A Brief History of Light

What did people living before the 20th century know about light? Of course, from simple examples such as thunder and lightning, it is clear that light is much faster than the speed of sound. But was light instantaneous or just really, really fast? Philosophers disagreed, and for many centuries, no observations were accurate enough to decide. That is, until the invention of the telescope in the 1600s confirmed that light indeed did have a (really, really, really fast) finite speed.

How fast is light exactly?

Light travels at a speed of about 300,000 kilometers per second, which means it travels the distance of the equator 7.5 times in one second.

By comparison it takes sound (travelling through air) almost 33 hours to travel the distance of the equator just once!

How long have humans known the speed of light?

I was surprised to learn that we have known all of this since the 1670’s, when Dutch astrologer Ole Rømer used observations of eclipses of Jupiter’s moon Io to demonstrate that the speed of light was in fact finite, and even calculated the value with a fair degree of accuracy. Roemer’s publication provides the correct conception that light is virtually instantaneous for terrestrial measurements, but not fast enough to ignore for measurements within the solar system. [ ref. http://www.rundetaarn.dk/engelsk/observatorium/light.htm ]

Why does this matter?

Until the 20th century, the general consensus seemed to be “it doesn’t.” The concern was for terrestrial mechanics and nothing more. Since light travels so fast as to be virtually instantaneous on earth, no one really worried about it. For instance, Isaac Newton writes a side-note referencing that light takes approximately 8 minutes to travel from the sun to Earth, but in all of his theoretical work, he ignores light’s finite speed.

In 1886 Heinrich Hertz successfully confirmed James Clerk Maxwell’s theory published in 1865 that visible light was just a small part of a larger electro-magnetic wave spectrum. Hertz demonstrated that the signals generated by a spark gap transmitter could generate an electric field, proving that Maxwell’s electromagnetic radiation could be generated. Hertz also confirmed Maxwell’s prediction that this radiation travelled at 3.0 * 10^8 m/s, which is also the velocity for light.

At this time, interest in the precise nature of these strange new "radio waves" grew rapidly.

How does Light travel?

When you look up at the night sky, what is going on? How is the light getting from the stars to your eye?

According to Einstein, the relative velocity of the star to earth causes a bending of space-time, which preserves the velocity of light for all potential observers, whether they are traveling towards or away from the source of the light.

Tesla and Mathis, however, reject the bending of space. For them, both your eye and the distant star generate a charge field, in much the same way that all matter generates gravitational fields, and it is through this charge field that light travels.

Imagine the distant star is moving away from earth’s solar system at c/2, half the speed of light.

Einstein’s general relativity hypothesizes that the space-time between the two reference frames, earth’s and the star’s, will be bent such that both frames will calculate the speed of gravitational attraction (and of light) between the two frames to be c.

Here’s Wikipedia’s description of gravity in Einstein’s general relativity:

Formally, c is a conversion factor for changing the unit of time to the unit of space.[2] This makes it the only speed which does not depend either on the motion of an observer or a source of light and/or gravity. Thus, the speed of "light" is also the speed of gravitational waves and any massless particle. - http://en.wikipedia.org/wiki/Speed_of_gravity

So according to Einstein’s own theory of general relativity, the gravitational attraction between two objects does not depend either on the motion of an observer on earth or the star. Gravity is a mysterious field that each body contributes to, yet both observe as traveling at the speed c.

In the language of the mainstream physics' general relativity, only empty space is flat. Matter is a “disturbance” within “flat” space, which produces “perturbations.” Two bodies of matter will produce perturbations in just the right way to bend space-time so that the constancy of the speed of light (equivalently, the speed of gravity) is preserved. Notice what is happening here. Both objects are “bending” the field [space-time] through which the gravitational attraction between them occurs. 

Mathis is saying that light is generated by precisely the same kind of field as Einstein’s gravitational field in general relativity. That is, the light-producing charge field is generated by both the observer and the distant object in such a way that the speed c is preserved for both.

Mathis is saying that it is the light-producing charge field that is altered in order to preserve the constancy of c, and not space itself. Somehow Einstein missed this possibility, and thus we are left with curved space-time.

Mathis’s system is every bit as consistent as the Einstein/Lorentz system. The only question is which system best matches the empirical data. See my previous blog entry and the following excerpts from some of Mathis's papers for more on this comparison.

