couple of q's\n\nif you are moving forward at any speed and your turn on a laser, is the light from the laser moving faster than the speed of light?\n\nIf you are traveling at close to the speed of light and you throw a baseball forward, does the baseball travel faster than the speed of light?\n\nif you put two lasers together faced at the wall; one say a 1 inch and the the other 5 inches from the wall. if you could turn them on at the same time would the light from the closer laser hit the wall earlier than the farther laser?\n\nI heard that it takes 25 pounds of fuel to accelerate 1 pound of mass to the speed of light. if this is true what is the maximum speed physically attainable if a vehicle was nearly 100 percent fuel and the fuel was entirely used up at that speed?
132035
Think of this\nwhen it comes to space the constant thing is the speed of light. Speed is the TIME it takes something to travel set distance.\nAt the moment we are moving through space. An hour ago we were a few hundred thousand miles from where we are now. If you were sitting still where we were a few hous ago, you would be slightly older than us.\nThis is because the constant thing in space is the speed of light. As we get closer to the speed of light either time gets smaller or distance gets smaller.\n\nIf this does not seem possible, just think of a unit of time as one vibration of an atom. Go faster, atoms vibrates slower, your time is therefore slower than some one who is still. (this is a metaphor people can comprehend, not quantum fact)\n\nSo question 1. Light is travelling at speed of light. Time and space do whatever they have to do to accomodate this.\n\nQ2 No, see Q1. You also would no be strong enough to throw the ball\n\nQ3. The closer one gets there first. just like anything else.\n\nQ4. What fuel? It would accelerate exponentially as the mass decreased. Top speed comes dowon to rates of accelerate, motor efficiency, drag, ect. Then as you got really fast your mass increases. Mass increases (again I'll use a compehendable metaphor and not quantum physics) because distance decreases, things are closer together, denser, heavier. Then your rate of fuel consumption would increase exponetially and your velocity would barely change. Then you'd run out of fuel
151413
The first answerer is right about the mass increase.  As a mass approaches the speed of light, one of the effects is that the more energy you provide it in order to increase its velocity, the more the mass increases, according to Einstein's famous formula E=mc^2.\n\nThe speed of light is the absolute limit for velocity.  A mass can approach closer and closer to this speed, but can never surpass it.  So, to answer your question, mankind can and likely will build spaceships which can go significantly faster than the present-day ones can, but we will never be able to travel at the speed of light.
283325
There is a big difference between predictions that the speed of sound could not be broken and that the speed of light cannot. It was always known that *some* things can go faster than sound. Bullets for example. The question was whether we would have the technology to get people to that speed.\n\nThe speed of light is very different since we haven't seen *anything* go faster than light in a vacuum. Nothing. Ever. Furthermore, the predictions of special relativity have been verified in particle accelerators when the particles are going to within a hundred thousandth of the speed of light.\n\nAs an example, at Fermilab protons are accelerated to energies of 2TeV. This is over 2000 times the rest mass of those protons. To accelerate something the mass of a *gram* to an equivalent speed would take about the energy of the largest hydrogen bomb ever exploded. This amount of energy would be needed for each gram to get to that speed, so multiply it by 75000 for a medium sized human. And that doesn't count the spaceship they would have to travel in!\n\nNow, this is how much energy is needed to get to speed we *know* about. To go faster would require even more. Unfortunately, we have never seen a wormhole of any type. But the predictions are that the energy requirements would be even more prohibitive than what I just described.
504475
If you apply a force to move an object, you produces work, and this work is equal to the kinecti energy change.\n\nThe speed of light is not force!!!!
592613
There may be objects (tachyons) that move faster than light, up to perhaps infinite speeds.\nHowever, nothing already slower than light can accelerate to or beyond the speed of light.
328776
The speed of light is the upper limit of speed in our space-time universe. Nothing here can be faster. And no car or any other macroscopic object can be equal to the speed of light. But the question is a thought experiment, hence, a good one indeed. Questions like this were raised by Einstein and Relativity became part of modern physical theory.\n\nSince the speed of light is an upper limit, the light from the headlamp of the relativistic car cannot be faster than the car. You won't see them in front.
