Most of us know what we mean when we say that something has happened. For theoretical physicists, however, this isn't an easy question. Sean Carroll of the California Institute of Technology explains why it's hard to define events and what to do about it.
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.
Quantum mechanics seems to suggest that passive observation is impossible: the very act of looking at something can change what's being looked at. In this video interview, we talk to David Wallace and Adrian Kent to find out more.