Wisp, not to sound like I'm doubting you; but what evidence do you have to support that there might be an ether out there for EM waves to propagate through. I have seen some evidence on both sides and I must say I am more inclined to believe there is no ether. The evidence supporting that claim...
So if the fourth dimension isn't time in this case; what is it? I'm just breaking into GR so I haven't even hit special relativity yet.
Sidenote: someone please tell me what a tachyon is?
:blushing: Now I feel rather stupid. Your last post made more sense. Now I feel really stupid. :redface:. We don't know what space is expanding into. We may not ever know.
I will argree this part of your statement is very true. There are many questions everywhere in every scientific field which people are striving to answer.
Russ has provided a very good explanation of your second query. If it's alright, I'd like to add to it. With space expanding, everything...