Shape of the Universe

Is the universe flat? The Earth was once, remember? Some say it still is. Or did they finally fall off the edge? Point A to point B, a straight line, right? It's certainly linear thinking and science tends to be that way. Now NASA agrees (with the cool sounding caveat that their findings are, of course, "within the limits of instrument error"). Armed with new data from WMAP, the concensus is we are set along a flat plane.

The shape of the universe:

The amount of dark matter and energy in the universe plays a crucial role in determining the geometry of space. If the density of matter and energy in the universe is less than the critical density, then space is open and negatively curved like the surface of a saddle. If the density exactly equals the critical density, then space is flat like a sheet of paper. If the density is greater than critical density, then space is closed and positively curved like the surface of a sphere. In this latter case, this implies that initially parallel photon paths converge slowly, eventually cross, and return back to their starting point (if the universe lasts long enough). The Inflationary Theory, an extension of the Big Bang theory, predicts that density is very close to the critical density, producing a flat universe, like a sheet of paper. WMAP has determined, within the limits of instrument error, that the universe is flat.

Tags: shapes, universe