Early in the day, undergraduate Mitchell Karmen (NYU) blew me away by showing a possible Trojan satellite hiding in the Kepler false-positive bin. It probably has some other explanation, but damn it's exciting! I discussed this with Rodrigo Luger (Flatiron) who dampened my excitement (for good reasons).
At stars meeting, Michele Bannister (Belfast) spoke about ways in which we might use the properties of the outer Solar System (and especially the things past the Kuiper Belt and including the Oort Cloud) to constrain the birth environment and subsequent dynamical environment of the Sun at formation. It appears that these structures could be created early and are strongly modified by nearby stars and close passages. One implication is that different stars should have very different Oort Clouds. That's a great prediction; now how to test it?
Mike Blanton (NYU) showed some very cool results from the work being done on SDSS-V robot fiber positioners. As you might guess, the positioning of fibers on a focal plane by robot arms that can collide is an intractable problem in general—it's like traveling salesman. But you might also know that most NP problems are pretty well-served by sensible greedy algorithms. That is, you can usually do something akin to the simplest thing and still succeed most of the time.
Blanton showed the interesting thing (worked out by Conor Sayres at UW) that if they do a greedy algorithm to take the robot arms from the "home" state to the configuration they want, it is very slow and hard, and it still fails in many cases. But if they do the exact same greedy algorithm the other way—that is, to take the arms from the configuration they want back to the home state—it works fine! So they do that and then run the result backwards!
Crazy talk. And cool. And worthy of a lot more thought. And something about entropy? After all, the home state is like a crystal.
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