I devised this using a setup that I found easiest to imagine, while trying to be clear on how modern physics considers space to expand. We have a nifty device that can cause spatial distortion (no, you cannot has one!). Before we use it, we lay down two meter rulers, end to end. They both look the same, so we get down to business. Turning on our device, we expand a cubic meter of space to twice its original size. I have three basic questions. I'll provide my current answers, based on how I understand space to work. Number 2 is my most hazy. I treat the cut off between normal and expanded space as being sharp rather than smooth, for convenience. 1) What has become of the one meter ruler where our space has been expanded? 2) What happens if we pick up the unaffected ruler and place it halfway into the expanded space? 3) What happens when we shoot a beam of light across the expanded space? I say "we" to make you partly culpable if the experiment breaks the universe. My answers are: 1) To the external observer the ruler appears twice as large. 2) The part we put in the expanded space will become larger, and then shrink to a percieved normal once removed. 3) This seems to be a nice example of relativity. Since the external observe would measure the external dimensions of the space as 2m, light apparently moves twice as fast. So we must assume that light, at least, behaves as if the expanded space were two meters across. However, an 'internal' observer inside the space now would see light moving at half speed. And so we must conclude apparent time dilation. I was interested to note that the external observe can use the internal observers clock and ruler to get the correct speed of light, instead of his own, but he can't use his ruler and the internal observers clock, or vice versa. So there's my take. One question about it is the use of relativity here. Part of me sees that the light can clearly be seen by both observers to travel at the correct speed, since the external observer can see the ruler and understand that the light isn't actually moving faster, just that space is bigger. Is the issue then that light will naturally take twice as long to travel across the expanded space, therefore requiring relativity to keep c constant? In a sense, light is not affect by expanded space in the same way the ruler is (assuming I even answered question 2 correctly? Comments?