Why I don't believe in the speed of light

First off, let me just say that discussion about the speed of light, quantum physics, string theory, the size of the universe, although sometimes very interseting, is pointless. Why? The enormous gap between what we know and what we think we know. You can know everything there is to know about physics, but as physics knows so little about the aforementioned topics, it still amounts to nothing meaningful.

To the topic at hand. It's very difficult for the layperson to understand the theories behind why the speed of light is the absolute limit, so I'll try and explain it is basically as I can. Speed consists of two elements, distance (space covered) and time. As these two elements are linked into space-time they are simply manipulated to ensure the speed of light is not exceeded. In the example given, rather than saying the astronaut is travelling at the speed of light + 1 mph, physics dictates that time moves faster to ensure the barrier isn't broken. Conveniently time is said to move just fast enough so that whatever additonal distance the astronaut travels that would ordinarily allow her to exceed the speed barrier with time ticking away at it's normal rate, that's how much faster time will take away. An alternative is to shrink the distance covered and keep time ticking away at it's normal rate.

Imagine you were a giant. A super-huge giant, so big in fact that your arm span stretched from one side of the known universe to the other, much further than the distance light travels in a year. If you were to scratch your head, your arm would cover millions of miles in a short space of time. Surely less time than 1 year? Wrong, physics would dictate that either, time or space is manipulated so that in this instance a short space of time would be equivalent to however many years light would take to travel the distance of your arm.

Either way you can't win, despite how logical your argument is. That's why I believe all of these discussions are of nonsense value.

Originally posted by -mytym-
First off, let me just say that discussion about the speed of light, quantum physics, string theory, the size of the universe, although sometimes very interseting, is pointless. Why? The enormous gap between what we know and what we think we know. You can know everything there is to know about physics, but as physics knows so little about the aforementioned topics, it still amounts to nothing meaningful.

To the topic at hand. It's very difficult for the layperson to understand the theories behind why the speed of light is the absolute limit, so I'll try and explain it is basically as I can. Speed consists of two elements, distance (space covered) and time. As these two elements are linked into space-time they are simply manipulated to ensure the speed of light is not exceeded. In the example given, rather than saying the astronaut is travelling at the speed of light + 1 mph, physics dictates that time moves faster to ensure the barrier isn't broken. Conveniently time is said to move just fast enough so that whatever additonal distance the astronaut travels that would ordinarily allow her to exceed the speed barrier with time ticking away at it's normal rate, that's how much faster time will take away. An alternative is to shrink the distance covered and keep time ticking away at it's normal rate.

Imagine you were a giant. A super-huge giant, so big in fact that your arm span stretched from one side of the known universe to the other, much further than the distance light travels in a year. If you were to scratch your head, your arm would cover millions of miles in a short space of time. Surely less time than 1 year? Wrong, physics would dictate that either, time or space is manipulated so that in this instance a short space of time would be equivalent to however many years light would take to travel the distance of your arm.

Either way you can't win, despite how logical your argument is. That's why I believe all of these discussions are of nonsense value.

So you're saying the human mind shouldn't bother to think about it?

Yes there is space time but time as well can be a relative. Would a 12 hour flyer ( which is an insect which looks like a giant mosquito) which hatches and then flys for 12 hours then dies see it's life as lasting just 12 hours or lasting a lifetime as we perceive a liftime? What passes as a day to us would be a micro second to the galaxy wouldn't it?

Also relativity has been proven as the GPS satellites are calibrated to take relativity into account as time on board the satellite passes slower than time on earth due to their speed in orbit. So when a GPS tells you it's 12pm it is actually 11.58.2 seconds on board the satellite ( That time difference is just a number for the sake of explenation btw as I don't know the actual time difference between the GPS and the surface of the earth)

I just think I had multiple mindgasams going through this thread

reply to post by steveknows


a bit more about relativity and GPS. GPS works as predicted right? If Einstein was wrong, the current GPS system wouldn't have worked.

In order for a GPS system to achieve the 5-10m accuracy (forget about Selective availability that introduced an artificial uncertainty for civilian GPS's, that was switched off years ago), the designers had to keep relativity into account.

