Centuries of astronomical observation and technological advances have revealed a lot about the Universe we all call home, but it’s also raised plenty of new questions. Researchers have crunched a lot of numbers to try to make sense of the Big Bang and the billions of years that followed, but something just isn’t adding up.

Put simply, calculations of the amount of mass that was blasted into space after the Big Bang suggest that there’s a lot more matter out there somewhere that we haven’t seen and can’t detect. But why? That’s something NASA’s Chandra X-ray Observatory is doing its best to answer.

As NASA explains in a new blog post, the missing matter may have lumped together into massive “strands” of gas that are strung about in intergalactic space. We’d never be able to see that gas with a visible light telescope, but Chandra’s instruments may have begun to unravel that mystery. The work was published in the Astrophysical Journal.

If the Universe’s missing mass can be explained by vast ribbons of gas in deep space it would solve a lot of burning questions astronomers still have about the beginnings of the Universe.

Recently, the X-ray telescope was used to examine what is believed to be evidence of these huge gas ribbons near a distant quasar. By examining specific wavelengths to isolate the signals coming from the gas and dim the overpowering energy of the quasar itself, the researchers say they spotted 17 possible strands of gas lying between Earth and the quasar some 3.5 billion light years away.

“We were thrilled that we were able to track down some of this missing matter” co-author Randall Smith said in a statement. “In the future we can apply this same method to other quasar data to confirm that this long-standing mystery has at last been cracked.”