Space Mysteries: An international team of astronomers is on the hunt for objects that should be impossible. Could the "missing stars" be a completely new phenomenon? (Image credit: Tobias Roetsch) Stars don't just vanish — or do they? For thousands of years, astronomers accepted the idea that the lights in the sky were fixed and unchanging. Even when it became clear that these lights were actually physical objects like the sun, one of the key assumptions for astrophysicists has been that they go through major changes very slowly, on timescales of millions or billions of years. And when the most massive stars of all — which are many times heavier than the sun — do go through sudden and cataclysmic changes as they reach the ends of their lives, their passing is marked by the unmissable cosmic beacon of a