Some physicists believe that the universe is spatially unbounded[citation needed]. The theory of relativity places a firm upper limit on the speed at which information can travel. Nothing except hypothetically Tachyons can travel faster than light. This effectively divides this infinite space into "local" universes. Our observable universe, for example, is a sphere centered on the Earth (centered, that is, on whoever is doing the calculating), currently about 46.5 billion light years in radius. Thus, there are an infinite number of regions of space the same size as our observable universe â?? an infinite number of observable universes, that is. This infinite set (which must contain, among other things, an infinite number of identical copies of you,[5] the nearest of which is about m away, and an equally infinite number of not-quite-identical copies) comprises the level-I multiverse. By the Bekenstein bound there are only a finite number of configurations possible within any region, hence exact duplication is inevitable. Overtly or not, physicists often use the idea of an Open Multiverse when evaluating theories. For example, Max Tegmark writes: ...consider how cosmologists used the microwave background to rule out a finite spherical geometry. Hot and cold spots in microwave background maps have a characteristic size that depends on the curvature of space, and the observed spots appear too small to be consistent with a spherical shape. But it is important to be statistically rigorous. The average spot size varies randomly from one Hubble volume to another, so it is possible that our universe is fooling us â?? it could be spherical but happen to have abnormally small spots. When cosmologists say they have ruled out the spherical model with 99.9 percent confidence, they really mean that if this model were true, fewer than one in 1,000 Hubble volumes would show spots as small as those we observe. This was done with Apo 3D Hack - Thanks to Chromotron for his fantastic Scripts - Photoshop - Solar Cell Plugins