Can galaxies ever get destroyed? What happens to their stars? Do galaxies ever die?
What does it mean for the universe to have a center? Could we ever travel to ours? What is a singularity?
How does length contraction work in relativity? Do moving objects really get shorter? What about from their perspective? How are we supposed to make sense of any measurement?
What is the “cold spot” on the cosmic microwave background? Why shouldn’t it exist? What are some possible explanations for it, and why are they unsatisfying?
How do planets get tidally locked? What are these systems typically like? Can life find a home in such a challenging environment?