If light rays can be manipulated to move faster or slower than the speed of light...?
144613
light rays do not move faster or slower than the speed of light.  the speed of light is the speed of light, period.\n\nthat said, light often travels *slower* than c, which is a constant defined as the speed of light IN A VACUUM, approximately 3x10^8 m/s.  here is a way you can actually observe some honest-to-god light traveling slower than c:\n\nstep 1.  find a window.\nstep 2.  look at it.\n\ncongratulations, you have observed light traveling slower than c.  in ANY medium (air, glass, water - you name it) the speed of light is slower than the speed of light in a vacuum.  \n\nin fact, the so-called index of refraction (n, which equals 1.4 for glass) is defined as the ratio of c to the speed of light in that material.  generally, denser materials have a higher index of refraction, and people have been able to make light go REALLY slow by making some very dense materials.  all of this is perfectly consistent with general relativity.\n\nas for FASTER than c:  under certain conditions, it is possible to make photons with a "phase velocity" that is greater than c.  however, when people speak of the speed of light, they usually refer to the "group velocity".  the distinction between phase velocity and group velocity is kind of technical; but phase velocity refers to the speed at which the individual phase fronts propagate through space.  \n\nit is possible to make these phase fronts go faster than c; but because the energy or information or whatever carried by the light travels at the group velocity, the actual speed (as far as stuff like general relativity is concerned) is still less than c.\n\nanyway, all of these results are entirely consistent with general relativity.  in fact, i don't know of any published results of a scientific experiment which are not consistent with GR.  \n\nthe fact that einstein's theory, largely concocted out of the blue from basic principles and logical reasoning, has stood the test of time for so many years is a testament to the genius of the man's work.\n\nhere are some links to learn about phase velocity, group velocity and the speed of light:\nhttp://en.wikipedia.org/wiki/Group_velocity\nhttp://physicsweb.org/articles/news/4/7/8/1
349427
no, anything that travels close to the speed of light becomes more massive as it goes faster, and would actually become infinitely massive at the speed of light. this means it would take an increasing amount of energy just to get close, and an infinite amount to reach that speed. the only reason light can reach that speed is because it is made of photons which have no mass. even a tiny particle like an electron can never actually reach the speed of light.\n\nHowever, faster than light travel may be possible by warping space-time itself, using phenomena like wormholes or even black holes.
61379
MitchHellman has the best answer!\n\nBut just cuz....a tachyon (theroetical particle) cannot travel *slower* than light. An effect called phase velocity (wave mechanics) can also travel faster than light, but these things are not real in our normal sense of the word. But these are some things people do discuss which have this property.\n\nOtherwise.......no.\n\nlol
143269
As you approach the speed of light, your mass approached infinity... As your mass approaches infinity, it takes more force for you to accelerate... Therefore, I don't think it is possible for you to acchieve the speed of light...
657426
Well the sad truth is YOU CAN'T...in fact you can't even travel at one times the speed of light. Einstein covered this about 100 years ago. Anything that has mass cannot achieve the speed of light for a couple of different reasons. Trust me on this.
644825
According to Special Relativity Theory, when you are transporting a mass at a speed near lightspeed, the energy needed to increase your speed rises to infinity. We can't provide the system with enough energy to reach the light of speed.\n\nEnergy, though, can travel at the speed of light because it has no mass. If we could transform a mass in energy (remember: E = m c^2) and re-create it at destination, travelling at lightspeed would be possible.\n\nBut, as Dark Helmet said, speed of light is too slow. We need ludicrous speed!
366136
Not really - As it would travel at the speed of light (or the lack of) - but there would be a delay of a few picoseconds.....
