I think this is a good place to ask this question that I’ve had in mind:
Let’s say we’re several decades into the future and now have a perfect telescope that can identify and measure the relative velocity of every single star in the observable universe. Not only can this telescope do those things, it can also determine the age, size and type of each of these trillions and trillions of stars. At this moment, this superscope, known as the SS, takes a snapshot of literally every thing out there.
Since we’re so high tech now, we’ve also developed a super duper computer known as the SDC. The SDC is linked to the SS, so that all of the data collected is immediately stored. Connected to the SDC is the greatest 3D printer ever developed. Let’s call it the G3DP. This G3DP can immediately create a mini-replica of the universe as seen by the SS. In just a few moments we have nice little desk globe-sized replica of the universe as seen by SS just a few moments ago.
At this point, one might ask, isn’t this mini-universe created by the G3DP an accurate map of the universe? The answer would be “no”. In reality, the light coming from stars that are furthest from us is a lot older than light from nearer places in the cosmos. So you can’t say it’s accurate because each of the trillions of stars recorded is as of a different point in time in it’s life cycle. We can’t say that replica is a true map of the universe as it is today.
But hold on, remember that the SS was also able to capture all of that other data about every star. So the SDC knows that the red giant 5 billion light years away is now a black hole and the other star at the edge of our replica has now become a neutron star and about to merge with another one. The SDC can basically “forecast” the current position of every star observed by the SS when it took its snapshot.
So now we ask the SDC to have the G3DP print out a new replica, this time adjusted for time and distance; i.e. the current position of everything out there.
Can we now say that this replica is truly an accurate map of the universe today?
Next,
It turns out that another advanced civilization billions of light years away happens to do the exact same thing, at the exact same point in time, using the same (or equally powerful) technology as us. Certainly its replica would look different then ours. After all, that civilization’s observable universe is different than ours. There are places that it can see that we can’t, and vice versa. So the 2 replicas won’t be the same. However, since both civilizations can observe each other, there are portions of the replicas that are common, particularly everything in the space between us, plus extended to portions beyond.
If we just viewed the common space that exists within both replicas, will it look the same?
For argument’s sake, assume that the SDC can adjust for gravitational lensing, gravity from dark matter, etc. when producing its forecast.