The discovery of 2003 UB₃₁₃, an object larger than Pluto orbiting at a far greater distance, has called back into question the debate as to what a “planet” is. The media is already dubbing it the tenth planet; but given this, 2003 EL₆₁, Quaoar, and Sedna, my loyalties in the “Planet/Kuiper Belt Object” debate are starting to fall to the KBO side. This is surely not the last significant Pluto-like body we’ll find out there, and there’s a good chance Pluto is simply just another one of these objects, icy spheres with highly eccentric orbits a great distance from the sun. If that’s so, it can’t rightly be termed a planet, unless we’re willing to start calling every large KBO a planet as well. We’ll have dozens of “planets” before we’re done cataloguing all these objects. Yet I can’t bear to relegate Pluto, with all its historical significance, to a nomenclatural dung heap.

Currently, “plutino” is used to refer to Pluto-like bodies in the outer solar system with a 3:2 mean motion resonance to Neptune’s orbit. If we want to properly distinguish planets from large, rocky, icy orbital bodies, while also maintaining Pluto’s stature as the first of these bodies to have been found by modern astronomy, I suggest we expand the term “plutino” to cover KBO’s and trans-Neptunian objects and such. It’s a nice, compact word, and it somewhat simplifies our understanding of the outer solar system. I’m not sure our current astronomical taxonomy for the local neighborhood needs further complication in the way it classifies and labels various objects anyway.

More from the Bad Astronomer.

Cassini has found evidence of possible ice volcanism on Enceladus, based on a warm spots in the “tiger stripes” (those blue surface features) around the moon’s south pole, and a tenuous atmosphere containing water vapor — especially concentrated at the south pole. All the signs point to a geologically active moon, kneaded and heated by Saturn’s gravitational influence, and constantly leaking heat and water to replenish its thin atmosphere and coat the surface with ice.

I remember that the spacecraft in Arthur C. Clarke’s 2061: Odyssey Three were driven by water-powered muon drives. If that science fiction technology ever becomes reality, worlds like Enceladus will be a dream come true. (Especially since Europa might be off-limits if the Monoliths have their way. ;-)

More Enceladus flyby photos from Cassini. Also check out The Planetary Society’s article on the flyby.

A Rocket to Nowhere. Maciej of IdleWords provides a wonderfully detailed background of how the shuttle came together amidst bureaucratic Cold War paranoia, and how America’s manned space program today is falling behind the successes of NASA’s unmanned push. The writing and research are superb, and the analogy to Portugal constructing a massive artificial island as foil to the “explorers” analogy is perfect. (Thanks to filmgoerjuan for the link. Now I know why Maciej’s bookmarks have been full of space stuff lately.)

Isn’t it great that we now have the technology to stick an astronaut to the end of a robot arm and have him peel troublesome grout from a space shuttle’s belly in orbit? Next stop, the moon! Oh wait, first we have to see if the flimsy cloth we use for insulation might not fly off in the wind. Then, next stop, the Mars!

The funny part is, when we finally do get on our way to “The Moon, Mars, and Beyond,” it looks like our spacecraft will be old-fashioned capsule-on-rocket stacks in the Golden Age Mercury/Gemini/Apollo tradition, with parts cannibalized from the existing Space Shuttle System. So after all these years of piggybacking the orbiter on a foam-covered fuel tank with solid rocket boosters, we go back to multi-stage rockets, capsules, and parachutes — and find that those old ways worked better and cheaper after all.

Not to say that the shuttle is a complete failure. It was a great idea on paper, and one that would have worked if we only had the money and hardware to be able to produce powerful rockets which could deliver huge payloads without having to worry about compromises of mass and funding. That’s something the Russians seem to have done well early on with their Vostoks. A lot of these design problems with foam and orbiters-astride-fuel-tanks and such would be less of an issue if we only had ten times the thrust of a Vostok 8K72K or Saturn V, plus unlimited, no-holds-barred freedom and funding to design all sorts of outlandish launch vehicles made of impervious armored materials capable of flying around space while repelling just about any kind of impact or radiation. Like a starship! Yeah! Get on it, NASA!