Dwarf Planets

Sometimes, ‘technology’ is nothing more than the question of what to count, and this is especially true for the term ‘dwarf planet’. This category exists for one and only one reason: to permit astronomers to say they know how many planets there are. This sounds strange, as if the astronomical term ‘dwarf planet’ was primarily about the ego of those scientists studying outer space. But this allegation is not far from the truth, and against this the only response any planet-lover worth their salt can offer is the formula: “Dwarf planets are planets too!” (Although please, be polite about insisting this.)

As my 2011 piece, Pluto and Eris – a dialogue explains, the discovery of the 2,400 km wide rock that bears the name of the Greek goddess of discord created huge problems for astronomers in that it is their professional task to speak for outer space and they desire, as all scientists do, to make ‘reliable witnesses’ (as Isabelle Stengers puts it) out of those objects they have chosen to investigate. But Eris is so very near to Pluto in size, and more importantly the Kuiper belt is so packed full of objects like Eris, the coming to human awareness of Eris-the-rock actually destroyed astronomers ability to say “we know all about the planets”, because it prevented these telescope-human cyborgs from being able to say precisely how many planets there are.

Hence the gathering of the International Astronomical Union to deal with this crisis of knowledge, and the immediate invention of a new tool, the term ‘dwarf planet’, which refers to a planet that ‘has not cleared the neighbourhood around its orbit’ (the only part of the four-part definition of a dwarf planet that other planets don’t meet). But reclassifying Pluto, Eris, and all the other newly discovered planets as ‘dwarf planets’ – which is actually a very solid scientific term, and carefully agreed to by the astronomers – wasn’t enough to defend the egos of astronomers from the cyber-hubris brought about by having found dwarf planets. So they added an additional conceptual layer to their definition, which was that “dwarf planets are not planets.”

Now poor Eris is used to being messed around, but this was rather cheeky! Indeed, she has every right to be insulted by the suggestion that – despite obviously being planets (often with their own moons!) – dwarf planets are a different kind of object entirely, rather than just a different kind of planet. It’s all so unnecessary, since astronomers are now equipped to give a much better answer to the question “how many planets are there in our solar system?”, namely “there are four terrestrial planets, four Jovian planets, and at least five dwarf planets.” The first five dwarf planets we’ve found are Ceres, Pluto, Haumea, Makemake, and Eris, and they are planets because “dwarf planets are planets too.” Pass it on.

For Anwen and Branwen and everyone else for whom ‘what counts as…’ matters.

A Hundred Cyborgs, #16