Jul 18th 2011, 14:47:27
Detmerp: The example it meant to be simple, and so is meant to mean the glass is on Earth, explaining why the water falls. It's an attempt to describe why space can expand faster than the speed of light, and why matter can't. Water and light have limiting factors (water, since it is falling through another fluid, is limited to a terminal velocity; matter would need an infinite amount of energy). Space is more of a volume though, rather than an actual thing, similar to the space within the glass. So, because space has no mass, it can expand as far and as fast it feels, just like the glass not having some limiting factor, allowing it expand as much as it likes. Practically, the glass would have a limit, but this is hypothetical, and is my interpretation of things. Whether or not it makes sense to you isn't my problem, but it's how I make sense of it.