565097
The key point to this whole question is if you could travel faster than light.  Since at our present knowledge of physics says no, and our current tech is not able to get anywhere remotely near the speed of light let alone faster than it, we will assume this hypothetical question implies these two things don't matter.\n\nIf so, then yes you could see into the past if you had an adequate viewing device which could discern the light you would receive at the end of your journey--light which you left behind by going faster than it.  But to see exaclty the number of years in the past as the light year distance you travelled, you woould have to move instantaneously.  If you had any non-relativistic travel time, you would have to consider time of your journey to determine how far in past you were seeing.  If you travelled 1.1 times the speed of light, you would only get to see .1*light year distance in years past.
424714
You misunderstand Einstein's Theory of Special Relativity. It doesn't say that you can't have something move faster than the speed of light. Only "information" can NOT move faster than the speed of light. By information, I mean any "signal", like electromagnetic waves (which includes light, radio waves, etc. etc.). Any material object within the Universe are also restricted by Special Relativity, since material objects also carry "information".\n\nFor the Universe or the fabric of spacetime to be expanding faster than the speed of light is NOT a violation of Special Relativity, and the Universe will not be moving backwards in time.\n\n--------------------------------------------------------\n\nEdit - Ok, here let me clarify why I said that Special Relativity (SR) does NOT apply to the expansion of the Universe:\n\nVelocity of something depends on which definition of distance we use. So, if we assume that the distance of an object at time t is the distance from our position at time t to the object's position at time t measured by a set of observers moving with the expansion of the Universe, and all making their observations when they see the Universe as having age t, then the velocity (change in D per change in t) can definitely be larger than the speed of light. This is not a contradiction of special relativity because this "distance" is not the same as the spatial distance used in SR, and the age of the Universe is not the same as the time used in SR.\n\nIn the special case of the "empty Universe", where one can show the model in both special relativistic and cosmological coordinates, the velocity defined by change in cosmological distance per unit cosmic time is given by v = c ln(1+z), where z is the redshift, which clearly goes to infinity as the redshift goes to infinity, and is larger than c for z > 1.718.\n\nFor the "critical density Universe", this velocity is given by v = 2c[1-(1/sqrt(1+z))], which is larger than c for z > 3. \n\nFor the "concordance model" based on CMB data and the acceleration of the expansion measured using supernovae, a flat Universe with Omega = 0.27 (this would be our Universe), the velocity is greater than c for z > 1.407\n\nAll this just means that for any expanding universe, there will be a value of z (i.e., redshift or cosmological distance) that will give the appearance of galaxies moving at velocities greater than c.
677105
Light always travels at the same speed in a vacuum, the speed changes ever so slightly when it has to go through a different medium (water e.g.) but its so fast to begin with you wouldn't really notice it. 300,000 kilometers per second is beyond human comprehension, I mean you can only imagine how fast that is, you can't experience it or 'know' it.
44857
I too would be veeerrrrry interested in seeing some evidence for this claim from a non-creationist source. I keep an eye out for this sort of thing out professional as well as personal interest and I can't recall seeing anything like it.\n\nRoger are you absolutely certan that you haven't misundertsood the phase velocity experiments of Wang? They were done around that time (published 2000 IIRC). But they never shattered the speed of light or anything like that, no  did Wang et al ever make such a claim.\n\nTo help you out Roger, folow the link below? Is that what you arehtinkng of? If so you have misunderstood the results entirely.\n\n" Wang et al. (2000), who produced a laser pulse in atomic cesium gas with a group velocity of 310+/- 5 C. In each case, the observed superluminal propagation is not at odds with causality, and is instead a consequence of classical interference between its constituent frequency components in a region of anomalous dispersion (Wang et al. 2000)."\n\nIOW the speed of light wasn't exceeded by a particle, massless or not. It was the speed of the frequency change wihtin the medium that was 300 times faster than light. Perhaps the easiest way for a layman to understand this is to imagine one of those Newton's Cradle's toys. (see link 2). \n\nWhen you let go of one ball the motion is tranferred through the two intervening balls to the other end, causing that ball to fly up. That motion is is transmitted at near enough the speed of sound. IOW when the dropped ball hits the suspended balls the motion is passed along at the speed of sound. \n\nBut, and this is important, the ball itself wasn't travelling at the speed of sound. Nor did the ball on the end fly out at Mach 1 just because the motion was tranferred at MAch 1. The motion of the drooped ball was transferred at Mach 1, but at no stage was the ball or anyhting else actually travelling at Mach 1.\n\nWang's experiments did approximately the same thing using photons rather than metal balls. By some very clever work they managed to induce a phase change within the Cesium medium. In essence the Cesium atoms became the middle balls in newtons cradle. When light  hit an atom on one side it caused a phase change that was then passed on to the next atom, then the next and so forth, all at 300*C. But it was the phase change that was moving at that speed, not photons, not even electrons, just a phase change.
