The universe is a funhouse?

[unixronin]

More accurately, according to this PhysicsWeb article¹, data from the Wilkinson Microwave Anisotropy Probe, which studies and pams the cosmic microwave background, indicates that the Universe may be "a cosmic hall of mirrors" -- a Poincaré dodecahedral space some 43 billion light--years across.  A Poincaré dodecahedral space is a finite, multiply-connected, positively-curved space manifold which can be represented as a dodecahedron whose opposite faces are "glued" together like the ends of a Möbius strip, but with a 36° twist.

In other words, the Universe "wraps around", in such a way that it is possible to make straight-line journeys of infinite length in a finite universe.  Each time you, the traveller, reach the "edge" of the universe, you "wrap around" to the far side; but such transitions come 43 billion light-years apart, you are unlikely to ever transition at the same point twice, and your view of the oncoming space is rotated at each transition.  To make it more complicated, there isn't even actually a real "edge", any more than a circle has ends.  If you travelled 50 billion light-years in a straight line, knowing the shape of the universe, you would know that you had "wrapped around" at least once somewhere in there; but it would be impossible to determine where and when (and the concept of "where" the edge is may well, in fact, be completely meaningless in three dimensions).  If you did not know the shape of the universe, it is unlikely you would ever notice that you had "wrapped around" to the far side of the Universe, and were in fact travelling through the same space over and over and over.²

[1]  Link from mrmeval

[2]  Well, assuming, that is, that you were travelling really frelling fast.... at a back-of-the-envelope first-order estimate, you'd have to be travelling better than 0.9999C to live long enough to make a circuit.

Comments

[jilara.livejournal.com]

Heck, I swear I've had that experience just in navigating Sacramento!

[mrmeval.livejournal.com]

Philip Hose Farmer should be told, I bet he'd get a laugh.