Astronomers in Chile and Japan have for the first time seen part of the "cosmic web" of galaxies that permeates the known universe in a gigantic assembly some seven billion light-years from Earth.

Viewed through the world's most powerful telescopes, the discovery "is the first observation of such a prominent galaxy structure in the distant universe, providing further insight into the cosmic web and how it formed," the European Southern Observatory (ESO) said Tuesday in a statement.

The assembly of galaxies form filaments "millions of light years long and constitute the skeleton of the universe," it said.

"Galaxies gather around them, and immense galaxy clusters form at their intersections, lurking like giant spiders waiting for more matter to digest," it added.

The filaments are located about 6.7 billion light-years away and extend over at least 60 million light-years, the scientists said, adding the structure very likely stretches beyond the area they probed, warranting further observations.

"This is the first time that we have observed such a rich and prominent structure in the distant universe," said ESO's Masayuki Tanaka, who led the study.