137869
In the relativistic limit (i.e. speeds near the speed of light [here denoted "c"]) velocities are not additive in the normal sense.  In particular one must use the relativistic velocity addition rule given by:\n\nv_1 + v_2 / { 1 + (v_1 * v_2 / c^2 ) }\n\nWhere v_1 and v_2 are the speeds of the moving observers.  Notice that when v_1 and v_2 are both siginificantly less than c this reduces to \n\nv_1 + v2, which is what you expect from the everyday world.\n\nIf you plug in .95 c for v_1 and v_2 you obtain that the apparent velocity of the observers to each other is given by:\n\n.998685939553 c or 99.865% of the speed of light.\n\nWhich is how fast they will appear to approach each other from each other's perspective.
416276
In theory, yes.  Because the light particles that were traveling slower than you would have been slower.  Very good question.  However, speeding past the speed of light would mean the fundamentals of E = Mc^2, would cease to make sense.
558222
It would pass inbetween the gaps in the fan.  Nothing moves faster than the speed of light.  So saying a fan goes the speed of light, well ok, but light will still move faster than the fan.  It's like holding a regular fan infront of a light souce.  You get sort of a flickery strobelight affect on the far wall.
442011
I'm stepping waaaayy out on a limb because I deal with radio frequencies but, \n\nif it takes .5 ns to process from memory, that leaves 1.5 ns for pulse to travel there and back.  \n.75 ns to travel to.\n.75 ns to travel from.\n\nAssuming velocity times are in free space (vacuum), which your statement doesn't say, then:\n\nd=c*t\n\n(c) 299,792,458 km/s  x( t) .75  = \n\nFree Space = .2248443435 m/ns (.225 m/ns)(22.5cm/ns)\n\nIf you take into account the velocity factor of silicon \n(said to reduce the velocity of light by a factor of 200 in first of article source, and 300 in second article of source)\n\nI think it's next to impossible to come up with a figure other than in a perfect medium, until scientists decide a consensus of opinion on the velicity factor of silicon.\n\nClose?\nI tried.
4945
It's true that the speed of light is constant no matter what speed at which you or the source is moving.  This is a fundamental postulate of relativity, and there is no explination.  It's just accepted because our experiments indicate that it is true.  You used the formula "lights speed + X = actual speed"  this type of velocity addition is called "Galilean".  It turns out that speeds don't actually add that way.  Far out.\n\nWhere is the rest of the energy? Good question.  The frequency of the light you observe from the sun DOES depend on how fast you and it are moving.  The energy of each photon is given by E = hf, where f is the frequency of light.
580964
The example of each person going faster than the previous assumes a consistent additive nature of speed which unfortunately falls apart (shown by experimentation) as your speed approaches the speed of light.\n\nSpeed is not absolute in the sense that there isn't a universal stationary reference point.  If there were, then the example will apply.  According to experiments, however, something travelling away from you at light speed will do so regardless of whichever direction you happen to be moving.  This is not something to reason about (nobody arbitrarily made up this rule so that philosophers can find loopholes around); it's just what's been observed so far.\n\nThe Wikipedia article at http://en.wikipedia.org/wiki/Speed_of_light explains it a lot better than I can.  Jump to the section "Constant velocity from all reference frames" for the discussion applicable to this example of yours.\n\nHowever, an article at http://science.howstuffworks.com/news-item6.htm suggests that at least two experiments (pending validation) may have found exceptions?
404852
Good question, shows you are thinking.\n\nPresent technology contends that only light, pure energy, can go as fast as the speed of light.\n\nTaking that theory to heart, if a space ship actually achieved the speed of light it would turn into pure energy (light) and cease to exist as a solid object. The test pilot would theoretically commit suicide in an attempt to learn if it was possible.