Aside from science, my major intellectual interest is in psephology, the study of elections. It’s not often I get to combine the two. Science, as a general rule, is not a democracy. Questions are decided on facts, not opinions.
However, some matters can never be settled entirely on evidence. One such is the definition of objects such as planets, galaxies etc. The demotion of Pluto from planet to dwarf planet aroused such angst because there simply is no right and wrong answer. Facts are relevant – the fact that Pluto is a lot smaller than was thought when first discovered, the detection of several other objects of similar size – but there really is a lot of opinion in it too.
Pluto’s status was determined by the 400 astronomers who happened to be there on the last day of an international conference, and many of those not present were every bit as annoyed as the general public.
Personally I support the decision on Pluto – even before the vote I described it as a trumped up Kuiper belt object. But I also value process, so I appreciate the efforts being made by Professor Duncan Forbes of Swinburne University and a German colleague to engage a wider audience in the next such decision. The question is how we define a galaxy. We know the Milky Way and Andromeda are galaxies, that’s easy. Not too much of a problem to include the Large and Small Magellanic Clouds. However, there is increasing evidence that Omega Centauri, previously considered the largest globular cluster circling the Milky Way should be considered a galaxy in its own right.
The pair have produced a paper considering the merits of five different ways of drawing a dividing line between galaxies and clusters, some of which have Omega Centauri on one side, some on the other. Rather than coming to a conclusion, he’s created a website to allow anyone who wants to to vote. However, unlike those silly polls run on media websites, he does ask that people make an informed decision, ticking a box saying they have read the paper.
The vote has no binding power, but astronomers may well choose to take it into account when they get round to settling the question. If nothing else it will encourage people to talk about astronomy more, which is no bad think in my opinion.
If you’re interested: go vote.
One quibble though – the ballot is just first past the post, no preferential voting allowed (although you can cast equal votes for several options). As an Australian Forbes should have known better.