But the company has faced a barrage of unfavorable publicity in recent months, including the fallout from allegations that it bribed officials in Mexico in order to smooth the way for store expansion, and criticism about its global sourcing practices after its clothing was found in a Bangladesh factory where more than 100 workers died in a fire last year.

WSJ: Wal-Mart Ad Campaign Touts 'American Success Story'

Such expansion would stretch space and smooth matter, while leaving small density variations that show up in the CMB.

BBC: The observable Universe and beyond