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?
How hard is interstellar travel? What are the possible ways to achieve the required energy? Is there anything at all feasible in the works?