Scientists don't expect to find comets. They've mostly ruled that out given that the dimming has taken place for several decades or more. However, the spectral data could at least point them in the right direction. If there's consistent spectral dimming, it would point to a solid object like a planet. More uneven dimming, meanwhile, could point to dust or gas as the culprit.

A definitive answer isn't all that likely, at least not without extended analysis. With that said, just having a general idea of what's involved could be enough to shoot down wilder theories and narrow the focus. That, in turn, could improve humanity's overall understanding of the cosmos and prepare for the next time researchers spot something they can't immediately explain.