"What's inside a black hole and could we fly a spaceship inside?" asks Jorge Luis Alvarez from Mexico City.
Some interstellar fieldwork is on the agenda in today's Curious Cases. Astrophysicist Sheila Rowan explains how we know invisible black holes actually exist. And cosmologist Andrew Pontzen is on hand to help cook one up.
But which of our intrepid doctors will volunteer to fly into the heart of a black hole?
You can send your Curious Cases for the team to investigate to: curiouscases@bbc.co.uk
Presenters: Hannah Fry, Adam Rutherford Producer: Michelle Martin.