If confirmed, a recent finding may be one of the more interesting outcomes of cosmological research in quite some time. Possibly interesting enough to keep everyone busy while they are retooling the Large Hadron Collider.
First a bit of background. Assume the big bang happened. When we look out at galaxies near and far we find that they are all moving apart in exactly the way we would expect them to be moving if the entire universe was expanding. The nature of this expansion is a bit spooky, and there is more than one way to describe it (not necessarily alternative ways). But the bottom line is that the Universe in which we live … the one to which the rules of physics are expected to apply uniformly, the one containing all the things you could possibly visit if you had a Star Trek style starship … is much larger than we can see, about 16 or 17 billion years or so (maybe as old as 20).
(You will see different estimates, and they often differ because of different meanings and methods, not so much different facts or opinions. Since the measure of time is somewhat illusory, saying how old something that existed since the beginning of ‘time’ is difficult. We see back in time about 13.7 billion years, but ‘cosmic expansion’ allows light to have reached us from ‘before’ that point in time, which means that the universe is older than our observable universe. There are other reasons to suspect an older universe as well. None of this is too important to the present discussion.)
But here’s the thing. We thought everything was moving and/or expanding uniformly in all directions, as though a) the galaxies of the universe were like dots on a big, uniform rubber surface being stretched out so that all the dots grow more distant from each other and b) that that was pretty much the whole story at the largest scale.
Now there is evidence that there is a tugging effect on the known, visible universe. Galaxies are organized into clusters of galaxies, and these clusters are are all moving away from each other like they are supposed to, but they are ALSO moving towards something else. A place that is estimated to be beyond the known universe.
The picture above is the well known map of the background microwave radiation that comes from the origin of the universe and that has been subsequently altered by various relativistic effects. The pink blob is the place out there in the sky somewhere, but beyond the visible range, to which everything is being tugged, slightly.
What could possibly be out there, beyond the Universe, tugging on us?