Esta é " Jangada " de Stephen Baxter.
The novel is an elaborated version of his 1989 short story of the same title, Raft. The story follows a group of humans who have accidentally entered an alternate universe where the gravitational force is far stronger than our own, a "billion" times as strong. Planets do not exist, as they would immediately collapse under their own gravity; stars are only a mile across and have extremely brief life-spans, becoming cooled kernels a hundred yards wide with a surface gravity of five g. Human bodies possess a "respectable" gravity field in and of themselves. "Gravitic chemistry" also exists, where gravity is the dominant force on an atomic scale.