If a ray of light was capable of grabbing the end of our tape measure as it passed us, it could prove to the world once and for all that the speed of light is not the same for observers at different velocities. Consider the following: Imagine we are observing a ray of light that has a frequency of 10 cycles per second, and a wavelength of 1 foot. We can calculate the speed of light to be 10 feet per second. If the light grabbed the end of our tape measure as it passed, it would pull out 10 feet in one second. What happens if we increase speed towards the source sufficient enough to double the frequency? Textbooks will tell you that as you increase speed towards the source, the frequency will increase and the wavelength will decrease. So at our new speed, how far do you think the light (in 1 second) will pull out our tape measure? Textbooks will say 10 feet, since you now have a frequency of 20 cycles per second and a wavelength of 6 inches. At our new speed, the tape measure would actually be pulled out 20 feet in 1 second. This is because it is impossible to change the distance light has to travel through space from the source to complete one cycle by simply observing it at different speeds. The number of cycles we see in a second (frequency) is completely related to our speed relative to the source. The distance the light has to travel from the source to complete one cycle (wavelength) is always the same. You cannot change the distance a ray of light has to travel from the source to complete a cycle by running into the next cycle. To plot our ray of light that has a frequency of 10 cycles per second, and a wavelength of 1 foot, we can draw a 10-inch line that represents 1 second. On that line will be 10 dots representing each completed cycle, they will be spaced 1-inch apart. If we increase speed until the frequency is doubled and then plot the new ray of light, we will now have 20 dots spaced a half an inch apart. Calculating the speed we will find that the light is still traveling towards us at 10 feet per second. Our flaw comes from not adjusting the length of our line. The length of the line does not just represent 1 second; it represents the amount of distance traveled in 1 second. So as we increase speed towards the source, we must also increase the length of our line. This will cause an increase in frequency, the wavelength stays the same, and the speed increases. At our increased speed, interferometers and oscilloscopes will both squeeze the 20 cycles on our 10-inch line. This will indicate that the speed of light does not change as we travel at increasing speed towards it. If we believe this, then we must believe that by changing our speed towards the source, we can control the distance the wave must travel from the source in order to complete 1 cycle. Try to imagine a source of light that instead of shooting out a beam of light, it shot out 1-foot rulers, one after the other in a straight line. If you increase speed towards the source you can increase the amount of rulers you pass in a second, but you cannot change the length of the rulers. Don’t let perception distort reality.