Не на экзамене, но тоже из категории "эти забавные студенты".
Отсюда. Обсуждаются эволюционные треки звёзд на диаграмме "спектр - светимость" (диаграмме Герцшпрунга - Рассела).
Цитата:
Watch out!
Studies have shown that this is a topic that can introduce and reinforce a misconception about stars. When studying the evolutionary tracks of stars, we often talk about how stars "move" in the HR diagram. Students can come away thinking that an HR diagram is like a map, and what the track plots is the star's motion through space, not its changing temperature and luminosity as it evolves.
