Planets that orbit at very comparable distances from their stars may jockey for place whereas nonetheless remaining in a broadly secure configuration for billions of years – lengthy sufficient to be noticed by astronomers. Such star programs is likely to be so unlikely that they may solely be created artificially, by superior alien civilisations.
Most planets have their orbits to themselves, however orbital mechanics permits for worlds to be shut sufficient to successfully share an orbit, forcing them right into a helter-skelter dance the place they …
Source: www.newscientist.com