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?
What’s so bad about Venus, besides everything? How did it get so bad? And are we next?
What is the “cosmic calendar”? What are some important scales in the universe? Why is it so hard to judge “importance” of events?