Trying to Connect Some Dots Across the Galaxy...

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...and I could use some help in figuring out some possible implications and whatnot. So could james_nicoll, I suspect, for reasons I'll explain momentarily.

In my last posting on a favourite book mapping out our home galaxy, I noted the announcement of a discovery of a giant "plume" extending out of the galactic plane as posted to spaceref.com in this press release. The original announcement site, at the US National Radio Astronomy Observatory's web service, is here.

Then I stumble onto three posts on related matters here and here at James' LJ, and another one at one of his acquaintances here.

So, now I'm trying to figure out how some or all of this fits together...and what questions I should be asking next.

Comments

[(Anonymous)]

Fascinating material! This is the sort of thing I once, long-ago, tended to get into but am now years out of step with. Thanks for the reminders.

The initial press release had me first looking at the phenomenon in isolation, where the concerns were more of the nature of potential permanent loss of hydrogen-mass from the galaxy. In that narrow context I was wondering how much of that bubble's mass was permanently lost, and how much would be reclaimed over time via gravitational and electromagnetic attraction. After all, less hydrogen means lower likelihood of new stars forming. Given the distances between galaxies it struck me as likely that most of the mass would be reabsorbed by the galactic disc eventually.

As the other entries looked at the situation from other perspectives - both briefly as potential extinction events and more broadly as drive sources for evolution - it takes on more interesting slants.

Between the various entries the appropriate questions appear to be asked.

Looking backwards, how much did a similar nova-driven bubble benefit us? That's the one I find myself most intsrested in. Whether or not the one in question has been doing the same; if it has, then the fact that it's likely an event some 10-30 million years in the past becomes more significant as we look back down our own evolutionary path. Secondarily, as a process that presumably crops up here and there within a galaxy, it's of interest as another phenomenon that may have interrupted the development of intelligent life on other worlds. Implicit in some of the questioning is another question: Is the relatively cooler, rarified environment left inside the bubble an important factor in the potential development of life on any scale (time) that development into intelligent species requires? If so, is this an indicator that the closer one gets to the center of a galaxy the less likely it is that life would have been able to develop and evolve?

The idea that other, more technologically-developed civilizations would see a similar bubble-forming event coming and head in our direction is simultaneously the one most likely to be worked into new fiction and the idea I find least convincing. As much as I believe that life has to have emerged elsewhere I'm left with the reality that we've had no electromagnetic evidence of alien civilizations. Sure, there are some possible explanations for it, ranging from an advanced civiliation having gotten beyond the stage of open transmissions and having either moved to a more guarded means or technology that's not accessible to us as yet. It strikes me as more likely that where life's arisen and thrived it may not always trend towards technological development and intelligence in that direction, or may otherwise simply be taking a much longer route towards it. (eg an Earth timeline in which the mass exctinction of the dinosaurs didn't largely clear the field to allow mammals to achieve dominance.)

Mike Norton
http://miraclo.blogspot.com/

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In which case, such species as may be arising in the real universe are pretty much doomed to become anything from ashes to fossils-to-be. Which would seem to remove the most exciting possibilities from most space adventure fiction, as near as I can tell at the moment.