Be gentle, I have physics textbooks on order ;) which should satisfy my cravings, until then.. I would like to try and stick a pole-in-the-ground so to speak so I can say 'all movement is an offset from here'. I've read up a little on the Michelson-Morley experiment. I believe light can travel both through a medium (when on Earth) and without a medium (when in space). I think I mean using the speed of light outside a medium. I am currently believing that nothing in the universe that emits light is in exactly the same place after it's started emmitting. Wherever the centre of the expanding sphere of light is, is the pole-in-the-ground, and is not where the source is anymore. If you take 6 light detectors and arrange them somewhere in space in a sphere, or 12 (is there a name for the number series that describes increasing the points on a sphere symmetrically?). In the centre of this sphere is a light source and you switch it on, measure when the front surface of the light wall hits each detector, then switch it off and measure when the back surface of the light wall hits the detectors. If light, either because of its speed or something else about it, behaves independently of anything elses movement once it's been emitted, would this be be picked up as a delay in the readings hitting some of the sensors? I am wondering what would be the minimum speed of our solar system/galaxy/planet/group-of-detectors for an offset to be detected, or what would be the widest sphere for the detectors to be configured in to register an offset, or both (assuming there actually ever would be an offset registered). The following are the results I'm imagining: a) The front surface of the light hits all detectors simultaneously. Shortly after so does the back surface. b) The front surface of the light hits all detectors simultaneously. Shortly after the back surface hits the detectors (or stops hitting the detectors, rather) in an offset sort of way. c) Both the front and back surface spheres of the light wall register delays of the same 'shape' and timing. d) Both the front and back surface spheres of the light wall register a delay of the same shape, the back surface registering an even larger offset but in the same direction. e) The front surface hits the detectors in an offset way and the back surface stops hitting the detectors but is offset in a different direction(!) I am not sure if this is an imaginary repeat of the Micheson-Morley experiment, which answer I should expect or what they ought to mean.