The biggest chunk of evidence for expansion of the universe is the whole red-shift/Doppler effect deal, saying that as something that emits light while traveling away from the observer, the wavelength of the light will be "stretched" making it appear red. There is one thing I'm wondering. Could the red shift be caused by something else, like long distances perhaps. Maybe over the course of hundreds of thousands of light years, the wavelength of the light lengthens, due to maybe extremely long distances, or maybe a long term effect of the pull of gravity on the light. Does this sound reasonable, or are there any other ways it could happen? Also, it is theorized that the speed of light is constant. I'm not doubting this yet, but can anyone tell me what this is based on? If it turned out to be false, I'm sure that many theories of science in general would have to change, and that fact itself might uphold its truth, but what is it based on? Is there any experimental evidence on this? My last question is: why is the speed of light constant, why is it at that speed, and why is that the maximum speed of an object? Surely, there would be some geometrical way to exceed that speed, even if the methods seem unreasonable. For example, if one were to take a pole, say one light-year long, and swing it around at a speed in which it would complete one radian in one year, then the end of the pole would be traveling at the speed of light, so what if it was swung faster? Theoretically, anyway, I'm hoping not to get responses on how that is impossible, I'm just asking what would happen? What would happen to the end of the pole, where the speed of light is exceeded? Thank You.