Me and a fellow student theorists have been arguing recently.\nThe scernio is as follows: \nSoppose a man is dancing on the sun.  Due to the vast distence between earth and Sol, the image of the dancing man is constantly being relayed to your brain 8 minutes after realtime, or when it happens.\nNow soppose you jump in your amazing superspaceship and fly towards the sun at the speed of light.\nMy friend thinks that the image will speed up as you approach it because it won't take as l;ong to reach you.\nI argue that the image will not speed up, but rather will just approach realtime, seeing as it is eight minutes behind.  It seems like as you approach it the light that reflects will take less time to reach you and hence you will see it closer to real time, but since you are already travelling at light speed yourself, the difference it takes to reach your eyes will not be noticed because you r traveling towards it at the speed of light and so it will reach realtime as you reach the sun.  HELP!
125717
OK, first lets say that the rocket moves at a constant speed of 80% of the speed of light. Working with an accelerating rocket would be hard and .8 is a convienent number.\n\nso we have beta=.8 \ngamma=1/sqrt(1-.8^2)=5/3 and \nbeta*gamma= 4/3\n\nIf you dont understand this, look up lorentz transform in your textbook.\n\nWe will use a two dimensional unprimed coordinate system with distance in light minutes on the x axis and time in minutes on the y axis. The sun is located at x=0 and the earth at x=8 light minutes. Draw 45 degree lines, representing light rays, intersecting the x=0 axis at one minute intervals. Draw a vertical line at x=8 representing the earth. The light ray starting at (0,-8) intersects the earth at (8,0) meaning this is the event where people on earth observe what happened on the sun 8 minutes ago. We will call this event A.\n\nDraw a line with a slope -1/.8 intersecting A. This is the path of the spaceship. It will reach the sun at the time 10 minutes.\n\nNow we will calculate the cooridinates of event A as seen by the spaceship approaching the sun. We have\n\nA'= [gamma       beta*gamma]  [8]\n.......[beta*gamma  gamma     ]  [0]\n\nA'= 1/3 [5 4] [8] =  [13.3]\n.............[4 5] [0]  ... [10.6]\n\n(hopefully the ... makes the matricies line up)\nSo the guy in the spaceship NAMES this point 13.3 light minutes and 10.6 minutes.\n\n\nNow lets look at where the line of the light ray from (0,0) intersects the path of the spaceship. Using trig we get (4.44,4.44). Call this point B. This is where the guy in the spaceship observes what happened on the sun at time 0.\n\nNow lets lorentz transform this point\nB'= 1/3 [5 4] [4.44]  = [13.3]\n.............[4 5] [4.44] ...   [13.3]\n\nnotice that the x' coordinate is 13.3 for both point A' and B'. This is because from the perspective of the guy in the ship, he has not moved. The elapsed time for the guy in the ship between A' and B' is 13.3-10.6 = 2.7 minutes.\n\nSo, he has seen 8 minutes worth of dancing in just 2.7 minutes. The image has speeded up.\n  \n* This is the correct method for solving this problem, but you might want to double check my math.
285974
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 ...
226835
EINSTIEN once said that he can't travel in time but one can SEE THE FUTURE . he said that if such a lense can be made that  it can allow us to see the edge of the EARTH in the prescence of  a   powerful laser the affect shall be like: one endsup seeing himself and in a totaly other situation and thus he proposed a theory on this concept of time travel\n\nbut we have to  just cross the speed of light ....... to have this another theory in action\n         this theory states that one can travel in time when he travels the  7times faster speed of light, and   it is surely going to take a lot of time to prove or disprove this theory ................as EINSTEIN could never prove the previous one!!!!!!!!!!!!!!!!!!!
600443
The most recent research that I've seen was shown on the TV program "Horizon" here a few years ago.  The research suggested that under certain conditions (somehow linked with Einstein's cosmological constant) the speed of light could possibly change.\n\nHowever, for the time being at least we can easily assume that the speed of light is a constant.  The last I heard was that the research they were doing on the speed of light has was inconclusive, so it may take a while longer before we really know if it can change or not.
