AAS DPS 2008: Jogging the planets
If you didn't realize it, Ithaca was a good place for DPS. Cornell put on a concert for the planets. The art museum has a special Saturn exhibit going. But one of my favorite things is down the hill from Cornell: the planet walk. Named in honor of Carl Sagan, the planet walk was unveiled in 1997, but has a slightly retro, 1970s feel to it. A little hokey, but endearingly earnest and fun nonetheless. You start at the heart of the Ithaca Commons, downtown, with a concrete monument to the sun, adorned with factoids. A circular hole within the monument sets the scale: that is the diameter of the sun, at one 5-billionth of its size. The planets, each with their own monument, stretch out from there, their distances based proportionately on their orbits. I decided to go for a jog out to Pluto, to really get a sense of the solar system's scale.
The inner planets all lie within a block. Jupiter, the size of a silver dollar in its sun-sized hole, sits by the famous vegetarian Moosewood Restaurant a couple blocks away. Saturn, its plastic all scratched up, is further out, in front of the Tompkins County library. I only had to run for less than 10 minutes to get this far, but the next stages of the jog were daunting. Uranus was in a little residential park, Neptune out along a canal that leads to Lake Cayuga. Pluto, finally, was tucked away by Ithaca's "Sciencenter" a mile or two away (it seemed like billions and billions), a perfect resting place for our favorite dwarf planet (Sciencenter staff said that they would be updating Pluto's factoids to reflect the current controversy). And with the conference over, I could use some rest myself. Ithaca was wonderful. If, as Sagan said, the universe was bigger than anything anyone has dreamed of, then Ithaca was my cozy little solar system for nearly a week. Until next time, Eric.
They're still arguing the 'is Pluto a planet' question. I've got to be honest: without much of a stake in the debate (i.e., not being a PI to an icy planet that became a dwarf one) I can't muster that much energy for it. But I'd still be scared of arguing with Hal Levison, who spoke earlier this weekend at a special session on the question.
Lots of weather-related Titan talks at this DPS, and it's no surprise, coming from a confluence of maturing Cassini science and an approaching equinox. Titan, which has a year of 30 Earth years, had its summer solstice in 2002. In the next couple years, its north pole will heat up (relatively speaking) as it emerges from winter, and the prevalent methane and ethane lakes will begin to evaporate as clouds form and carry moisture in a giant convective cell that stretches from pole to pole. Pictured here is a Cassini snap from February, with a streaky cloud visible near the north pole: an early sign of spring. “The weather patterns are likely to change fairly rapidly, and that could be quite exciting,” says Ralph Lorenz of Applied Physics Lab in Maryland. The polar lakes grow in winter and shrink in summer, the thinking goes. Ralph points out that sci-fi master Arthur C. Clarke had that same thought back in 1976 in "Imperial Earth". “It was sort of prophetic, in a way,” he says. An excerpt, courtesy Ralph: 
Sometime soon, astronomers are going to announce an Earth-sized extrasolar planet in the habitable zone of its star. And not too long after that, telescopes are going to be able to actually get an image of these things – albeit as a crude, unresolved, disc-averaged blob within a single pixel of the telescope's camera. There are modelers who spend their time thinking about what that blob should look like, and whether its spectroscopic signals would represent something Earth-like. But the models are quirky and need some ground-truthing. They need some Earth-truthing.
Could a renegade, retrograde ice ball signal a new population of distant bodies in the solar system? Brett Gladman of the University of British Columbia in Vancouver was on hand at a press briefing here to describe his discovery earlier this year of a 50-kilometre chunk of ice that doesn't fit with known populations. It was discovered with a Hawaiian telescope, as a part of a 
And so Sakada's maps show gravity highs in nearside impact basins, where the underlying dense rock was allowed to well up to the surface. Impacts on the farside, however, only partially excavate the thick, less dense crust, creating a ring-like basin that is a topographic, and gravitational, low. Hopefully that's enough explanation to help you figure out which picture here came from which side of the moon. 
Well, I've arrived at the Division for Planetary Sciences meeting of the American Astronomical Society here at Cornell University in Ithaca, New York. And lemme tell you, Ithaca is GORGES. (For those that don't get the town slogan, just navigate the hilly campus for a bit: most traverses of campus involve a suspension bridge or two.)