The physics of observers
Since he Universe is all there is, there's nothing for it to expand into. So what does "expansion" mean?
Quantum mechanics suggests that observers can influence the outcomes of measurements. If that's the case, then do these observers need to be conscious? Does consciousness play a special role in physics at all?
Modern theories suggest that the Universe really is unimaginably large — perhaps it's infinite, but even if it's not, it's so large it may as well be. But does this sheer scale affect how we reason about cosmology? In this video interview, we talk to David Wallace to find out more.