Posted: 1/6/2007 10:35:06 PM EDT
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Light moves at the speed of light (c), correct? It has been proven that time slows down as you approach lightspeed; at c, time itself actually stops. So, at c...time itself should not exist, right? 
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no, the light beam would travel away from you at the speed of light. to the outside observer, your beam of light would still only be traveling at the speed of light. and so would you. so, as near is i can tell, the universe would only implode upon you. but the rest of us would be O.K. 
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But you are moving at c relative to what? because you could move at c in relation to earch and yet light would still move past you because that light would be moving at c in relation to other objects. For all we know there could be a star that is moving away from us fast enough that we are moving at c in relation to it. Thats why I never bought the idea that you could freeze time by moving at the speed of light. If you are going at the speed of light relative to the sun you are still not going to be going the speed of light relative to the stars. |
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If the universe is infinite and has existed for all time, then how can you measure it. You can not measure something without a beginning nor an end. Thus all time exists without measure; it happens that as mortals we can not see beyond our time, since we are finite. We are less than a billionth of a nano second if you must apply a measure to it, even though inaccurate. We are, and always will be a permanent piece of existence. |
Its not infinite according to most. It has an end. Everything gathered together and then the 'big bang' occured so now it is all flying away and will for a LONG time untill gravity pulls it all back in againt. Or so they say.... Also time may have never 'began' but you could still measure how fast it goes relative to other things.. Its like a train. You might have never seen the begining of it but you can still see how fast it goes by. |
Think about it, if there never was man or any other intelligent beings would time ever exist? physical dimensions would always exist but would not be observed. Simply because things repeat or move doesn't mean time exists. BTW I was just throwing a wrench into the OP's brain works, I studied Physics in college. |
Did they create a time machine? Scientists freeze a beam of light |
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According to theory, it would take an infinite amount of energy to accelerate matter to light speed, and at that speed it would take up zero volume. It's a limit equation. So, I would say travelling at c is impossible so there is always some wiggle room for light to move away from you no matter how fast you are going. As for time, light is a wave not matter so I don't think the same rules that apply to matter apply to light. |
Now what im wondering, if time is truely a product of the speed of light, if something was in a beam of 'frozen light' would time be frozen for it as well? |
But what if you go just short of c relative to the light from the sun but then a star is moving fast enough toward you that the light from it is going fast enough so that you are going c relative to the light from it? |
 No, they didn't.
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As are mine for the most part but I admit I know very little. |
Light coming from the star is still going c no matter what speed the star is going. It always propogates outward at c in every direction. Also, since your mass changes in the dimention of the direction you are going, the speed of c is constant to the observer. If you went at 1/2 c toward the sun, your mass would be reduced by 1/2, In other words, a meter would only be .5 meters according to an outside observer (you would be unable to detect this change). Light would then appear to still move at c. Mathematically, it all works out perfectly as long as it's impossible to go *exactly* c. |
If Star A is moving towards Star B at x velocity while Star C is at a constant distance from Star B would the light from SA hit SB at a faster velocity than the light from SC? Because if it wouldn't than the light from the opposite side of SA would have to move faster relative to SA than the light going out towards SB. |