The current GPS configuration consists of a network of 24 satellites in high orbits around the Earth. Each satellite in the GPS constellation orbits at an altitude of about 20,000 km from the ground, and has an orbital speed of about 14,000 km/hour (the orbital period is roughly 12 hours - contrary to popular belief, GPS satellites are not in geosynchronous or geostationary orbits). The satellite orbits are distributed so that at least 4 satellites are always visible from any point on the Earth at any given instant (with up to 12 visible at one time). Each satellite carries with it an atomic clock that "ticks" with an accuracy of 1 nanosecond (1 billionth of a second). A GPS receiver determines its current position and heading by comparing the time signals it receives from a number of the GPS satellites (usually 6 to 12) and triangulating on the known positions of each satellite.

To achieve this level of precision, the clock ticks from the GPS satellites must be known to an accuracy of 20-30 nanoseconds. However, because the satellites are constantly moving relative to observers on the Earth, effects predicted by the Special and General theories of Relativity must be taken into account to achieve the desired 20-30 nanosecond accuracy.

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly. Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion.

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away. As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.

The engineers who designed the GPS system included these relativistic effects when they designed and deployed the system. For example, to counteract the General Relativistic effect once on orbit, they slowed down the ticking frequency of the atomic clocks before they were launched so that once they were in their proper orbit stations their clocks would appear to tick at the correct rate as compared to the reference atomic clocks at the GPS ground stations. Further, each GPS receiver has built into it a microcomputer that (among other things) performs the necessary relativistic calculations when determining the user's location.

So you see, relativity is not just some abstract mathematical theory. All those people always insisting that Einstein was wrong, should explain why the GPS system as implemented actually works.....

reply to post by steveknows


Your response makes my point, everything you have said is contingent on "seeing" light and you have extrapolated from there. The old conundrum "if a tree falls in the woods" is apt here, if one does not "see" light then is there any light? You assume there is and because you can "see" it your eyes are telling you exactly what it is and that "is" is fact.

reply to post by l_e_cox

Part of the relativity problem is the apparency of time shift. If your were moving away from a radiant object faster than the speed of light, once you had traveled for a longer time than it had been radiating, you would no longer be able to "see" it. ("See" really means to measure, or observe, from your own frame of reference.) Also, if you were depending on the light from it to observe it, it would appear to get younger as you moved away from it, and finally you would get to the point where you were seeing the object just as it started to radiate. Of course, this is just a trick being played on you because of the velocity of your frame of reference relative to that of the radiant object. Time didn't really go backwards; you were just using a non-instantaneous observation method.

Omitting the fact that c cannot be surpassed, one thing left out of this scenario is time delineation for the traveler. Traveling away from a radiant light source the traveler's time would slow proportionate to the degree c is being approached so the radiant source (not undergoing time delineation traveling c because it is massless, time does not exist in respect to the photon, if the photon could have such a sensory ability) and that radiant light source to the traveler in the traveler's time would reach you at exactly c because the traveler's time is slowing in respect to the radiant light source, so those photos catch up to the traveler at the constant rate of c. In fact the radiant light source would also pass the traveler at c.

I cannot speculate on what occurs if a traveler is traveling faster than c because that doesn't apply, it can't exist.

Think of a light clock, that sends a light pulse up and down between reflecting sensors that measures time in the traveler's ship. It is sending photons at c to measure most accurately time passing, billion's of times a second. Now as the traveler approaches c it means these pulses of photons have further to travel to reach each top and bottom sensor, because of the forward motion approaching c so the photons aren't slowing, they have further to go to reach each sensor now in a zig zag path instead of straight up and down. The photons from the radiant source don't have that extra travel so they will pass you by at c according to the time the traveler undergoes. It makes no difference how fast one travels, outside light will always reach the traveler at c, even if the traveler is approaching an outside light source because the traveler then is traveling into the future, so much greater time is being traveled as the same amount of outside photons approach the traveler according to the light clock, the time frame the traveler is now in.

