There was productive conversation by email today about RR Lyrae stars in deep, multi-epoch visible data among Willman, Zolotov, and myself. Their models (by Governato et al) suggest that there should be a few RR Lyrae detectable in the 100 to 400 kpc range, even in SDSS Stripe 82, if only we can do robust detection below the individual-epoch detection limit. That kind of thing is my bread and butter. Do I feel a collaborative NSF proposal coming on?
In the afternoon, the high-energy physics seminar was by Adam Brown (Princeton) on
bubble nucleation in the eternal-inflation (string-theory-inspired)
metaverse. It seems that in many natural situations, the most likely
bubble to nucleate in our neighborhood (future light cone) could be to
a disastrously different vacuum, perhaps even one in which there would
be no volume at all (it seems you would just get mashed against the
expanding bubble wall). This has implications for our fate, though
the standard anthropics
(about which we are pretty skeptical at
Camp Hogg) protect this theory from making any falsifiable
predictions about our past. I used to say that astronomy was only
about the past light cone, so perhaps I should be ignoring
these subjects?
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