OK. Try this. A photon moves from a point towards another point. It is travelling at c relative to its point of departure. An object leaves the same point for the same target point. This object is moving in the same relative frame as the photon. If the object were to move at c, time would be t=0 for the object. From the object's point of view, nothing has happened. Here's a good tidbit I found quickly: http://www.phys.unsw.edu.au/einsteinlight/jw/module4_time_dilation.htm#true "Is time dilation true? How big are the effects? Do clocks at speed really run slower, and do people or things travelling at speed live longer? One question at a time. Yes, clocks do run more slowly. Planes travel about a million times more slowly than c (so g is about 1.0000000000005), but atomic clocks are very precise and so this tiny effect effect can actually be measured. In 1971, J. Haefele and R. Keating took atomic clocks on airliners travelling both East (with the Earth rotating underneath them: we could call these "slow frames") and West (these planes have the Earth's rotation speed plus their own, and return to where they came from). Apart from some complications due to the gravitational field variations and their acceleration (which are dealt with by general relativity), this is like the twin paradox, and it gave results in agreement with the relativistic prediction. (See the original paper by J.C. Hafele and R. E. Keating, Science 177, 166 (1972) for details. Also see the diagrams and discussion about this experiment and its complications on the FAQ in high school physics.) Do people age more slowly? We don't know whether people age more slowly, because even cosmonauts don't travel fast enough for the effect to be statistically observable on their life spans*. However, people's ages are determined by physical and chemical processes in our bodies. Certainly we expect that people would age more slowly at relativistic speeds. Particles certainly do. Particle accelerators generate some short lived particles (eg muons or pions) that travel within a fraction of a percent of c, and (in the laboratory frame) they survive for much longer than their lifetime when at rest in the lab frame. Muons with a half life of 1.5 microseconds are also created several tens of km above the Earth in the upper atmosphere by cosmic rays. Travelling 50 km at c would take 170 microseconds or 110 half lives, so we should expect their numbers to be reduced by a factor of 2110 ~ 1033 (ie effectively none) to reach the surface. In fact they are measured at sea level and at various altitudes, with rates that agree with the relativistic dilation of their half lives. Time dilation happens, however counter-intuitive it may seem at first. * Low orbits are the fastest, travelling around the Earth in about 90 minutes, which gives g of about 1.0000000003. Suppose that a cosmonaut spent 2 years in space. Time dilation due to special relativity (neglecting general relativistic effects) would give an expected lifetime increase of 20 milliseconds. Lives, let alone life expectancies, are not measured that precisely! How big are time dilation effects? Note the shape of the curve above: g only starts to become large at speeds close to c. At 0.99*c, g is 7. But in many modern devices, electrons are accelerated to higher speeds than this. In a typical electron accelerator used to treat cancers, the electrons have an energy of 20 MeV (see Module 5). The speed of such electrons is 0.9997*c and g is 40. Now of course an electron cannot go much faster than this, but it can have a lot more energy. In the Large Electron-Positron collider in Europe's nuclear research lab CERN, electrons (and positrons, or anti-electrons) were accelerated to energies of 100 GeV. For such particles, v = 0.999 999 999 95*c and g is 200,000. Yes, time is slowed down by that factor. And the momentum is increased by that factor too: something that is rather important in the design of the collider because these electrons must be turned to go in a circle. Nature can produce even larger particle energies. Some particles striking the Earth's upper atmosphere have energies that exceed 2*1020 eV. If such particles are protons (with mass of about 1 GeV), their speeds would be 0.999 999 999 999 999 999 999 995 c. For them, g is 1011. Now the age of the universe is about 13 billion years for us, but for such particles, the age of the universe would be about (13 billion years/1011), ie about a month. Such a particle could cross the visible universe in a matter of months (their time)." |
No. Think of it this way, when a car is driving toward you, or away from you, does the sound "hit" you faster or slower? No. The sound waves propogate past you at the same speed, but the frequency changes. Light is a lot more complicated though, and all I can say is if you don't understand, you need to get a book on special relativity because it would take me typing pages and pages of text and diagrams to make it clear. Here is a cool web site that tries to make it all make sense: www.phys.unsw.edu.au/einsteinlight/. This link specifically is good: www.phys.unsw.edu.au/einsteinlight/jw/module3_weird_logic.htm |
Doppler effect. 
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My shit clicks on and off at random times. I'll try to remember to post here when my brain turns on. Usually it will start with a friendly debate face to face. I'll throw some people through loops, whereas some will welcome a nice non-googled conversation / discussion. Eat=McDonalds throw ^ twice? 