297054
heres the info:\n\nNobody has ever managed to ride a beam of light, although Einstein in his youth imagined what it might be like to do so. Such thinking eventually lead to the special theory of relativity. Although it is still impossible for anyone to travel on a light ray, physicists have managed to stop a laser beam in its tracks! This amazing result builds on earlier work by a research group led by Lene Hau in which light was slowed to 38 miles per hour.\n     Light in a medium travels somewhat slower than 300,000 kilometers per second, its speed in a vacuum. This effect, known as refraction, is responsible for the bending of light in passing from one medium to another. In an ultracold gas of sodium atoms, the index of fraction varies significantly with the frequency of light. The gas is normally opaque, but when the sodium atoms are bathed with secondary "controlling" laser light of a particular frequency, the medium becomes transparent and light can pass through it. Due to the varying index of refraction, a primary laser pulse slows down when it enters the gas. It also becomes greatly compressed. A pulse with a length of one kilometer gets squeezed into a tiny unit one one-thousandth of a meter in length. When the light pulse exits the region of sodium atoms, it expands back to its original length zooming off at 300,000 kilometers per second again. \n     To bring the light to a standstill, Dr. Hau and her co-workers turn off the secondary controlling laser light after the impinging laser beam has entered the ultra cold sample. The medium becomes opaque. One would think that the laser pulse would be absorbed by the sodium atoms. Instead, the information about the light wave is encoded in the atoms. When the controlling laser light is turned back on, the atoms reconstruct the laser beam. It continues its propagation though medium and then out the sample. If the time during which the beam is halted is not too long, the shape of the reconstructed beam coincides to a high degree with the original shape.\n     Imagine a train one kilometer in length consisting of thousands of cars traveling at 300,000 kilometers per second. Suddenly, the track becomes rough, causing the front engine and subsequent cars to come to a screeching slowdown. With the train now moving at 38 miles per hour, the cars pile up and are crushed to the size of an ant. Then a magician snaps her finger and the train disappears but leaves an imprint on the dirt between the tracks. With a second snap of the finger, the imprint vanishes while the ant-sized train reappears and moves forward at 38 miles per hour again. Then the train encounters smooth track. The engine speeds off at 300,000 kilometers per second, and as subsequent cars enter the smooth track region, they too rapidly speed off so that the entire accordion-like structure unfolds. Remarkably, little damage to the train occurs.\n     "Impossible!" You say. Well, in the case of a train, it is impossible because the deformation of metal is an irreversible process. But light is more accommodating and can be stretched or compressed more readily. Still, Dr. Hau's team has done what seems to be magical. Why isn't the light absorbed and lost? How can the atomic information reconstruct the beam? Why isn't the beam greatly distorted when it leaves the sample? The answers to these questions reside in the miracles of quantum mechanics, the dynamics that control the microscopic world of atoms and their interactions with light.\n     A major technological breakthrough has occurred. If low cost means are found to manipulate light in the above manner, then computers and communications will be revolutionized. One can imagine using light instead of electrons to perform computational processes. Such photonic machines would calculate at many times the rate of current computers.
214684
No massive object can move at the speed of light, so the question is ill-posed. Sorry.\n\nAs a physicist, please let me give you a little advice: don't loose your time with this nonsense, try instead to focus on the mathematics of the relativity theory, that's the way to understand it. The rest is pseudo-science.
689820
Neither you, nor the train, could ever travel at the speed of light since both of you have some non-zero rest mass.\nIn order to accelerate something with a non-Zero rest mass, an infinite amount of energy would be required....and in the whole universe, there is not an infinite amount of energy.\n\nBut lets say you were traveling just under the speed of light...at 99.99999999999999% of c and you began to run toward the front of the train, \nyou would still NOT be traveling at or above the speed of light (as seen from an outside, "stationary" observer) since at relativistic speeds such as this, velocities do not add in the normal Galilean way, you would still be traveling slower than the speed of light.
1065439
The speed of light - it can't go any faster!\nThere will be a distortion however, called blue shift.\nThe perceived (by a stationary observer) frequency of the light would increase, and the wavelength would decrease, so that the velocity is constant v=fλ\nThe distortion would be infinitesimal 30 parts in 186000*60*60.\n\nSound would experience a similar distortion, so that if a vehicle sounds its horn as it drives past, there is a perceived frequency change in the sound.  This is called the Doppler Effect - there is a link at the bottom of the blue shift link... (see also red shift)
265616
The two key elements in this question are that the speed of the spacecraft is constant, and that you are at rest relative to the spacecraft.  In this situation, you will observe the beam of light moving forward and hitting the object just the same as if you were sitting in your living room.  This is in accordance with Einstein's Special Theory of Relativity.\n\nHowever, if the spacecraft were accelerating instead of moving at a constant speed, the same might not be true. As long as the spacecraft continues to accelerate, even at speeds below the speed of light, it is possible to set up a scenario in which the spaceship stays ahead of the beam of light forever!  This is in accordance with Einstein's General Theory of Relativity, which considers the effects of acceleration and gravity on light.
163148
Nothing happens, the car lights will travel at the speed of light in comparasion to the car. This doesn`t mean that the lights will travel twice as fast, you cannot add this velocities without taking into account Lorentz equations.\n\nIs it deja-vou or is it the third time this question has been asked?
