Artist's concept of  the Galaxy String

Giant Galaxy String Defies Models of How Universe Evolved |  Wide-field telescope observations from the CTIO Blanco 4-meter telescope of the remote and therefore early Universe, looking back to a time when it was a fifth of its present age (redshift = 2.38), have revealed an enormous string of galaxies about 300 million light-years long. This new structure defies current models of how the Universe evolved, which can’t explain how a string this big could have formed so early.

For more information, see the NASA/Goddard Press release