There is a sense of emptiness when you finish any film because you're empty and you can't give anything more to it anymore.
Black holes are pretty scary when you ponder them. They seem nihilistic, infinitely destructive on an inconceivable scale, notwithstanding the ideas of Hawking radiation.
I remember from my school days Archimedes jumping into his bath and displacing water and coming up with his famous principle, and of course Isaac Newton being hit on the head with an apple. In other words, this realm of human knowledge - which is mathematical, essentially - can have a playful visual element to it.
I wanted to be a police detective. In my work, particularly in documentaries, I am obsessed with finding things out, seeking ever-new facts and perspectives - each project can involve years of research.
The issue often with films is how it works with money and trying to get a visible movie star presence in the film.