Science: Little Inhabited Stars

When astronomers (or science-fiction writers) speculate about nonearthly kinds of life, they generally think of strange beings existing on planets revolving around a star that is at the proper distance to keep them reasonably warm. Astronomer Harlow Shapley, former head of the Harvard Observatory, has figured that there are probably 100,000 life-bearing planets in the Milky Way galaxy. Last week Shapley suggested that the universe may contain another class of celestial bodies that could sustain life. They are neither planets nor true stars, and are somewhere in between the two in size—perhaps 100 times bigger than the planet Jupiter or 1/100th...