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I believe you are incorrect, partially anyway. Special relativity observes that the "normal relativity" the we realize (truck A 50 mph due east, truck b 50 mph due west, can be relatively seen as truck A stopped and truck B at 100 mph) DOES NOT apply to the speed of light, which is constant no matter how fast you move relative to light. For example, if you are driving truck A and some jackass shoots a laser beam at you from directly in front going c (the speed of light) the relative speed of the laser beam is c, NOT c + 50 mph. This is observable in laboratory experiments. So, since light does NOT follow the same rules we expect from truck in "normal" relative motion, something HAS to break to make the difference. What breaks is spacetime. This is why you get space curvature and time dilation effects as seen by an outside observer as you accelerate closer and closer to c. It allows c to remain constant to an outside observer by simple changing the distance traveled and time elapsed. That said, to someone in a spaceship traveling at c they will not observe any time dilation or space curvature within the spacecraft, as it is not required in their frame of reference. Trying to wrap my head around relativity is a minor hobby of mine, but I may be incorrect (I know I'm incorrect in detail, but I'm summarizing). |
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I understand E=mc^2. It's trying to explain how c is a constant regardless of frame of reference that is hard for people to get. I remember my physics teacher showing us these stupid basic animations showing the same object moving at c from three separate points of view. One from the object, one from earth, one from some other object traveling in another direction. In all cases, light coming from the object is arriving at c and the object is always traveling at c. Hence the term "relativity." The object was merely a way to show relativity--the film was not trying to imply something other than em can go c. However, there are all sorts of theories out there on how to propel objects at or beyond c. Particle tunneling, inertial nullification (or negation? can't remember, been a while), warped space (not warp speed like star trek), etc. Of course, all of these ideas are essentially attempts to circumvent relativity by making the object itself move extremely slowly whereas the space around it actually moves. |
When they remake "The Graduate" in 2150 the line will go something like this:
If it's two words it may be "quantum entanglement". ETA: Although I should be clear quantum entanglement is not for moving things at the speed of light, but builds the theoretical foundation for creating a transporter for Scotty to beam us up - as long as there's a classical information channel moving at c or slower involved as to not fuck up causality. |
Well, sort of. More like "as far as we care it is". Eventually thermodynamics catches up, all energy in the universe ends up in a completely disordered state due to the increase in entropy, and every proton in the universe has winked out of existance. Even if "time" is infinite, eventually there will be nothing in the universe but emptiness. |
Actually anyone in the spaceship would never see the light from the headlights, because from their perspective the light instantly redshifts into non-existence without ever leaving the headlight lamps. The way light, time, and matter interact probably proves that the universe will suffer a 'cold death'. An atom can toss off a photon and move to a lower energy state. When a photon hits an atom it excites it up an energy state. Since time does not exist for photons, photon paths travel both forward in time and backward in time (photon tracks have no 'arrow' on a Feynman diagram), and the fact that we have entrophy probably means that in the future there are fewer photon/matter interactions, which could be caused by an permanently expanding universe. |
Believe it or not, despite the fact that it all seems incredibly irrelevant, the implications of a lot of it are behind a lot of the damn near magical technological advances of the second half of this century. |
Frankly, I don't know what makes entanglement work, I'm not sure anybody does that I have read or at least understood, but the cool part about it is that the interactions take place before light from particle A could reach particle B. The classical rule is, because nothing can go faster than the speed of light, the fastest any information or cause and effect can travel from point A to point B is at c. So if the Sun blew up, being what, 8 light-minutes away, not matter what we could NEVER actually know about it until 8 minutes after the fact. My question has always been and I have not found an answer, is how does gravity relate to this cause and effect restriction? |
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It is my understanding that time slows down for you, traveling near light speed, relative to others. At light speed, time may stop for you, but not for those you left on earth, who progress through time at a much faster rate than you do. Soooo.... As you surpass the speed of light (assuming you overcome the whole increasing mass issue) does your own personal time reverse? Does such a prospect translate into the ability to arrive back at earth at the same time, or even before, the time you left? We won't know in our lifetimes, but probably have a much better grasp in the next 1000 years.
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Consider that space-time is just one thing, with everything moving through space-time at the speed of light, measured as an aggregate of a things speed throgh space + its speed through time. As it moves faster through space, it moves more slowly through time, and vice versa, though the total speed is still equal to the speed of light. |
everything that has a beginning has an end...........................
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