109523
You can't reach the speed of light in any conventional way, but you can get as close as you want, provided you can keep applying acceleration.  \n\nThe best way to do a thought experiment of time dilation for special relativity (special relativity being the case in which you consider high velocities, general relativity just applies this same model to all spacetime trajectories with the observation that gravity is indistinguishable form a physical acceleration) is to consider the case of a "light clock".  \n\nFor a light clock, you have a laser pulse generator, a mirror at some distance, and a pulse counter next to the laser.  Everytime a pulse is recieved at the counter, another pulse is sent from the laser, and so you have a clock that "ticks" at a rate determined by twice the distance from the laser to the mirror.  So, what happens when you move this clock?  If the clock is arranged such that the pulse bounces back and forth perpendicular to the direction of travel, it's easier to get the basic idea.  \n\nThe speed of light is always constant, but as the clock moves at higher and higher speeds, from the perspective of a stationary observer the total distance traveled by the light increases, since now it's going diagonal.   But, to a person traveling along with the clock, it doesn't appear to travel any greater distance.  \n\nIt's something like a person standing in a train car or bus tossing a ball up and down.  While the ball is up in the air, it travels horizontally by the distance the bus has moved while it's been up in the air, so the total distance traveled by the ball is much longer if the bus is moving rapidly instead of stationary.  For normal speeds, the Gallilean transforms are sufficiently accurate, so a stationary observer and the person tossing the ball can agree how fast it's moving in each axis, and how far it moves, just by adding the horizontal velocity of the bus to the vertical velocity the ball is tossed with, and come up with the same wider parabola for higher speeds and narrow parabola for low speeds, or stationary cases.  \n\nBut, light has an interesting property...  it must remain at the same velocity for all observers no matter what their speed relative to the light.  So, in the case of a ball, we can simply say that it's moving faster than it looks to the person on the bus with it, because there's the added background horizontal velocity.  If you add the vertical and horizontal velocity vectors, the sum is longer than just the vertical velocity.  \n\nBut, in truth, how can you know if you're moving at a constant velocity?  There are no pseudoforces of acceleration if you're moving at a constant velocity, but if light behaved oddly by traveling faster in one direction that the other, you would be able to tell if there was a fixed frame of reference outside of your motion, and this would allow you to determine a fixed location relative to the universe as a whole, and even determine where the center of the universe is.  But it doesn't have a center, or all points are equally the center, depending on how you want to look at it, so there can't be any way to tell if you're moving at a constant velocity, and so light must travel at the same speed in any direction when viewed by any set of observers, no matter what their relative velocities are.    Not surprisingly, we find this also comes out from Maxwell's equations describing the propagation of light, the velocity winds up being proportional to one over the square root of the product of the electrostatic permittivity and the magnetic permeability of empty space, a number which is absolute and gives no preference for directions or relative motions.  This isn't surprising since, like I said, it's a necessary condition for a centerless universe.    \n\nSo, the speed of light must remain absolute, but something has to give.  Since the light clock is ticking slower becaus
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.
415075
Your conclusion is interesting, but Einstein theory proves that we can travel forward in time if we travel at the speed of light. No one can go back in time, imagine. a guy from the future gives us a history book from, let's say, 2100, and we can know the future of our time, and change it at will. So, if someone does that, he creates 2 differents futures... It's all very complicated....\nI say that the UFO are UFO. We don't know who they are, where they come from, and if they even exist. I think that they visited earth before. \nHere's some explanations:\nThe pyramids of Egypt, even with our technology now, it'll be nearly impossible to build them. do you really think that they could have built it?4000 years ago? i think they got help from aliens...\nHow come there are pyramids in Egypt, and Mexico? Three possiblities: or the aliens went to Mexico too, or maybe some egypyians went to Mexico, or that it's just coincidence. \nIt's hard to prove that aliens exist, but i;m nearly sure they do. Can we really be alone in the universe? or do we want to be alone in the dark?
