How an astrophysicist uses Codex to help simulate black holes

Chi-kwan Chan spends his days modeling some of the most violent physics in the universe: matter spiraling into black holes, magnetic fields twisting at the edge of the event horizon, light bending under gravity so strong that Einstein's equations barely hold together. He's an astrophysicist, not a professional software engineer, and that gap between science and code is exactly where Codex has started to matter.

Building a black hole simulation isn't like writing a typical app. You're translating general relativity into numerical methods that can run on a supercomputer without blowing up from tiny rounding errors. Chan has used Codex to help write and debug the kind of dense, specialized code that underlies these simulations, letting him iterate faster on the physics instead of getting stuck untangling syntax or chasing a stray index error for an afternoon.

That matters because the pace of discovery in this corner of astrophysics is unusually slow and unusually expensive. Simulating a black hole's accretion disk can take weeks of compute time, and a single bug can quietly corrupt months of results before anyone notices. Chan's workflow with Codex isn't about replacing the physics — it's about cutting down the friction between having an idea and testing it against the math that describes how gravity actually behaves near a singularity.

And there's a broader story here about who gets to do this kind of science. Simulating general relativity used to require either a large team with deep software engineering chops or years of self-taught coding grind. Tools like Codex are lowering that barrier, letting domain experts like Chan spend more of their time on the physics questions that actually matter — like what real observational data from event horizons can tell us about whether Einstein's century-old theory still holds up at the extremes.