[Jason]

(CNN) -- Scientists at NASA have discovered a nearly invisible ring around Saturn -- one so large that it would take 1 billion Earths to fill it.

The ring's orbit is tilted 27 degrees from the planet's main ring plane. The bulk of it starts about 3.7 million miles (6 million km) away from the planet and extends outward another 7.4 million miles (12 million km).

Its diameter is equivalent to 300 Saturns lined up side to side. And its entire volume can hold one billion Earths, NASA Jet Propulsion Laboratory said late Tuesday.

"This is one supersized ring," said Anne Verbiscer, an astronomer at the University of Virginia in Charlottesville.

Verbiscer and two others are authors of a paper about the discovery published Wednesday in the journal Nature.

The obvious question: Why did it take scientists so long to discover something so massive?

Scientists discover massive ring around Saturn - CNN.com