Chaotic formation of galaxies
On my other blog I've just written a piece on planetary science -- The Transplanetary Perspective -- suggesting that it might become possible to extrapolate the formation of stars and galaxies backward in time, perhaps eventually tracing individual stars back to the particular stellar nurseries in which they were born. If we could do this, we could determine which stars (and associated solar systems) ultimately derive from the same clouds of gas and dust, and may therefore share certain chemical properties, and therefore share certain mineral resources in their planetary systems. As I said in the above-captioned post, planetary sciences so understood will enable us to find the resources crucial to the development of a future interplanetary or interstellar civilization: this is the petroleum geology of the future.
While this would be admittedly very difficult -- i.e., recovering earlier states of the galaxy, and determining the origins of particular stars -- it is not at all impossible, and after writing The Transplanetary Perspective I recalled an experiment in chaos theory that is particularly relevant in this connection. There was a now-classic episode of the PBS series NOVA from 1989, The Strange New Science of Chaos, loosely based on the now-classic book by James Gleick, Chaos: Making a New Science. The NOVA documentary features the work of Jerry Gollub and Harry Swinney on fluids in turbulent motion (i.e., nonlinear dynamics). There is a sense in which galaxies can be considered a fluid in turbulent motion. Indeed, a galaxy presents a paradigm case of nonlinear dynamics.
Carl Sagan, in Episode 10 of Cosmos, The Edge of Forever, said that, "A galaxy is a fluid of billions suns all bound together by gravity." In the NOVA episode cited above, Jerry Gollub is quoted as saying, "The entire universe is filled with fluids in turbulent motion." We could extend this observation, in the spirit of Sagan's metaphor about galaxies being fluids, and say that the universe itself is a fluid in turbulent motion. Moreover, fluids in turbulent motion not only converge on a strange attractor, that describes the boundaries of the chaotic movement (so that it is not entirely chaotic, or totally random), but also exhibit conservation and restoration behaviors. For example, under controlled laboratory conditions, a fluid in turbulent motion can be reversed and largely (although not perfectly) restored to its original state, prior to being subject to turbulent mixing.
I think that it would be possible, with a sufficiently powerful supercomputer, and a sufficiently exhaustive map (and history) of the stars of the Milky Way (or some other galaxy), to run the nonlinear dynamics of the Milky Way backward and to recover the origins of our own sun and solar system, and to determine its source and what other stars came from the same stellar nursery. This would tell us what kind of stellar nursery produces stars and solar systems that can produce life and civilization. Of course, as noted above, this would not be simple. We would have to account for the gravitational interaction of the Milky Way with other galaxies in its local group, and for the early natural history of the Milky Way, its particular pattern of population I, II, and III stars, the patterns of nucleosynthesis and the dispersal of heavier elements through supernovae, the patterns of supernovae, what kind of supernovae they were (type Ia, Ib, Ic, II-P, II-L, IIn, IIb), and so forth. All of this would be difficult, and would involve a lot of approximation and estimates, but I do not think it is beyond our present capacity to obtain a reasonable approximation of the evolution of the Milky Way.