Reinventing Discovery_ The New Era of Networked Science - Michael Nielsen [68]
Not all astronomers and astrophysicists find the quasar mirror explanation convincing. To some, it seems a bit too convenient that the quasar has switched off. Another group has put forward an alternative explanation for the voorwerp, involving a different type of source in the nearby galaxy, a source that is also black hole–powered, but that is not a quasar. This presumed source is called an active galactic nucleus (AGN). It’s a super-massive black hole that’s emitting what’s called a jet, a narrow cone of plasma tens of thousands of light-years long. By chance the jet is aimed in the direction of the voorwerp. The jet heats up the gas in the voorwerp and causes it to glow. So in this explanation the voorwerp isn’t a quasar mirror, it’s an AGN mirror (again, loosely speaking)!
As I write, astronomers and astrophysicists are still trying to figure out which explanation is correct. But regardless of which explanation is correct, or even if some ohasexplanation is needed, the voorwerp is fascinating. Suppose, for instance, that it really is a quasar mirror. As we’ve seen, this means that the voorwerp is a huge collection of mirrors, echoing the light of the quasar at many different times over the quasar’s lifetime. That means light from the voorwerp is a bit like a biography of the quasar, and by examining the voorwerp very closely we may learn a lot: how the quasar lived, how it died, and maybe even how it was born. That makes the voorwerp tremendously important as a way of studying the life cycle of quasars. Similarly, if the voorwerp is really shining because of a jet from an AGN, studying the voorwerp will be a great way of learning more about AGNs. In either case, astronomers are excited by the possibilities, and plan follow-up investigations aimed at getting a more detailed picture of the voorwerp. Observation time has been obtained on some of the world’s most in-demand telescopes, including the Hubble and other space-based telescopes. From these and other observations we will learn more about the voorwerp, and perhaps about quasars or active galactic nuclei, too. The story of the voorwerp is just beginning.
Redefining Science’s Relationship to Society
We take it for granted that science is for the most part done by scientists. Part of what makes Hanny’s Voorwerp exciting is that it violates this assumption. How remarkable that a 25-year-old schoolteacher has discovered this great and beautiful cloud of gas! How unexpected that an amateur could make a discovery that might change our understanding of quasars or active galactic nuclei! When the discovery of the voorwerp was announced, it was a media story all over the world, receiving coverage on CNN and the BBC, in The Economist, and in many other major media outlets. Although I was delighted for Hanny van Arkel and the Galaxy Zoo team, as a writer my first feeling about all this publicity was a certain selfish disappointment, thinking that I would need to remove the voorwerp from my book, and replace it with a fresher example. But after more thought I decided to leave the voorwerp in: the media splash itself illustrates just how strongly we take it for granted that science is done by scientists, and how fascinated we are by exceptions to this rule. The headline at CNN says it all: “Armchair Astronomer Discovers Unique ‘Cosmic Ghost.’ ” What a shock and surprise that a nonscientist could make a significant astrophysical discovery!
Galaxy Zoo and the voorwerp are part of a bigger story about how online tools are gradually changing the relationship between science and society. One of the most fertile areas where this is happening is citizen science, with projects such as Galaxy Zoo recruiting online volunteers to help make scientific discoveries. In the first half of this chapter, we