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?
What’s the deal with redshift? How can we actually interpret velocities when it comes to cosmic expansion? And what’s with the recent tension over measuring the expansion rate?
Is light made of waves or particles? Is matter made of waves or particles? What does it mean for matter to “wave”, anyway? Why is this so hard to understand?