"I have an object composed of unknown materials, jumbled together in an unknown way, with unknown density. I'm going to hold it next to a light and heat source. How bright would it be?"
That sounds like a difficult problem.
That sounds like a difficult problem.
Let me just code that up real fast.
In much simpler form, it's similar to the "Where will this satellite in a decaying orbit land?"
The difficulty is not the approximation: the difficulty is that whether drag begins to increase at t=x or t=x+30sec (based on orientation when it first encounters atmosphere) cascades throughout the rest of the equations and dramatically changes the results.
We literally don't know what gases, and how much of them, will evaporate off of it until they do evaporate. And that doesn't happen until it warms up more.