One of the nicest fields of geoscience, in my opinion, is meteorite studies. New samples come in at a stately pace, the analytical methods used on them are cutting-edge, and the puzzle being solved is the very birth and infancy of the solar system. And the nicest subfield of meteoritics centers around the rare rocks that originated on other planets. Now geo-blogger Simon Wellings has posted his experience at a recent Specialist Discussion Meeting on the early Earth-Moon system, where some of these meteoriticists let the public peek into their deepest dreams. Those involve the promiscuities of the early planets, in which impacts carried pieces of their targets into space and onto the surfaces of other worlds. Now that we can feasibly visit the Moon, we should be on the lookout there for some of that "swapped spit"Earth rocks from the Hadean Eon, for instance. Enjoy Wellings' impressions from his stimulating day.
One of my own fondest dreams in this field is that some day we might discover rocks not just from Mars, the Moon and various asteroidscool as those arebut truly precious pieces of Venus or Mercury. In 2008 I posted a bulletin on that topic that mentioned the unique meteorite GRA06128. Searching for updates today, I found that an asteroidal origin seems to still be the working hypothesis as of this year. But one of these days another candidate will turn up, I'm sure, perhaps on the Moon itself.