Cardboards are actually quite good at heat insulation. If you have an electric oven (no flame) and put the temperature below 200°C (ignition is at a slighly higher temperature but oven aren’t precise), there is no risk. So you can totally reheat pizza at 180°C on its cardboard.

IIRC the orbit of Mercure doesn’t work with Newton Model, and astronomers were predicted the discovery of Vulcain a small planet between Mercure and the Sun. So a new model had to be invented since Vulcain couldn’t be found.