535592
You've lost the point of the equation.  Squaring the speed of light will give you the energy released, not an enhanced speed of light.
282839
As per Stepehen Hawkings "brief History of Time", you can't see the light if you are moving with the velocity of light. Because there is no apparant change between the object and the source.\n\nYou forgot another intersting thing... if u are travelling with  a velocity of light, your mass will be infinity and your age will not change! (unbeleivable !)\n\ni hope this answer deserves 10 extra credits! :-)
92036
His definition is a little odd, and does not seem to follow from his example (which is more about motion than position on the earth).  Technically, his motion relative to stationary students would make time pass at a different rate according to all that Einstein stuff (though there's no way he could ever notice the tiny difference).  But that would be true without any reference to the earth and the sun.  Is he trying to make a different point -- that his days would be longer because the sun would set later for him because he is walking toward the west where the sun sets?  If so, he's right that his days (defined as revolving around the Earth's axis) would be longer, but that would not mean time was moving at a different speed for him; it would only mean that the sun would set a little later from his visual perspective -- just like you can gain or lose hours when you cross time zones in an airplane; you reset your watch, but that has nothing to do with the passage of time.  Unless you are defining time only by calendars and clocks and common agreement.
457395
It's all theory, we don't know if (something) can exceed the speed of light. I would argue that time would be void at that moment, but again it's my theory. Interesting thought though.
675887
Time "IN A SENSE" does not exist and is an illusion. \nFor example: Suppose there are two syncronized clocks on two  infinately seperated walls (one behind you and one in front of you) and the clocks are illuminated at exactly 2pm by light from your flashlight that shoots to the front and the back at the same time. And lets pretend that you are in a spaceship ---with that flashlight --accelerating (speeding up trying to reach light speed) away from one clock towards the other.just as you receive the reflection of light (showing 2 pm) within your eye from the clock behind you. And lets pretend that you reach light speed the instant the light from the clock reaches your eye. At the instant you reach light speed then any light from your flash light reflected from the clock cannot reach you because both you and the light are moving in the same direction away from the clock at the same speed. At that instant, time relative to that clock would no longer exist for you in your frame of referance. Because the only image of time that you have processed in your mind is the image of the clock at 2pm. \nIf you instantly slow down below light speed by a fraction of the speed of light, then, the light from your flashlight that is in transit behind you will begin to catch you again. Depending on the speed that you are moving time will again appear to move on the clock. But each instant of time will be defined by the speed you are moving relative to the speed of the light reflected from the clock. Your flashlight is also important in that light leaving the flashlight must first travel back to the clock and then be reflected back to the spaceship where you will see it. Therefore you will see not only time changes due to the speed you are moving, you will also see funny changes in time from the fact that your flashligh is moving with you.\nAt the same instant you are moving away from one clock you will be moving towards the other clock. The time you experience relative to this other clock will be compressed in relation to the fraction of the speed of light you are moving.\nFor these reasons, time can be said to be an illusion. However, one must keep in mind that by theory, no human or any solid matter can move at the speed of light. \nAnd it must be admitted that though time is an illusion, it is an actual unchanging property of reality.
268887
As the speed of light is approached time slows.\nThis is given by the formula Sqrt(1-v^2/c^2) where\nv=velocity\nc=speed of light\n\nAt the speed of light time stops Sqrt(0) = 0\n\nFaster than the speed v exceeds c so v/c >1\n\nsqrt of a negative is imaginary.\n\nThe only thing you can see when traveling faster than a light is a snuffleupagus. (Because their IMAGINARY. or least they used to be back in the good old days.)
