The popular announcement, picked up by all the mass media, involved an article published in the journal Nature and a news release by the American Astronomical Society. Both reported that there are more planets than stars in our galaxy.
More planets than stars: This is a concept to which the public could truly relate. Everyone knows what a planet is, since we live on one. Everyone also knows what stars are. In our science-deficient culture – insecure about the astrophysics realm, with its endless terms like Hubble flow and angular power spectrum – here was a headline for the unwashed masses. The reason astronomers yawned was simply because we’ve known this for nearly 20 years. Ever since Peter Van de Camp’s 1960s announcements of planets orbiting nearby stars, we realized that planets must be common rather than rare.
Prior to that, in the 1950s, there were two competing ideas about how planets are born: Some thought that a star has to pass very close to another and gravitationally pull off a string of material, like pizza cheese. This star stuff would then condense into a row of balls and, voilà! You get a system of planets. If this were the case, planets would be very rare occurrences, since close stellar encounters are unusual. The competing view was that, as any star forms from a condensing nebula, the leftover dusty gas contracts here and there, like lumps in pudding, into a series of planets. If this were the case, then planets must be common.