There is still a lot about the formation of galaxies and star systems that we don&#x27;t know. The reason why we assume a lower <i>probability</i> for rocky planets in globular clusters is the general environment of the typical cluster: a small population of slow-burning early-generation stars with no appreciable interstellar dust clouds in between them.<p>If you compare that to low-metallicity stars in the galaxy proper, there are reasons why those might have planets that are not easily afforded to star systems located in globular clusters. Our galaxy is rich in dust and gas clouds that are also inhomogeneous. For example, a metal-poor star may be born out of a low-metal gas cloud and then attract a metal-rich dust disc later. These things are expected to happen a lot less often in globular clusters.