414182
Hmm, this one is interesting. I mean you could have left this one off with the science, but you added the philosophical point. But thats ok because it makes it so much more subjective. But, let's start with what science can prove, and move on from there. This should be interesting. Ok. Would the sun go supernova? No, because our nice little star is not massive enough, it needs A LOT more mass to go super nova. But what it will do is many years from now (hopefully) it will enter the Red Giant phase, where the Sun will expand outwards to about where Mars is. As it is doing that, yes it will burn concrete, it will flashboil the oceans, and turn our lush eden into a barren world shortly before being consumed by the sun. After that it will explode to create a planetary nebula and the suns inner core will remain and cool to a white dwarf. Now, the philosophical question. Mother nature would probably not step in because this is just another cycle, this happens to many other stars/ suns in our night sky. But, God probably would. In fact, he could come before our little star goes boom. Because remember that when he spoke to Noah, he said that he would destroy the world again, only with fire this time. So the sun destroying itself could have some part to play. But, he may not come till after it destroys itself. Now, that is if you believe the Bible. Im not sure what the Kuran or any other religious works have to say about their god or gods. Because remember, it took him from the big bang to about 35 A.D. to return, about 20 billion years. So, he may not come for another 20 billion years! Remember, his timescale is not like ours is. And thats the beauty of all this! He gave us a universe to explore, and a holy work commanding us to go forth unto the world and multiply! What better excuse to use for space exploration! I mean we have so much time that its almost insane. I feel that we have barely scratched the surface on our understanding of the universe, and that we should take steps to understand it.\n\n(Please note: Though I am a Christian, I respect other religions because last I looked, we lived in a country that allows freedom of religion, and actually, I would love to see some one from another religion answer this to see what they have to say about this)
183218
1m/s physically you are walking towards a stationary object that is reflecing your image, as such you are walking towards it at the steady 1m/s.\n\nIf not that then you are both approaching a common point at 1 m/s so you combine your velocities to get 2 m/s.  but that's semantic bullcrap\n\nYou could get really technical and add in the fact that the photons are travelling back at you at the speed of light but that's just stupid.
568438
You have the old Newtonian physics, which is called classical physics.  It is built on the premise that space and time are absolute fixed entities, and cannot change.  This is the physics that you learn in High School, and is true and works for our everyday life.\n\nHowever, when one begins to approach the speed of light, and apply the classical physics to that situation, we see violations of physical law: such as an object can go faster than the speed of light.  For example, let's say a car is traveling at half the speed of light, and you shoot a bullet that is traveling at .6 times the speed of light (all hypothetical of course).  An observer would see the bullet traveling at 1.1 times the speed of light, which is obtained by adding the speed of the car and the bullet together.  That is the classical method of finding the bullet's speed.\n\nEinstein correctly surmised that nothing can travel faster than the speed of light, or even be seen traveling faster than light, such as our bullet.  Therefore, he considered how classical physics would look if space and time were not fixed entities.  In doing so, he developed a more comprehensive physics, called relativistic physics, which fixes our bullet problem.  \n\nThe cool thing is, the relativistic equations are almost exactly the same as the classical equations, with one exception: the have what I call a relativistic adjustment.\n\nFor example, to find the bullet's speed as seen by an observer, requires the following equation:\n\nV = Vc + Vb\n\nWhich in our problem would be:\n\nV = .5c + .6c = 1.1c\n\nThe relativistic equation is almost the same:\n\nV = (Vc + Vb)/(1+Vc*Vb/c^2)\n\nThe numerator is the same as the classical equation.  The denominator is the relativistic adjustment.  So, the equation becomes with our example:\n\nV = (.5c + .6c)/(1 + .5c*.6c/c^2) = .846c\n\nThe bullet would be seen traveling at almost 85% the speed of light.  \n\nThe cool thing here is that when you use speeds that are very small, like everyday speeds, the relativistic adjustment bascially equals one, so it reduces to the classical equation.
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.