By Robert Adler
From the BBC Earth website
The universe is flat and why that's important
Inflation [theory] also gave cosmologists the measuring tool they needed to determine the underlying geometry of the universe. It turns out this is also crucial for understanding how the cosmos came from nothing.
Think about the "underlying geometry" of anything at all in this somethingness we call the universe. However flat or not flat it is, it is always perceived from within the universe itself. Everything is always in relationship to something else. And then to everything else.
It is only when we grapple with describing the "underlying geometry" of nothing at all that the mind implodes. Just to contemplate it requires being a something that can.
And even if the universe itself is construed as flat how can this "flatness" not in turn be in or on or under or over or around or next to something?
Like everything in our somethingness world always is.
Einstein's theory of general relativity tells us that the space-time we live in could take three different forms. It could be as flat as a table top. It could curve back on itself like the surface of a sphere, in which case if you travel far enough in the same direction you would end up back where you started. Alternatively, space-time could curve outward like a saddle. So which is it?
This sort of speculation is often discussed in documentaries on the Science Channel here in America. Or in a PBS/Nova doc.
I watch as they introduce all of these elaborate graphics in an attempt to illustrate the point. And all the while I'm thinking that only because something exist that allows them to do this are they actually able to do it at all.
They attempt to explain the existence of space-time as a sphere or a saddle. Or with a balloon being inflated.
But ever and always their attempt to explain something presupposes the existence of the something that they are already in.
I can't even imagine how they would go about moving beyond theories bursting at the seams with all manner of equally theoretical assumptions to arrive at nothing at all.
And yet this point itself is almost never raised by them.