HEADLIGHT ON A SPACESHIP

David M. Raley

On this occasion I will not undertake to explain why no object can travel faster than light but only why no object can be observed to approach at the speed of light relative to the observer. Without formulas! The formula in the second paragraph down is to explain one reason why people who know math love to use it and is not part of the main subject. It may be skipped if such makes you perspire.

The question usually goes: "If nothing can go faster than the speed of light what happens when a spaceship going 50 percent, or 90percent, or 99 percent, or 99.999 percent, or some other percent of the speed of light turns on its headlight?" Several things happen. The headlight draws current from the ship's batteries. The wires carrying the current heat up slightly. A beam of light propagates through space at the speed of light. (and) The ship slows down just a bit from the reaction. The next question is: "why is the beam not faster?" If you have asked these question of a run of the mill physicist you might have been answered: "I can't explain it without math", meaning perhaps that if you can't take the time to learn the math you aren't worthy of having an answer. If he truly can't explain it without math he probably can't explain it with math either. If you want to be equally rude ask to see the math; tolerate the rolling of the eyes, study it closely and say: "Hey, you divided by zero?" He might respond that this is elliptical math but most likely will begin to examine the part of the proof that has always baffled him and try to explain to you why he is not dividing by zero or that it is OK in this case.

Math is actually shorthand. It should not be confused with arithmetic. It should be taught as a second language. The reason many things are difficult to explain without math is that the complexity and length of the statement is such that you can't hold it all in your, pardon the computerfication of the human mind, BioRAM. Here is an example that your mind can hold all the longhand of and its math equivalent. You can skip to the next paragraph if the prospect of understanding math frightens you. Suppose I say to you: "The inductive reactance of a certain coil of wire is equal to twice the ratio of the circumference of a circle to its diameter multiplied by the frequency in cycles per second of the signal applied to said coil and thus multiplied by the reactance of said coil measured in Henrys." (A man named Henry discovered the phenomena.) To one who knows the shorthand meanings of the symbols I need only say XL=2piFL. This is one of the basic electronic formulas.

The simple explanation, without math, to why nothing can be observed to approach at the speed of light is: A Photon is an Electromagnetic Wave just like a Radio Wave. A Wave is produced over a period of time starting with no energy, developing to its maximum positive energy, falling back to no energy, developing to its maximum negative energy, and falling back to no energy. A Photon comprises a complete cycle of the Wave. When you detect a Photon you sense the changes of its energy. If the device that is sending the Photon to you is moving at the same speed as the Photon the negative energy will arrive at the same time as the positive energy and cancel it out. It doesn't matter if the Photon is generated by the headlight or is being reflected by some part of the ship.

It's as if you write a check with no money in the bank and then beat the check with a deposit.

A more detailed explanation, using only third grade arithmetic: To show that something is impossible assume that it is possible and note what the result would be. Suppose that we have a Spaceship that can travel at and above the Speed of Light. To simplify the explanation further we will deal with single cycles of the Waves and make the starting Wavelengths as long as Light can travel in one second. The cycle will be considered at 36 points. By the words "see" and "look" I mean "detect by some method". Let's have a look at Drawings.

Drawing 1 shows the vessel up close and tells how it is supposed to operate.

Drawing 2 shows how single Photons of light "look" to distant Observers as they, they being the Photons, leave the Headlight, Taillight and Sidelight with the vessel standing still in relation to all Observers.

Drawing 3 shows how single Photons of light "look" to distant Observers as they, they being the Photons, leave the Headlight, Taillight and Sidelight with the vessel moving to the right at one half the Speed of Light. The Observer on the right sees a Wave of half the Wavelength. The Observer on the left sees a Wave of twice the Wavelength. The Observer to the side sees a Wave that is at first somewhat shorter and then somewhat longer.

Since the question is "why can nothing be observed to approach at the speed of light" I will deal with the Observer on the right from now on.

Drawing 4 shows why the Wavelength is now halved for the Observer. The explanation of why the Wave doesn't lose power over the distance traveled is as follows: You know from experience that Electromagnetic Waves such and Light and Radio get weaker the farther you are away from the source. When you see a light or listen to the Radio you are detecting a small portion of the billions of Photons that are being transmitted. The signal spreads out from the source so that there are fewer Photons to reach your eye or your antenna the farther you get from the source. Our individual Photon, however, is just a strong when you receive it as when it is transmitted.

Drawing 5 illustrates what happens at 90% of the Speed of Light.

Drawing 6 answers the question of what happens at 99.999%.

Drawing 7 shows what happens at exactly the Speed of Light.

The above is true for the Observer on the right but what about the crew of the ship? This is an experiment that you can probably do yourself. If you really want to know what is observed in the vicinity of a spaceship traveling 99.999999999+ percent of the speed of light, by those who are traveling with it, when the headlight is turned on, do this: Paint a sign that says "Spaceship" and attach it to your car. Turn on the headlights. Observe what happens. Everything in the universe is travelling at 99.999999999+ percent of the speed of light relative to something. Food for thought and maybe the basis for another mindless screed:

Light is a form of electromagnetic wave that has been observed to have some particle-like tendencies. Matter is made of particles and particles have been observed to have some wavelike tendencies. Whether these tendencies are true or are artifacts of the observation process is a matter of hair-pulling controversy with some. For the foregoing discussion it was assumed that electromagnetic waves are purely waves. Properly understood, waves do not travel, they propagate. Furthermore electromagnetic waves are transverse waves. They develop at right angles to the direction of propagation. Drop a weight into a tub of water and waves propagate on the surface. It used to be thought that light travelled through ether, (aether) . Ether was the fifth element of the ancient sciences. The quintessence. (and) No, the ancients did not think that their four physical elements were all of the forms of matter. They thought that varying quantities of the four physical elements made up all forms of matter; much as you and I believe that electrons, protons, neutrons and the minor subatomics make up all forms of matter. The main reason that ether fell out of favor is not that it was proven nonexistent. (Finally, a legitimate way to employ a double negative.) They just couldn't find the math to make it be entirely a surface! To be entirely a surface ether would have to have infinite size and zero dimensions. Hold me back, I feel a mindless screed coming on.

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