Dark Flow or an Epistemological Limit?

Space.com brings us an article about Mysterious New 'Dark Flow' Discovered in Space. It seems that scientists are seeing things that are moving as if something incredibly massive is outside our observable universe. Really interesting stuff.

OK. Now to tread the fine line between geeking out and keeping this somewhat interesting:

To start a discussion about my thoughts on this, read what one commenter at Slashdot said:

What bugs me is that this "bubble" of the known universe really isn't a bubble at all, it's just the physical limit of our ability to observe; we have no means of determining the extent of this "bubble". Therefore, claiming that there could be "giant, massive structures much larger than anything in our own observable universe" just outside this bubble seems somewhat... convenient.

Here is another Slashdot quote:

To paraphrase David Hume: There is no reason to believe that the laws of physics have always been what they are today at all points in space and at all points in time. While it is well within reason, and quite likely, that the Universe follows neat patterns quite specifically, when one runs into really odd data that doesn't fit into your tidy boxes it might be time to rethink things. Dark matter/flow/energy or whatever the new buzzwords scientists come up with are stop gap measures meant to really say, "we haven't the foggiest idea what's going on, but it doesn't quite add up".

There are limits to what we can really know at both ends of the physical continuum. As the LHC breaks things down into smaller and smaller pieces, I have complete confidence that we will keep on uncovering more things we don't know. Similarly, as amazing telescopes look farther and farther into space and further and further back in time, I'm sure that more questions will be raised than questions are answered.

Maybe the "dark flow" is really God's left foot. Maybe it's a bunch of galaxies made out of dark matter. It seems to me that we are getting to a point where these theories are being built on a little bit of data and lots of beautiful theories.

I'm a big fan of scientific inquiry, but am sometimes skeptical about the theories they come up with for things that are very large, small, far from us, or in the distant past or future. I like many of the stories (theories) and am impressed when theories have good predictive abilities, but ultimately I feel like there is a limit to what people can know.