Where does the quantum world begin? Why do we have a hard time fundamentally understanding quantum systems? What connects quantum and classical physics?
What’s it like to fall into a black hole (again)? What does the outside universe look like? Is there any way to avoid your grisly fate at the singularity?
What is chaos theory? How can something be both deterministic and unpredictable? Is there are hope at all for physics?
How do cracks appear in spacetime? What does it have to do with symmetry? Could we ever hope to find a cosmic string?
Why is it so hard to predict solar eclipses? How did Newton and Halley team up to solve it? What have we learned from solar eclipses since then?