From http://milesmathis.com/tesla.html:  I hold that space cannot be curved, for the simple reason that it can have no properties. . . . Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved is equivalent to stating that something can act upon nothing. I, for one, refuse to subscribe to such a view. - Nikola Tesla

Tesla tells us that space can have no properties, since it is a “nothing”. Only matter can have properties, not space. I agree with him completely. And, although I accept the numerical findings of General Relativity, I do not accept curved space any more than Tesla. - Miles Mathis-

From http://milesmathis.com/rel4.html
You already know that great speed can make an image blurry, but Relativity is much more than that. Even if we have a very fast f-stop on our camera, and can get rid of any possible blur, great speed will still cause distortion. It causes distortion because the light we are seeing with must travel from the object to us. But since the object has size, different parts of the image reach us at slightly different times. If we give the object two ends, one end must be further away than the other end. All ends cannot be the same distance, unless the object is a point. And no object is a point, since a point is not an object. This means that we must get distortion, and that the distortion is due to size.

Now, according to this explanation, even an object at rest must be distorted, due to size. And this is also true. But the distortion of an object at rest is so small we may ignore it. To get any noticeable distortion due to Relativity on an object at rest, the object would have to be exceedingly large, so that light traveling from one end would arrive late. Normally, Relativity is not applied to objects at rest, and that is why.

But motion increases this effect greatly, and very fast motion increases it to a point where it becomes measurable. The reason is that very fast motion can make the farthest end of an object seem closer than it is. A small object passing you very fast will seem even smaller, since any part of the object traveling away from you will seem to be compressed. This is called length contraction.

Also from http://milesmathis.com/rel4.html
Light, like sound, has a wave. The analogy to sound is not perfect or complete, but light does have a wave. A train approaching us will have its light waves compressed and a train departing will have its waves stretched, for the same reason as we saw with the sound waves. We see the train at 100 feet, and then the train at 99 feet, and so on. We don’t see a continuous image, we create one from the still images we receive. Since the later light has less distance to travel, it makes up time on earlier light, and the wave we see gets compressed. In reverse the same thing happens as the train recedes.

Many will think this must make the receding train look longer--since waves that are stretched must be longer--but this is not what happens. The longer waves only make the train look redder. We read longer waves as redder and shorter waves as bluer, so a larger wavelength will cause a redshift.

The reason the receding train looks shorter is that the length of the train is determined by a single image. Unlike the wave, which is built of a series of images, the length is determined by one image only. In other words, we could take a picture with a real camera, and using that one image, we could determine the apparent length of the train. [And, yes, that one image would be distorted by Relativity. That real picture, taken by a real camera, would be distorted by Relativity.] Now, that one image is made up of all the light reaching us at the same instant, from all the points on the train. Since all the light is moving the same speed, the light from more distant points on the train must be earlier light. To say it another way, all the light is reaching US at the same time, to make the image, so it can’t have left all points on the train at the same time. If we work backwards from our eye, and go the speed of light for x seconds, we can reach some points on the train, but not others. This means that our image is made up of older and newer light. For instance, if the light from the nearest parts of the train was emitted at t = .0002s, then the light from the farthest parts of the train might have been emitted at t = .0001s. The light has farther to go, so to reach us at the same time, it had to be emitted earlier. If it was emitted earlier, then it was emitted when the object was not quite as far away. Therefore, the far end of the object will appear closer than it is. Therefore, the object will appear smaller or shorter than it really is.

From http://milesmathis.com/ether.html
Light, when seen or measured, is always local: meaning, it is always right in your eye or your instrument. Furthermore, it is always moving right at you when you see it or measure it. You cannot measure tangent light or light at any angle or light at any distance. You cannot measure light moving parallel to you, perpendicular to you, or moving away from you. Any attempt to measure the speed of light will be the attempt to measure light that is already impinging on the eye or instrument. ... [T]he emission and reception are both relatively instantaneous. Light is so small and moving so fast, that any motion of the emitter or receiver becomes negligible. ... This is the reason all receivers measure the speed of light to be c, and for no other reason.

Tom's note: This exact same argument is used by Einstein's general relativity to explain gravitational attraction between objects moving very fast towards or away from each other. Mathis just takes the argument away from gravitational fields, and applies it to a "foundational E/M field" that generates light, thus avoiding Einstein's warping of space.