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Sunday, January 16th, 2011 09:22 pm

Brian Greene wrote a NY Times op-ed about the implications of the accelerating expansion of the universe. As he says,

Because of this, when future astronomers look to the sky, they will no longer witness the past. The past will have drifted beyond the cliffs of space. Observations will reveal nothing but an endless stretch of inky black stillness.

If astronomers in the far future have records handed down from our era, attesting to an expanding cosmos filled with galaxies, they will face a peculiar choice: Should they believe “primitive” knowledge that speaks of a cosmos very much at odds with what anyone has seen for billions and billions of years? Or should they focus on their own observations and valiantly seek explanations for an island universe containing a small cluster of galaxies floating within an unchanging sea of darkness — a conception of the cosmos that we know definitively to be wrong?

I'd thought before of the implications for scientists from future races that never had the chance to see other galaxies at all. Before reading this I'd always just assumed that we humans would be okay (assuming we survived that long) because we'd been lucky enough to see the truth. But now I worry that he has a point: assuming we survive that long, how much will those future scientists really trust our observations, so at odds with what they can see for themselves?

That's related to one of the philosophical realizations I've had about studying things like string theory and cosmology: Some true things are simply impossible for us to observe or measure, and many more are just not the sort of thing one can predict. It's hard to be comfortable with that: I'd like to imagine that I live in a universe that's not just understandable but verifiably so, but there is no guarantee that our universe will cooperate with that desire. The thought that it might cooperate for a while and then stop is especially uncomfortable: what might we miss if we don't develop the technology to observe it fast enough?

Monday, January 17th, 2011 04:14 am (UTC)
Quick thought -- it seems like this is the sort of issue historians deal with all the time. It's a hell of a lot easier to determine truths of the Battle of Gettysburg if everyone can observe it happening. However, we only have primitive accounts of the event by people who were busy commanding armies and/or being shot at. It would be a lot easier for historians if they could re-run the Battle of Gettysburg over and over in a lab, but they can't.

As for missing technology to observe things, I think cosmology is moving so slowly that we'll be either all dead or a galaxy-spanning intelligence by the time any of these issues come around.

What isn't changing slowly, however, is our civilization, and the transitions that will take place over the next 100 years or so should be unprecedented. There's probably a lot we can learn about emergent order in complex systems and numerous other things that we're just not observing right now, and will never get to observe.
Edited 2011-01-17 04:15 am (UTC)
Monday, January 17th, 2011 11:30 am (UTC)
Well, yes, the time scales of cosmology are a wee bit slow: the issues here aren't all that likely to be relevant for any given civilization. But I agree that similar sorts of phenomena may show up in other areas of human knowledge.

As for historians, I'm probably just a snobbish physicist. I've always taken comfort in not needing to trust the ancients on anything, knowing that I can always just check their claims myself if necessary. It's startling to think that my field isn't as immune to that as I thought.
Monday, January 17th, 2011 09:27 pm (UTC)
"It would be a lot easier for historians if they could re-run the Battle of Gettysburg over and over in a lab, but they can't."

Who says?

(I kid, I kid.)
Tuesday, January 18th, 2011 03:31 am (UTC)
Hey, we've got a copy of that! Never played it, though: a bit in-depth for our usual gaming groups. How is it?
Tuesday, January 18th, 2011 07:06 pm (UTC)
I haven't played it, either. I'm not a Civil War guy; more WWII.

As an older AH title, I suspect it's decent, but it has holes. The older AH games were a great foundation for the wargaming hobby, but the state of the art has proceeded apace.