THE SPEED OF LIGHT | 2005-11-07
I don't know how many young people have been right by the track when a train went by tooting its horn. When I was a kid and the train came by we would make a pulling motion over our heads and the engineer would reach up for the cord and toot his whistle for us, long and loud.
As the train moved toward us the whistle was very high. The train was moving, so the waves came to us faster and sounded higher. After it passed us the whistle had a lower pitch. It was kind of a "WHEE-ooooooh" sound.
People noticed this before Einstein was born, and it was called relativity.
Einstein developed the Theory of SPECIAL Relativity. Just as sound differs with the point of view of the person standing still, so things are different between things traveling at or near the speed of light and things standing still.
Einstein made some excellent observations on this basis, but like all theorists, he tried to explain EVERYTHING with it and he ran into what I call The Bob Problem:
It doesn't WORK.
Einstein insisted that the speed of light was the fastest anything could travel. So it takes eight minutes for light to reach us from the sun.
So far, so good.
But then he said that the speed of light was the fastest ANY force could travel.
Huh-oh!
Actually, gravity moves MUCH faster than the speed of light. We have not been able to measure the speed of gravity, it may be infinite. But we do know that a gravity shift from the sun has an instant effect here on earth while light is coming toward us at light speed.
Einstein therefore inserted a cheat factor to take care of that inconvenience. He said gravity was a curve in space. I am not going into the details here, but it doesn't really make any sense. He just needed it and put it in.
Like all theorists who outlive their time, Einstein died a scientific reactionary. The last part of his life was spent fighting quantum physics, which is fully accepted today because it WORKS.
But this whole business of light speed is something we will have to deal with. You have watched satellite broadcasts on cable television, and the people talking sound a little retarded. A question is asked and there is a noticable delay in the reply.
With short wave radio we didn't have that problem. If you are in Baghdad and I am here, the radio waves travel the six thousand miles between us directly. At the speed of light it takes the signal one thirteenth of a second to get to Baghdad, so there is no noticable delay.
But the satellite is 43,000 miles up. So the signal has to go all the way up there and back, some 86,000 miles, which takes half a second at light speed. That means the question and answer gap is a full second. In the give and take we are used to on the news, that is a very noticable delay.
What else moves faster than light?
This is not a practical matter right now. I suppose that when it comes to the speed of light we are about where Ben Franklin was in the matter of electricity. He tried and tried to think of some way electricity might actually be practical, but finally stated flatly that he couldn't even imagine one.
By the way, the terms current, positive and negative and battery were all invented personally by Franklin.
So what I am saying here is just fascinating to me the way electricity was to Franklin. But they may become practical. I understand that some uses have been found for electricity since Franklin's time.
So what is faster than light? Gravity is, but using gravity for anything practical is as weird an idea as using electricity was to Franklin.
What about ESP? It take years to contact anyone in another star system at light speed. But if I were in ESP contact with someone there, would the contact be light-speed or instantaneous?
This sounds like science fiction, right?
Do you happen to know who invented the entire satellite communications system we use today, every day, cable TV and all?
It was invented in a science fiction story written in 1947 by Arthur C. Clark. At the time no one could imagine it could have the slightest use outside of science fiction.
So let's let Ben Franklin have the last word on this.
He was doing one of his experiments and some Practical Man asked him, "But of what USE is this?"
Franklin replied, "Of what use is a newborn baby?"