In 1977, the philosopher David Malament argued that, without an all-seeing point, no observer could fully determine the global structure of their spacetime. Only from an all-seeing point could enough information be gathered to definitively know whether the Universe has a wide variety of global properties, including an origin. In 2009, the philosopher J B Manchak demonstrated that Malament was right. Building on Malament’s proposal, Manchak showed that it is impossible to determine the overall structure of any spacetime without an all-seeing point. From any specific point within a spacetime, observers can never be certain of the global nature of their spacetime. Furthermore, all observations fit multiple possibilities – the data you have gathered from your specific past light cone can be explained by several different, even mutually exclusive, models of spacetime. In fact, all of the past light cones from all points in one spacetime (with one set of global features) can have qualitatively indistinguishable counterparts in another spacetime (with entirely different global features). Let’s refer to this result as the Malament-Manchak theorem. It suggests that spacetime’s global features remain unknowable.

For the full story, please visit https://aeon.co/essays/scientists-are-no-longer-sure-the-universe-began-with-a-bang.