42712
It isn't possible speed wise, the closer you get to the speed of light, the larger your mass, until it becomes infinitely large - there is not enough power in the universe to acellerate you that fast.  The only way to travel faster than light is to take a shortcut, find a way from point a to point b that doesn't involve a direct course - like a wormhole or some other type of spacial rupture. If you think of 3D space as a sheet of paper, light can only travel over the surface - if you fold the paper, you get to the other side quicker by going right through the paper. Technically, you dont go as fast as light (which would have to travel the length of the 'paper'), but you get to your destination before light going the normal space-path would, so in that respect you do go faster than light.
470012
A couple of years ago there was a study that said that the speed of light is not a constant. I need to look it up and see if I can find it. Now I'm wondering what the reason was behind that claim.\n\nYep, I found it:\nhttp://www.newscientist.com/article.ns?id=dn6092
1061558
Moving faster than light isn't really the real issue for space travel as traveling AT the speed of light solves all the distance problems(unless you are interested in time travel!). Of course that in itself is a big challenge. If one could demass the vehicle then surely one could achieve the speed of light!!! Afterall photons do travel at this speed.\nBut we would do very well even with speeds like .99999c because time dilation will reduce the time required drastically. Have the science, just need the technology!
64217
to answer your question it is possible to go faster the the speed of light. The speed of light is 186,000 miles per second.\n\nIf zooming beyond the local speed limit is punishable by law, then some scientists may have a gargantuan speeding ticket to pay. \n\nIn a controversial experiment reported in this weeks journal Nature, scientists at the NEC Research Institute in Princeton, New Jersey claim to have broken the ultimate speed limit -- the speed of light. Though hotly contested, some say this achievement could dramatically increase the speeds at which we can send and receive information. \n\nTaught in physics classes the world over, Albert Einsteins theory of special relativity holds that no object or information can move faster than the speed of light in a vacuum, or 186,000 miles (300,000 kilometers) per second. But NECs Lijun Wang says he created an experiment in which a light beam raced through a gas-filled chamber so quickly, it exceeded the speed of light by a factor of 300. Whats more, the light pulse appears to have left the confines of the chamber before it even entered a seemingly impossible occurrence according to theories of causality, which predict that causes must always precede their effects. \n\n"It sounds crazy, but this can actually occur," said Raymond Chiao, a physicist at the University of California at Berkeley. Chiao, one of a group of researchers who have been working to break the speed-of-light limit, explained that although a common object such as a baseball could never be flung faster than the speed of light, pulses of energy with certain complex properties have been known to bend the rules. \n\n\n\n"It sounds crazy, but it actually can occur." \n\n\n\n\nIn fact, several recent experiments, including one done by Chiao earlier this year, have pointed to energy pulses zooming faster than light speed. Yet each of these experiments has been encumbered by severe limitations on measurement or observation of the energy pulses. In contrast, this latest experiment is being touted by some as the most dramatic example yet of light breaking its own speed barrier. \n\n"The effects are much larger and more spectacular" than previous observations, said Chiao. \n\nIn Wangs experiment, a pulse of light passed through a small chamber filled with atoms of elemental cesium. A light beam traveling through such a medium has two different velocities a velocity for the individual light waves in the beam and a group velocity for the entire beam. Oddly, some light waves in the beam can actually travel backward for miniscule amounts of time, creating a sort of "tail" behind forward-moving waves. As such, a light wave and its tail can leave the gas cavity at different times, creating the effect that the light beam has left the cavity before its even entered. \n\nConfused? Youre not alone. In fact, even scientists who are familiar with this area of study are unsure about the details of Wangs experiment. And many scientists said the experiments results are still open to interpretation. \n\nWilliam Happer, a physicist at Princeton University argued that several specific problems exist with the experiment, including the fact that pulses get distorted when passed through any media other than a vacuum, or empty space. In addition, he said Wang and his colleagues performed the experiment in a way that doesnt tell the whole story, and that it can be interpreted incorrectly. "This is anything but dramatic," said Happer. "If you look at the data, theres essentially no evidence that [the beam] is going faster than the speed of light." \n\nWhats more, most scientists agree that even if such a beam can be proved speedier than light, it would probably not be able to carry any information. Such a feat could conceivably allow data to be sent back in time, thus violating laws of causality and sending quantum physics into disrepair. \n\nOthers are more optimistic as to the possible