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posted by Fnord666 on Thursday September 19 2019, @09:07AM   Printer-friendly
from the expanding-like-a-waistline-on-Thanksgiving dept.

Arthur T Knackerbracket has found the following story:

Reproduceability is key to science. A one-time “eureka!” could be the first step in a paradigm shift — or it could be a fluke. It’s the second, third, and hundredth measurements that put theories to the test.

That’s why recent measurements of the universe’s expansion have piqued interest. Even though astronomers have applied multiple methods relying on completely different physics, they’re still getting similar results: Today’s universe appears to be expanding faster than what’s expected based on measurements of the early universe. Can systematic errors explain this discrepancy? Or are new physics required?

Now Wendy Freedman (University of Chicago) and colleagues have posted a new, "middle-of-the-road" measurement on the astronomy preprint arXiv, adding a twist to the ongoing debate. The study will appear in the Astrophysical Journal.


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  • (Score: 3, Insightful) by Immerman on Thursday September 19 2019, @04:58PM (2 children)

    by Immerman (3985) on Thursday September 19 2019, @04:58PM (#896152)

    Quite so. In fact, if the decay of inflationary energy propagates at light speed, while the expansion is much faster than that, then the most reasonable conjecture is that our universe is one tiny bubble of collapsed energy in a nigh-endless sea of still-expanding inflationary energy. Presumably a sea populated by a nigh-infinite number of *other* bubbles of decayed energy that started from a different spontaneous decay, which may or may not closely resemble our own observable universe.

    Of course, without some form of FTL we'll never be able to reach the edge of our observable universe, much less the edge of our "universe bubble". And even with FTL, matter as we know it probably couldn't survive outside that bubble, so unless we come across a wormhole connecting to another bubble with the same decay-state as ours, there's probably no way to confirm that. Ironically this kind of "parallel universe" seems to be both the most credible, and the least accessible, among the several kinds that might exist.

    There's also another implication - there's no guarantee that the decayed vacuum energy in our observable universe is at the lowest-possible energy state - some fleck might spontaneously decay further and trigger a new chain reaction expanding at light speed - and our first warning would be when the bubble of fresh decay swept over our planet, destroying everything in its path at a subatomic level. In fact that might have happened several times already - I don't think there'd be any way to tell for sure.

    As for infinite universe (multiverse?) - I haven't heard any convincing argument for that. Only nigh-infinite. For inflationary energy - even FTL expansion is still not infinitely fast, and thus there's a limit to how much it could expand in any noninfinite amount of time. Though I suppose that there's no guarantee that inflation hasn't been occurring for an infinite amount of time - just because we like beginnings doesn't mean the universe cares. For the several other classes of "parallel universe" that might exists (I think I've heard of at least a half-dozen that are generally considered credible) similar limits seem to exist.

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  • (Score: 2) by HiThere on Thursday September 19 2019, @07:33PM (1 child)

    by HiThere (866) Subscriber Badge on Thursday September 19 2019, @07:33PM (#896225) Journal

    The trouble is, the nature of time isn't well understood outside the context of space-time, so how can you assert that there hasn't been an infinite amount of it? So. Maybe it's not infinite. But what are the grounds for making an assumption in either direction?

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    • (Score: 2) by Immerman on Thursday September 19 2019, @11:41PM

      by Immerman (3985) on Thursday September 19 2019, @11:41PM (#896291)

      Fare enough. However, given the complete lack of evidence that infinity is anything other than a conceptual absurdity, betting against the existence of infinite amounts of anything is generally the more respectable option. At the very least, nobody will ever be able to prove you wrong - there's not enough space in the observable universe to put an infinite amount of anything.

      Even infinitesimals, the one class of things you might reasonably imagine there being an infinite number of, run into problems with spacetime granularity when considering the real world. There are in fact only a finite number of distinct points that exist between two space-time locations, or so the theory goes. Really throws a wrench in Zeno's Paradox, and may help explain why we are in fact capable of motion