AROUND A MINOR G-TYPE STAR fairly far out toward one edge of a medium-sized galaxy the planets of that star swung as usual, just as they had for billions of years, under the influence of a slightly modified inverse square law that shaped the space around them.  Three of them were big enough, as planets go, to be noticeable; the rest were mere pebbles, concealed in the fiery skirts of the primary or lost in the black outer reaches of space.  All of them, as is always the case, were infected with that oddity of distorted entropy called life; in the cases of the third and fourth planets their surface temperatures cycled around the freezing point of hydrogen monoxide - in consequence they had developed life forms similar enough to permit a degree of social contact.