We’ve long thought that planets formed solely from the dust and gas that surrounds their young host stars, but that theory is now being challenged.

A new study published in the journal Astronomy & Astrophysics found that, more often than not, planetary systems actually outweigh the protoplanetary disks that they formed in — suggesting a severe lack of dust and gas around infant stars. The findings are causing researchers to question how planets accumulate so much mass, and wonder if t