Double planet arguing that Jupiter is a double star is "not" analogous to arguing Pluto-Charon is a double dwarf planet. The problem is that Jupiter is not even a star, or even a brown dwarf, and due to its low mass it is unable to achieve any form of fusion. Isaac Asimov suggested a distinction between planet–moon and double-planet structures based in part on what he called a "tug-of-war" value, which does not consider their relative sizes. This quantity is simply the ratio of the force exerted on the smaller body by the larger (primary) body to the force exerted on the
The Secret of the Ninth Planet Plutonians dead, the danger to the solar system is past. Burl sees then the people of other planets and of other stars coming together in peace and mutual understanding. The book was reviewed by “When the power of the sun becomes noticeably diminished, young Burl Denning and his expedition take off in an anti-gravitational ship to discover the cause and its location. After a dizzying tour of all the planets, they realize that the trouble springs from Pluto, a belligerent planet which is trying to usurp the life-giving power which the sun gives earth. Making an alliance with the friendly