Some 180 years ago, a relatively normal star called Eta Carinae suddenly brightened to become the second brightest star in the sky, before almost disappearing at the end of the 19th century. The sudden brightening and subsequent disappearance, recorded by astronomer John Herschel, suggested that the star had undergone a supernova explosion, leaving behind a black hole. More recent observations have shown, however, that the star still exists – ruling out the supernova hypothesis. Even more remarkably, what remains is a binary system of two stars, the more massive of which is surrounded by a large nebula.
展开▼
