Wondering what conundrums give physicists sleepless nights? If the suggestions posed at a panel at the Quantum To Cosmos festival are to be believed, they're all to do with whether or not reality is what we think it is...

The panel discussion between nine physicists included the question "What keeps you awake at night?" and the answers can be reduced to, essentially, one simple thought: What if we don't - and can't - know everything?

New Scientists listed the main concerns from the panel, but what connected them all was the issue of whether or not our current knowledge was too limited; from Caltech's Sean Carroll wondering about the existences of other universes with entirely different laws of physics to Katherine Freese of the University of Michigan wondering what the 96% of existence that's not made of matter is, the issue really seemed to be about what we don't know. We're drawn, in particular, to Anton Zeilinger, professor of physics at the University of Vienna, and his concern:

Zeilinger specialises in quantum experiments that demonstrate the apparent influence of observers in the shaping of reality. "Maybe the real breakthrough will come when we start to realise the connections between reality, knowledge and our actions," he says. The concept is mind-bending, but it is well established in practice. Zeilinger and others have shown that particles that are widely separated can somehow have quantum states that are linked, so that observing one affects the outcome of the other. No one has yet fathomed how the universe seems to know when it is being watched.

Is the act of attempting to satisfy our curiosity about the universe creating more mysteries to be curious about? If so, then Lawrence Krauss' concerns about the limits of empirical science may have more weight than you may think... Something that cosmologist Neil Turok finds worth investigating:

We're used to thinking of theoretical physics as accidental. We need to ask whether there's a more strategic way to speed up understanding and discovery.


You can watch the full panel below:

Seven questions that keep physicists up at night [New Scientist]