I think the bending of light in gravitational field is caused by the change in speed ....is it correct.
127694
No, the speed of light in vacuum is constant everywhere.\nLight follows the path of minimum energy (geodesics) in gravitational fields, which are bent around the masses.\n\nThe amount of bending at the surface of the sun is of the order of arc seconds. However close to a black hole the bending is so strong, that the light path bends around and around the hole, never to escape.
5754
There is this wonderful little thing called a "Rest mass", and should something have an imaginary rest mass (i.e. tachyons) its lowest speed possible is the speed of light.  However, this is one wacky hypothetical construct that has no proof nor anything to disprove it.\n\nAlso, the spacetime continuum itself can move faster than the speed of light; it has happened before, less than a second after the big bang.  This wonderful thing called inflation happened, and spacetime grew obscenely fast.  This is also why spacetime is mostly flat.
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.
581054
There are two types of particle in the universe. Those with a rest mass (ie a mass when they are stationary) and those with no rest mass. Only zero rest mass particles can travel at the speed of light.\n\nMeasurements have shown that the speed of light is the same however fast you are moving. This couterintuitive result is the basis for special relativity. It is fairly straightforward to show from this measurement that accelerating a particle with non zero rest mass close to the speed of light does not simply add to its energy but increases its mass. An infinite amount of energy would be needed to accelerate a particle with non-zero rest mass to the speed of light. This effect too can be measured in a lab.\n\nThe red shift does not have its origins in changes in the speed of light at all - in fact it relies on the speed of light being the same for all wavelengths of light. It is in effect the doppler effect for light - the same thing that makes the frequency of a passing car drop as it recedes.\n\nAnd it is perfectly possible - not even that difficult - to do measurements on the speed of light accurate to 8 or 9 decimal places.
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.
261777
Yes gravity does have an effect on light. But your example does not show it. Gravity on earth is not strong enough to have a NOTICABLE effect of light but a black hole has enough gravity to bend light into it. \n\nYou just notice light on the ground because it is a surface for it to reflect off.
280701
No. First, matter can't get to the speed of light because it would be infinitly massive and would take an infinite amount of energy to do it so the question starts out with a bad premiss.\n\nHowever, if a plane were traveling at half the speed of light and turned on it's headlights, they would be going the speed of light to him and the speed of light for someone on the ground watching. You see the speed of light is constant for all observers in a non-Newtonian reference frame.
350761
The variations in the passing of time can only result from gravitational effects or relativistic effects. \n\nFor relativistic effects to be aparent, you have to be travelling at a speed comparable to the speed of light. Even then, there must be different velocities involved. Therefore night/day should not make a difference, unless he is referring to the fact that you are moving around in the day (thus, relatively time passes slower for you with respect to your surroundings) and stationary in the night. However, this does not make a noticable difference at all!\n\nAs for gravity, it is not something I know very well, and don't think it is really easy to explain, but it might have something to do with being farther away from the sun (by a length of earth's diameter) during the night. Again, this should not affect the passing of time almost at all.\n\nI suppose he really was trying to make a joke of some kind, maybe based on the fact that people go to sleep after much later than nightfall and wake up early with the first lights. Also, the twilight times are usually considered day rather than night.\n\nOR: He might be referring to the movement of the stars in the night sky and the movement of the sun during daytime.\n\nNevertheless, I think it's a pretty weird question, please message me if you learn the real answer.
392776
Hi,\n\nFirst think about space as a big sheet of saran wrap. Then imagine that mass distorts the sheet, causing wells, or dents in it. now imagine that the photons need to travel along the saran wrap (i.e. traveling through space) and it makes sense that they would seem to change directions with respect to gravity. \n\nThat is a gross oversimplification, but I think that the analogy is roughly correct.\n\nHope that helps, \nMatt
359231
The speed of light is Warp 1\n\n2xspeed of ;ight is warp 2\n\nand so on and so forth.
104855
Light speed is constant but can be warped by objects or black holes gravity. Science can only assume on such matters by use of mathimatical functions. Unless of course someone could travel to a black hole and make it back to tell the story, hundreds of years from the time they left.
463144
http://en.wikipedia.org/wiki/Gravitational_time_dilation\nall i know of is high speed and gravity distort time. like the gravity of the earth creates a small distortion around it.
663841
Well, actually, your theory is very similar to that of the Theory of Relativity, or something. If you slowed down time by moving faster, the objects would literally gain weight. (Fat people, plz do not go on space missions...) And once you were travelling at the speed of light, you would have infinite weight. (But of course, your MASS would still be the same. So fat people should let out a big breath.) I'm not sure exactly which theory this is...
8816
You're right, it is due to the speed they are traveling.  Velocity distorts time by the factor: t'=t/sqrt(1-v^2/c^2) where t' is the time that passes for a stationary observer, t is the time that passes for the object moving at the high velocities, c is the speed of light, and v is the velocity the object is moving.  \n\nThis effect is basically negligable unless the object is moving close to the speed of light, but the orbiting satellite is moving pretty fast for a very long time, and so even though it's traveling at a very small velocity relative to the speed of light, it still builds up a little and creates a small distortion of time that is barely noticeable.  For example, let's say the satellite is traveling at 8,000 m/s for 5 years.  if you do the math, there are 157680000 seconds in 5 years.  The speed of light is 299792458m/s.  Now lets see how much this effects time.   That number will be t', since it's how much time passes on earth for 5 years.  Now let's see about on the satellite:\n157680000=t/sqrt(1-(8000^2/299792458^2)  solving for t, (must have fancy calculator with a LOT of places) we get t= 157679999.88772s  subtracting this from the original time, the clock is behind by .11228 of a second.  \n\nTime moved slower for the satellite, but since the velocity is so small compared to the speed of light, the amount that is different is so insignificant, that you wouldn't be able to see the difference through a telescope.  However, they want the clocks to be perfectly calibrated and exact, so they do that to make up for this small effect because it would build up more and more as time went on, and the faster the satellite is moving, the more time is distorted.
437498
It is exactly that question that inspired Einstein to formulate his theory that nothing can ever travel faster than light. I am not saying the Einstein had a goal to make a theory saying nothing can travel faster than light. I am saying that the question made him think about how to explain what would happen in such a case and then the math lead him to a theory of motion in general which says nothing can travel faster than light.
99372
Relative motion between objects was not new to Newton and his contemporary scientists.\n\nEvery experimental result proved and confirmed again and again Newton’s laws of motion even in the frames of reference moving relative to each other.\n\nLatter with the improvement in measuring technology and particles moving nearly equal to the velocity of light, their behavior contradicted Newton’s laws.\n\nEinstein with a firm belief that any physical law (including Newton's law) must be the same in any reference frame moving relative to each other postulated that speed of light is independent of the source of light.\n\nThis explained every experimental result well and obeyed Newton’s laws.\n\nThe only difference is that  the basic quantities mass , length and time which during Newton’s time was thought of absolute in the sense that  they will not change with the velocity of the frame in which they are , is now considered to vary with the speed of the reference frame, and the velocity of light is independent of the motion of the source.
52814
well its supposed to be constant no matter where it is. but think about this: black holes are said to be black because the light is not fast enough to escape the force of gravity. like on earth the acceleration of that force is 9.81 m/s/s so if you went faster than that then you could leave earth. so the gravity in black holes is greater than the speed of light. now that means that the light "falls" back in. but gravity only acts on things with mass so this means light has mass, which would make sense. which means it must be very slightly affected by lesser gravity as well. so if it is on the outskirts of the universe where there is less gravity the velocity should be slightly different.