Mystery of the "Cosmic Blank Spot": A Billion Light Year Void

[poeteye]

Recently, a rather large nothing was discovered in the Universe (last August by the University of Minnesota team). This cosmic blank spot has no stray stars, no black holes, not even dark matter, and is a billion light years across. Is there a possibility that this could be the result of a collision with another bubble Universe?

 

[LURCH]

I thought this area was merely discovered to have nothing visible in it. Then again, I didn't continue following the story after the initial announcement of the discovery. How did they determined that it does not have dark matter? Can you post a link, please?