Harry C. Stubbs
[In his The End of the World,] Branley speculates on a number of possible ways in which the earth will eventually become uninhabitable. He has been only moderately successful in digesting a very complex subject…. He has not managed to avoid being dogmatic. He has also followed a couple of standard mistakes. It is about four million tons of mass, not of hydrogen, which the sun's fusion reaction consumes (the hydrogen loses only about a third of one percent of its mass in the reaction, so over a billion tons of hydrogen are used). The Roche limit value is that for a satellite of equal density with its primary; for a less dense body like our own moon the value would be larger. Granting that the distinction is beyond the grasp of the intended readers, why not mention only the correct figure? I am dubious about the statement that the early earth was covered by deep layers of ice, and I take strong objection to the claim that carbon dioxide would act as a "mirror" to reflect solar radiation back into space. It is generally credited with enhancing the greenhouse effect, keeping the heat in. The speculations themselves are interesting, but I would have been happier if their underlying reasons had been brought out more clearly. It seems to me that this might have provided more stimulation for readers to investigate the pertinent sciences more deeply.
Harry C. Stubbs, "'The End of the World'," in Appraisal: Science Books for Young People (copyright © 1975 by the Children's Science Book Review Committee), Vol. 8, No. 2, Spring, 1975, p. 10.