is there an other galaxy or universe out there that we dont know of?

Question: is there an other galaxy or universe out there that we dont know of?
- Keywords:
  galaxies,
  universe
Asked by noah4-2forthebois to Duncan on 10 Nov 2017.
- Duncan McNicholl answered on 10 Nov 2017:
  
  I don’t know: if I did then we’d know about it!
  .
  To be honest, there’s loads of stuff we don’t know about so another galaxy or two seems pretty likely. A whole other universe is an interesting idea, but I don’t know if it could really happen.

Question: is there an other galaxy or universe out there that we dont know of?