just yet ...)\nCheck out da' math ...\n\n60mph = 100 kmph = 27.77r mps. \n(1,500 Kg x 27.77r mps) / 9.81 mps = ~ 4,246 N\n\nI doubt, very seriously, that a little over 4,000 Newtons is enough force to even put a dent in the factor of light-speed.  For more info, look-up Einstein's Theory of Realtivity' (Although I believe 90% of it to be short-sighted ancient crap ...)  This subject is covered in it ...\n(umm covered in Einstein's Theory, not copvered in crap .. which err .. is the same thing at times ...
182197
Disregarding the pseudoscientific ramblings above, use Einstein's energy equation which states that the energy of a particle is the magnitude of its momentum 4-vector, E^2 = (mc^2)^2 - (pc)^2. Since the photon is massless, this becomes E^2 = (pc)^2, and we get the momentum of a photon as directly proportional to its energy p = E/c. \nDon't be reluctant to use the equations, and don't try to shoehorn Newtonian mechanics where it does not belong (speeds at or near the speed of light). In this case, you are using the fallacy that classical momentum mv applies to a relativistic object. For more information about similar fallacies, see the second source below.
336972
Wow, great question(s)!  You're brooding over something called the 'twin's paradox', read more about it in the link below.  Basically, what you're fretting over are a couple of the (wierd) implications of special (and general) relativity.  You (and what some others have said) are right, all velocity is relative, which comes from the simple fact that there is no special place that we can call 'still' which we could measure our velocity against.  The single exception to this lies in the speed of light, which is constant for everyone everywhere, no matter what their speed is relative to anything else.  (Note: light isn't special, the only reason it's able to travel at the upper speed limit is because it's particles, photons, have no mass.  Nothing with mass can ever travel AT the speed of light, only near if it is pumped up with huge amounts of energy.)  Think about the wierd implications of this; even if you were able to travel at 99.999999% the speed of light, and your friend would also be able to travel the same speed in the opposite direction, if you shined a light back toward your friend and could measure the photon's speed as they travelled between you the photons would STILL be travelling at the speed of light.  Ok, what does that mean?  The speed of light is just a speed, like any other, but is a constant that can not be exceeded.  Well, like any other speed, c (the usual symbol for the speed of light) is definded as the ratio of the distance travelled (call it 'x') by the time it took to travel it (call it 't'), or c=x/t.  But if 'c' can't change (because it's a constant) what is changing?  There's only two other things in the equation, x (the distance, a measure of space) and t.  Time and space enter into Einstien's equations here, the only way to keep c constant is for x and t to somehow collaborate to change together to make it so.  This is why time (and space) are so 'relavent' to velocity.  And as a matter of fact, time is 'relavent' to gravity as well, as Einstein pointed out so much better than I can.  For Einstein, the breakthrough came when he realized that there is no measurable way to distinguish between gravity and acceleration (a.k.a. the rate of change of velocity with respect to TIME), or more importantly, between the lack of gravity (say a person floating in space) and a particle (or person) in a falling box, they're indistinguishable.  From these two simple ideas (the constancy of c, and the equivalence of gravity and acceleration) Einstein formulated the theory of general relativity, one of the crowning achievements of human thought.  You ask good questions, keep wondering!
72176
If you're asking about some mass being accelerated up to and beyond the speed of light, no it is NOT possible. Einstein theorized that the faster an object moves, the greater will become its mass. This increased mass would require more energy to accelerate it even more, which in turn would increase its mass, which would require more energy to go faster, etc., etc.,. Ultimately to get this object up to the speed of light would require infinite energy, and that's impossible. This isn't just theory anymore either; mass increase versus velocity has been observed countless times in modern particle accelerators.\n\nOf course there are plenty of sci-fi novels, TV shows and movies (like Star Trek and warp drive) where things move faster than light, but unless someone can find a way around Einstein and all the evidence that he was right we'll never be able to attain FTL travel.\n\nBy the way...worm holes don't provide a way to MOVE faster than light. So-called worm holes, if they exist at all, are nothing more than short cuts; going through a worm hole you'd still have to obey the speed limit imposed by Einstein.\n\nPersonally I hope that some day some radically new branch of physics is found that would allow us to get around Einstein, but right now it doesn't look too good.
51835
The physics community thinks not, but that never proved anything. The assumption is that nothing can travel faster than light. The answers are usually along the lines of, "since quantum entanglement happens instantaneously, its faster than light, but nothing can travel faster than light, so its impossible".\n\nThere may come a future theoretical structure in which lightspeed is surpassed under some circumstances, without temporal repercussions, then this assumption does not hold.\n\nI would add that I think its possible, based on an experiment described in Brian Greenes fabric of the universe that he uses to explain that its not.\n\nIts a simple extension of the two slit experiment where, immediately after the slits you use a photon doubler to create two entangled photons for each one passing through the slits. One for each slit. One photon carries on, the other is bent off at 90 degrees using a half silvered mirror and sent a long distance.\n\nIf no measurement is made on this second photon,, the other photons act as waves and you get an interference pattern. If a measurement is made, they act as particles and you get hotspots behind each slit.\n\nMy extension is that, by choosing to measure the photons that travel a long distance, you can instantaneous make the photons produce an interference pattern or not. Such a pattern would be noticable. If the split photons have travelled many light years, this pattern should be formable in a few seconds, so the message is coded in interference / non interference. Much like morse code in dots and dashes.
635609
E=MC2 describes the potential energy in all matter. Since C is the speed of light, and C squared is a HUGE number, there is lots of potential energy stored in all matter.\n\nThere isn't really a practical application unless you're building an atom bomb or a time machine.
15796
Its not proven but heres how eistine put it.\n\nThe faster you travel the more you weigh. Since light is the fastest moving thing in the universe if you went faster then that you would way infinite pounds and that would be impossible so you cannot go faster than the spped of light
394861
I have no idea. But Steven Hawking says we cant travel back in time, and Einstein showed that hitting the speed of light with a mass is pretty unlikely. But that has no effect on the massless.\n\nAnd E=MC2 is just the rest energy of a particle of mass M and has no time travel implications.\n\nI know Cal-tech has some research in this field... look into it.
612849
NO energy, matter, or information has EVER been observed to exceed the speed of light.\n\nTheoretically, there are particles known as "tachyons" ( see wikipedia ) that travel ALWAYS in excess of that of light but never AT or BELOW that speed. Although never observed, their theoretical existence has sent many physicists to look for them ( or their trails ! ) \n\nthere are many abstract entities that "travel" faster than light.  for example, the shadow of a large celestial object ( a planet say ) on another celestial object can be observed to move at great speeds.  a shadow however is not a real entity ( i.e. mass or energy ) and it cannot convey information.