[omarchowdhury]

So what I take that relativity of simultaneity is showing, is that there is no "universal time" everywhere.

But this is all dependent on the positioning of the observers. The observers painted on the universal graph are all ones waiting for light to reach them. This is what is causing the confusion as to when is "now", as all the observers or points of awareness are separated in space. And I take it that, their separation in space is also what separates them in time... and thus each have different notions of when now is.

But can we not conjure an omniscient observer as our frame of reference? One who exists at all points, at all times.

Would he not be able to observe both the Earth on July 24, 2011 and what exists in the space of the water vapor cloud as Earth time is still July 24, 2011?

[Dylan16807]

Sure you can.

Pick a vector.

Any vector.

You can create an observer moving at this velocity and it'll give you a different idea of simultaneous from an omniobserver at a different vector.

Oh, and before you ask, no there is no 'unmoving' vector. They're all relative to each other with no reference frame.

[Cushman]

But can we not conjure an omniscient observer as our frame of reference?

Yes. We can not. In fact, that is precisely what the theory of relativity states: There is no privileged reference frame.

There is literally, actually no such thing as "what exists in the space of the water vapor cloud as Earth time is still July 24, 2011". As I look at my clock at noon on July 24, I see water. Someone at the reservoir will not see my clock strike noon for twelve billion years, my time, and they'll look around and maybe see no water. We disagree, but we're both right in our own frame of reference. Both perspectives are true.

Which makes sense if you think about it; your omniscient observer would have to agree with one or the other (or some other) disagreeing perspective. What criteria could you possibly use to choose between them?