James Moffett 27 February 2024

Hi Geraint. I enjoyed your book, with Luke Barnes, The Cosmic Revolutionary's Handbook. In it you mention Smoller and Temple's Shockwave Cosmology inside a Black Hole (PNAS 2003) which you describe as a white hole cosmology. Although, if I understand correctly, they think that we are still inside an expanding black hole, following an explosion inside it. At first I though this seemed very strange as I though that a black hole crushed everything inside it. However I found out that during the brief time of the collapse of a star to form a black hole, there is 'flat' spacetime (like the majority of the observable universe) inside the black hole event horizon. Only later on does this expanding black hole briefly become a white hole in the surrounding space. I see that Smoller, Temple and Vogler have in made another, linked paper in which they consider that the acceleration of the expansion of the universe may be due to an under density caused by the shockwave and propose a test for that, linked, idea. I wonder if you know whether such a test has been conducted, or may be done? ( "An instability of the standard model of cosmology creates the anomalous acceleration without dark energy". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.)