Scientific Nostalgia

So, I hear the Brontosaurus might return to the rolls of official dinosaurs, rather than oopsies. From Yale mag’s “The Brontosaurus is Back“:

“Originally discovered and named by Yale paleontologist O. C. Marsh, Class of 1860, the “thunder lizard” was later determined to be the same as the Apatosaurus… But European researchers recently reexamined existing fossils and decided that Brontosaurus is in fact a separate species.”

Well, these things happen. I’m glad scientists are willing to revisit their data and revise their assumptions. Of course, I have no idea how much morphological difference is necessary between two skeletons before we start calling them different species, (by any sane metric, would a wolf hound and a chihuahua be considered the same species?) but I’m willing to trust the paleontologists on this one.

The interesting thing isn’t the reclassification itself, which gets down to somewhat dry and technical details about bone sizes and whatnot, but the fact that people–myself included!–have some sort of reaction to this news, eg:

“Dinosaur lovers of a certain age are gratified. “I’m delighted,” says geology professor Jacques Gauthier, the Peabody’s curator of vertebrate paleontology and vertebrate zoology. “It’s what I learned as a kid.””

I’ve seem other people saying the same thing. Those of us who grew up with picture books with brontosauruses in them are happy at the news the brontosaurus is back–like finding an old friend again, or episodes of your favorite childhood show on YouTube. Perhaps you think, “Yes, now I can get a book of dinosaurs for my kids and share the animals I loved with my kids!”

Meanwhile some of us still cling to the notion that Pluto, despite its tiny size and eccentric orbit, really ought to be a planet. Even I feel a touch of anthropomorphizing pity for Pluto, even though I think from an objective POV that the current classification scheme is perfectly sensible.

Pluto is not the first round, rocky body to get named a planet and then demoted: in 1801, Giuseppe Piazzi discovered Ceres, a small, round, rocky body orbiting between Jupiter and Mars.

Finding a planet between Mars and Jupiter was intellectually satisfying on a number of levels, not least of which that it really seems like there ought to be one there. For the next 50 years, Ceres made it into the textbooks as our fifth planet–but by the 1860s, it had been demoted. A host of other, smaller bodies–some of them roundish–had also been discovered orbiting between Mars and Jupiter, and it was now clear that these were a special group of space bodies. They all got named asteroids, and Ceres went down the memory hole.

Ceres is smaller than Pluto, but they have much in common. As scientists discovered more small, Pluto-like bodies beyond Neptune’s orbit, the question of what is a planet revived. Should all non-moon, round bodies (those with enough gravity to make themselves round) be planets? That gets us to at least 13 planets, but possibly dozens–or hundreds–more.

There’s an obvious problem with having hundreds of planets, most of which are miniscule: kids would never learn ’em all. When you get right down to it, there are thousands of rocks and balls of ice and other such things zooming around the sun, and there’s a good reason most of them are known by numbers instead of names. You’ve got to prioritize data, and some sort of definition that would cut out the tiniest round ones was needed. Tiny Pluto, alas, ended up on the wrong side of the definition: not a planet.

Pluto is, of course, completely unaffected by a minor change in human nomenclature. And someday, like Ceres, Pluto may be largely forgotten by the public at large. In the meanwhile, there will still be nostalgia for the friendly science of one’s childhood.