astroengine writes "According to two theoretical physicists, our current four-dimensional Universe (3 dimensions of space, 1 dimension of time) is actually an evolution from a lower-dimensional state. The early Universe may have existed with just one spatial dimension (plus one time dimension) up until the Universe cooled below an energy state of 100 TeV. At this point, a transition occurred when the spatial dimension "folded" to create 2 dimensions. At 1 TeV, it folded again to create the Universe we know today: 3 dimensions of space, one of time. This may sound like a purely theoretical study, but there might be evidence of the evolution of universal dimensions in cosmic ray measurements and, potentially, in gravitational wave cut-off frequency."