How are planets born? Scientists have long proposed that ice-covered pebbles are the seeds of planet formation. These icy solids are thought to drift toward the newborn star from the cold, outer reaches of the disk surrounding it. The theory predicts that, as these pebbles enter the warmer region closer to the star, they would release significant amounts of cold water vapor, delivering both water and solids to nascent planets.  

Now, the James Webb Space Telescope has witnessed this process in action, revealing the connection between water vapor in the inner disk and the drifting of icy pebbles from the outer disk. This finding opens exciting, new vistas into the study of rocky planet formation.