It all depends on your philosophical stand point. But technically the glass is always full, half air, half wine..
And YOU are the centre of the Universe. ALWAYS.
Think about this, your head has been in EXACTLY the same position for your entire life. every time you turn your head you are rotating you body which rotates the earth and the Universe around you.
Every time you walk somewhere you are staying in the same position you're just rotating the Earth under your feet and because the Earth is so large it just looks like you're moving.
As for the Universe and borders; we have no idea what is beyond the cosmic background radiation at the furthest reaches of space. They may very well be hiding the end of the Universe.
On the other hand you may want to consider the Universe as a 4 dimensional object as opposed to the 3 dimensional space we perceive.
This would imply that every point in the Universe is connected to every other point in the Universe in the 4th Dimension. And so therefore you may decide to travel in a straight line trajectory to the ends of the Universe only to wind up back at Earth significantly sooner than you had initially anticipated.
EDIT:
Well more or less I don't mean in a physical sense. See think about it this way, if the world shrinks, what happened to the space it used to occupy? Is there just more empty space? Or did that space shrink with the world? If that space shrank, what is left in its place?
Mind = Blown
Are you talking about compression of the Earth or about the Earth spontaneously losing mass?
In either case you've got mass extinction on your hands.
Compression would result in the crust becoming super-heated from increased Geothermal energy and would vaporise all liquid water on the surface as well as magma spewing out of weak points in the crust.
But if Earth lost enough mass for it to be significantly measurable, the amount of energy that would be released would be so incredible it would be like a tiny supernova.
You know, because E^2 = (pc)^2 + (mc^2)^2
What would happen to the space though?
There is very very little pressure in space. So so little pressure. The relatively minuscule size of the Earth losing volume is not going to have much of an effect on the rest of Space. It's like dropping a needle in a haystack and then measuring how much the Earth moved because of it.