Thank you for posting this. I'm not an astrophysicist, but I'm involved in a project that involves classifying certain time-varying sources. I therefore thoug

Thank you for posting this. I'm not an astrophysicist, but I'm involved in a project that involves classifying certain time-varying sources. I therefore thought it was pretty rock-solid that black holes DO exist because my collaborators (astronomers at Caltech) refer casually to blazars (http://en.wikipedia.org/wiki/Blazar http://en.wikipedia.org/wiki/Blazar) and AGNs as black holes. They have never qualified these statements. Thus, yesterday's article (with its very strong claim, literally, "there is no such thing as a black hole") puzzled me, and I didn't believe it. And, there was no pushback in the HN comment thread, which was a double surprise. The article you've linked mentions the difference between stellar-mass black holes that result from gravitational collapse, and larger black holes that, in the best-known cases, are at the core of galaxies and form differently. This caveat helps give some context to the question. I note that the article you link, and the earlier article, are clearly still in conflict, because yesterday's article flatly denies these super-massive objects are black holes.