Astronomers think they know what goes into making a planetary system, namely dust - lots of it - swirling around a newly minted star. So it has been encouraging that astronomers have detected and even photographed dusty disks around many nearby stars, and they have inferred the presence of more than 100 planets around other stars. But until recently they had never seen dust and planets around the same stars. This month, astronomers said they had closed the loop. New observations by the Hubble Space Telescope and the Spitzer Space Telescope of dusty disks around nearby stars, they said, had...