My wife and I were having one of those convoluted discussions about aliens visiting Earth. Her theory is it happens all the time. My theory is “why would they bother?” I mean, would you travel 10,000 years at the speed of light just to check out where human hearts are? Which of course, let to the debate over whether travelling at the speed of light is even possible. She says of course, I say not likely. So, I did a little research. I stumbled accross this exchange on the Google Physics forum:
- From special relativity‘s (SR’s) view point: An observer travelling at light speed will not notice anything different than an observer at rest. However, it is not possible to push mass to the speed of light, as the energy required would be infinite. I don’t believe SR is correct. I think that the mass itself will not change. A perception of mass increase is caused because forces weaken near light speed. This also is responsible for the time dilation effect.Basically nothing will happen to mass at light speed. But an observer travelling along with it will see strange things happen (not according to SR). In both cases a stationary observer will record an infinite increase in the mass of the object that travels at the speed of light. I dont believe the mass will breakup.
- if one doesn’t believe in SR, one should not fly in airplanes either, or anything that uses GPS systems. GPS systems DEPENDS on relativistic corrections to make those accurate positioning, which would go haywire if SR and GR are not taken into consideration.
- Luckily, physics doesn’t depend on “beliefs” or “tastes”. Nothing is more convincing than having a tons of experimental verification done everyday, even by the very same people who do not believe in it. To which this guy included this reference: The relativistic band structure and band-gap bowing factors of ternary II-VI semiconductor alloys containing Cd, Zn, Se and Te are calculated by the ab initio self-consistent pseudopotential method with spin-orbit correction. The disorder in these alloys is modelled by the virtual crystal approximation (VCA). The numerical results thus obtained are compared with experimental data from photoluminescence spectroscopy. The experimental band-gap bowings for this family of alloys are always concave upwards. However, CdSexTe1-x and ZnSexTe1-x in general show much larger bowing factors than Cd1-xZnxSe and Cd1-xZnxTe. The former two alloys show a minimum in the band gap versus composition curve near x=0.35 while the latter two have it at x=0. Most of these qualitative trends are well explained by VCA. However, in order to explain the large bowing in the first two alloys, some kind of local order has to be incorporated in the calculation. It was found that a local cluster with AuCu-I-like structure, when relaxed, has quite a significant contribution to the bowing factors. The splittings in the band structure due to both spin-orbit and structural relaxation effects are also discussed.
- The basic point of relativity is that “speed” is a relative concept; i.e., it only makes sense to talk about the speed of an object with respect to another. The physics for one object (i.e., its properties on its own reference frame) stays the same, regardless of its speed wrt all other objects. For instance, you and I are just now travelling at close to light speed with respect to many quasars out there, and I, for one, am not feeling any effect.
What was never answered was, can a person actually travel at the speed of light? I know “speed” is a relative term, and I know if two things approach each other at a relative speed of light strange things will happen. But, I want to know what happens when an object obtains the speed of light itself. Does its matter scatter in a burst of energy? Does it just go flying off in all directions? Does it remain intact and you just travel at the speed of light until you apply the breaks? If you can, does the current debate on distorted time apply? I mean, you’re probably cranking out some pretty massive energy to travel that fast, will it distort time? What happens if you hit light travelling at slower speeds? What happens if some physical item gets in your way ( wondering asteroids et al )? If I can get some logical answers to all that, then I might buy the UFO theories a little more. But right now, I’m still convinced they have better things to do than travel 100,000 years to draw pictures in crops.