As if all the weird stuff about the Universe couldn't get any more weird, along comes this excerpt from an article in the Jan. issue of New Scientist...
It seemed to have been kicked into touch, but now the notion of a "ball-shaped" universe is bouncing back, thanks to a look at the radiation left over from the big bang.
The idea of a balled-up universe was first proposed in 2003 by Jean-Pierre Luminet at the Paris Observatory, France, as a way to explain some odd patterns in the cosmic microwave background - the afterglow of the big bang. The CMB contains warmer and cooler splotches, which reflect the density variations of the universe in its youth. This fits nicely with cosmological models, except that if you blur the microwave map into big enough pixels, the splotches disappear and the map looks less random than you'd expect - and nobody can explain why.
Luminet and his colleagues suggested that this might be because the universe is finite, but is wrapped around on itself. This means that if a spaceship could cross the universe and "exit" through one side, it would still be in the same region of space but would "re-enter" from the opposite side of the universe. Because of this wrap-around effect, images of everything in the universe would appear to be repeated in the CMB. The best way to explain the data was if the universe is like a dodecahedron - a ball-like shape with a surface of 12 identical pentagons.
