What keeps physicists up at night?

Q2C festival (www.q2cfestival.com ) opening event aligned a panel of physicists that were asked by the moderator
Wilson Da Silva (http://www.twitter.com/wilsondasilva) what keeps them up at night?

Sean M. Caroll wonders what is this universe we are living in and why its laws are the way they are?

Katherine Freese, a Dark Matter expert, is questioning of what our universe is made of? What is the Dark Matter? She's excited that in few days a paper with experimental data about this will be published.

Leo Kadanoff tries to see how physics complexity can be used to understand other complexities like financial markets or living things. .

Laurence Krauss is wondering if we are at the limits of empirical science as result of the tremendous progress that physics made in the last. 30 years. One universe is not enough to answer our questions.

Gino Segre considers that we should think crazy and wild ideas following the examples of Einstein and other great minds that had their greatest discoveries at ages between 23 and 25. He thinks at night at: "what is the craziest thing I can think off so I can sleep at night".

David Tong used to think off how will he ever know if the string theory is valid? To his surprise he learned that the theory can be used as a tool for other unexpected purposes. This fact makes him sleep at night.

You could watch the lecture on this link (http://www.q2cfestival.com/play.php?lecture_id=7976

To be continued...