How small was the universe when the Big Bang started?
Ethan Siegel offers an opinion at Forbes: No matter how tempting it may be to think that the Universe arose from a singular point of infinite temperature and density, and that all of space and time emerged from that starting point, we cannot responsibly make that extrapolation and still be consistent with the observations that we’ve made. We can only run the clock back a certain, finite amount until the story changes, with today’s observable Universe — and all the matter and energy within it — allowed to be no smaller than the wingspan of a typical human teenager. Any smaller than that, and we’d see fluctuations in the Big Bang’s leftover glow that simply aren’t there. Ethan Siegel, “How Read More ›