Something outside, tugging at our universe..

Scientists have found streams of matter ,
for whose movement there is no explanation within our observable universe.
These are caused neither by the well known expansion of the universe itself (expansion of space itself since the Big Bang, 14 Billion years ago), nor by any detectable mass of matter within  our observable universe.
The only explanation for these streams of matter thus is that there is something "significantly large" OUTSIDE of our known universe causing these streams.
Exactly what this might be is not known yet, but this discovery has opened up speculation that our universe might be part of a significantly larger structure, or only one among a number of other universes.