Have cosmologists glimpsed signs that the universe is bounded?
Gaze deep into the night sky, and space appears to extend infinitely far in all directions. Given such a view, it's mind-boggling to think that space might be bounded. Yet, just as the flat-seeming Earth is in fact a sphere, infinite-seeming space may curve in on itself to close up into a compact shape. Recently, the debate over the shape of space took some new twists. In the Oct. 9 Nature, a team of mathematicians and astrophysicists proposed an exciting idea. The universe may have a particular finite shape, modeled on a 12-sided geometric object known as a dodecahedron, they propose. The same week, a second group of scientists announced findings that may refute that proposal.