We only know about light because we have eyes, if we didn't have eyes, and only ears, sound is all we would know, therefore, the sound barrier would be the fastest thing we know of, yet we would have nothing to 'observe' something breaking the sound barrier. Maybe something out there can travel faster than light, we just can't detect it yet or arn't aware of it.

Originally posted by GDR3k
We only know about light because we have eyes, if we didn't have eyes, and only ears, sound is all we would know, therefore, the sound barrier would be the fastest thing we know of, yet we would have nothing to 'observe' something breaking the sound barrier. Maybe something out there can travel faster than light, we just can't detect it yet or arn't aware of it.

We can measure things we can't perceive. In fact, it's being done all the time in physics.

Originally posted by Hellhound604
reply to post by steveknows

 

a bit more about relativity and GPS. GPS works as predicted right? If Einstein was wrong, the current GPS system wouldn't have worked.

In order for a GPS system to achieve the 5-10m accuracy (forget about Selective availability that introduced an artificial uncertainty for civilian GPS's, that was switched off years ago), the designers had to keep relativity into account.

The current GPS configuration consists of a network of 24 satellites in high orbits around the Earth. Each satellite in the GPS constellation orbits at an altitude of about 20,000 km from the ground, and has an orbital speed of about 14,000 km/hour (the orbital period is roughly 12 hours - contrary to popular belief, GPS satellites are not in geosynchronous or geostationary orbits). The satellite orbits are distributed so that at least 4 satellites are always visible from any point on the Earth at any given instant (with up to 12 visible at one time). Each satellite carries with it an atomic clock that "ticks" with an accuracy of 1 nanosecond (1 billionth of a second). A GPS receiver determines its current position and heading by comparing the time signals it receives from a number of the GPS satellites (usually 6 to 12) and triangulating on the known positions of each satellite.

To achieve this level of precision, the clock ticks from the GPS satellites must be known to an accuracy of 20-30 nanoseconds. However, because the satellites are constantly moving relative to observers on the Earth, effects predicted by the Special and General theories of Relativity must be taken into account to achieve the desired 20-30 nanosecond accuracy.

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly. Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion.

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away. As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.

The engineers who designed the GPS system included these relativistic effects when they designed and deployed the system. For example, to counteract the General Relativistic effect once on orbit, they slowed down the ticking frequency of the atomic clocks before they were launched so that once they were in their proper orbit stations their clocks would appear to tick at the correct rate as compared to the reference atomic clocks at the GPS ground stations. Further, each GPS receiver has built into it a microcomputer that (among other things) performs the necessary relativistic calculations when determining the user's location.

So you see, relativity is not just some abstract mathematical theory. All those people always insisting that Einstein was wrong, should explain why the GPS system as implemented actually works.....

Yes and I'm not disagreeing with you. It was also proven with two atomic clocks one of which was on the ground while the other was on the shuttle.

Originally posted by crankyoldman
reply to post by steveknows

 

Your response makes my point, everything you have said is contingent on "seeing" light and you have extrapolated from there. The old conundrum "if a tree falls in the woods" is apt here, if one does not "see" light then is there any light? You assume there is and because you can "see" it your eyes are telling you exactly what it is and that "is" is fact.

I don't know what you want. What you say just makes no sense.

So are you saying that if I'm looking at a blind man sitting under a lamp that I can't really be seeing him due to the light he's sitting under because he's blind and because it's he that is blind and can't see I therefore have no proof that light is real?

That light is only real for me but not the blind man sitting under the lamp?

Or that light bounces off me because I can see it but doesn't bounce off the blind man because he's blind and because it doesn't bounce of him he's invisible to me?

Or are you saying that blind people aren't really blind and that most of us somehow unknowingly bend light around us so in effect become invisible to the blind people?


No. light is real and it is me who is invisible to the blind man because his photon detectors don't work and when light is reflected off me and toward his photon detectors his photon detectors are damaged and don't detect.

Originally posted by GDR3k
We only know about light because we have eyes, if we didn't have eyes, and only ears, sound is all we would know, therefore, the sound barrier would be the fastest thing we know of, yet we would have nothing to 'observe' something breaking the sound barrier. Maybe something out there can travel faster than light, we just can't detect it yet or arn't aware of it.

