Having pointed out that the BVG theorem presupposes the existence of a classical spacetime, Carroll goes on to cite some evidence that the universe did not have a beginning, based on quantum mechanics (QM): If you need to invoke a … Continue reading
There is a theorem due to Borde, Guth, and Vilenkin which might be taken as evidence for a beginning of time. Roughly speaking, this theorem says that in any expanding cosmology, spacetime has to be incomplete to the past. In … Continue reading
Our best theory of gravity is classical General Relativity. "Classical" is physics-speak for not taking into account quantum mechanics. So we know that classical GR has to break down during the Planck era, if not later. Classical Big Bang cosmology … Continue reading
The next topic from the Carroll-Craig debate which I wish to discuss is what Science has to say about whether or not there was a beginning. Was there a first moment of time, before which the universe did not exist? … Continue reading
I've written a pop-article about Time Machines and Event Horizons, which has appeared on the Scientific American blog Critical Opalescence. George Musser, my host, is an editor at Scientific American, and kindly gave me this opportunity to talk about some … Continue reading