You've never felt the sun on your face?

Yes, but without eyes how would you know it was the sun giving off light?

reply to post by GDR3k

We cannot see most of the electromagnetic spectrum, yet we can detect it.

Nothing travels faster than light?Maybe true maybe false.But doesnt darkness travel as fast as light?

IMHO the speed of light is definitely not constant. It must speed up as it crosses the event horizon of a black hole thereby disappearing. Sort of like breaking the sound barrier.

I have had plenty of thoughts on time and the speed of light. In this case I think of my thoughts on space and time itself having a sort of density. Like how the speed of sound is related to whatever is surrounding the sound wave, the speed of light is also surrounded by space. Instead of thinking space is nothing, think of space as something like a fluid. Like it is hard to run in the pool, it hard for light to travel faster than a certain speed. Or you could say if traveling faster than the speed of sound practically tears through air, traveling faster than the speed of light tears though space-time. Now, if you are in a spaceship traveling at the speed of light through the space-time density, meaning you are also traveling through the same space-time but inside the ship, you could not step forward in the same direction as the ship's velocity without tearing space-time. You were assuming that being in a space ship and the fact that the AIR in the spaceship is moving with zero velocity relative to you means it is like you are not moving at all and that you are also moving with zero relative velocity through space. The space density goes through the ship. The ship will not block the space density from interfering with you. You are still traveling THROUGH space even though you are in a ship. You move forward, you create a hole in space time. Space is not like air or matter you can't block it with a spaceship. Did I make any sense at all?

I dont think anything is impossible. Look at all the things we have done so far that were deemed "impossible" and we made possible.

Light is a mystery to me always has been.

We don't even fully understand what light even is but yet for some reason were certian that nothing can go faster then it.

Thats like saying I've never seen nor held an apple before but I know what it tastes like and it will always taste like that.

Light is just antoher barrier yet to be broken.

Originally posted by taderhold
IMHO the speed of light is definitely not constant. It must speed up as it crosses the event horizon of a black hole thereby disappearing. Sort of like breaking the sound barrier.

I didn't see your post before I posted but you made me think.

If light can be slowed by gravity and even stopped. Then why can't gravity speed up light then?

Interesting indeed.

Originally posted by Idotwhat
I dont think anything is impossible. Look at all the things we have done so far that were deemed "impossible" and we made possible.

Light is a mystery to me always has been.

We don't even fully understand what light even is but yet for some reason were certian that nothing can go faster then it.

Thats like saying I've never seen nor held an apple before but I know what it tastes like and it will always taste like that.

Light is just antoher barrier yet to be broken.

Who doesn't understand what light is? Who's we? What light is, is the most basic of science.

The visible part of the light spectrum "is" the only thing we can see with our natural eyes.


Light is a form of radiant energy that you can detect with your eyes. Light energy comes from chemical energy, electrical energy and nuclear energy. It is a combination of electrical and magnetic energy that travels very, very fast. It is estimated to travel at approximately 300 000 km per second. It can pass through anything that is transparent, sort of passes through translucent objects (frosted window) but doesn't make it through opaque objects such as a brick wall.

There are two types of light: luminous - objects that emit their own light (sun) and non-luminous - objects that do not emit light (flashlight that is switched off)

Light is made-up of photons which are very small particles of energy. When these photons move or the light travels, it travels in straight lines but in small waves. An example would be tossing a pebble into a pond. The ripples produced, (small waves) travel in a straight line away from the source, the pebble. Light shares the characteristics of both particles and waves.

Originally posted by taderhold
IMHO the speed of light is definitely not constant. It must speed up as it crosses the event horizon of a black hole thereby disappearing. Sort of like breaking the sound barrier.

Well how does it work then? Have you noticed the black hole in the black hole? That's because not even light can escape.

So if you could be at the event horizon and watch the light speed up as you say it does do you think you'd be able to see stars billions of k's away from the black hole?

Of course you would. They're further away from you than the light you say you'd see speed up at the black hole but you're seeing the light from those stars billions of k's away at the same time because their light is just as fast as the light you say you'd see at the black hole yet they're further away.

It's a constant speed.