For more than 200 years, astronomers thought that most of the stars in our galaxy had stellar companions. But a new study suggests the bulk of them are born alone and never have stellar company. Since planets are believed to be easier to form around single stars, the discovery could mean planets are more common as well. Conventional wisdom on double star systems, called binaries, goes as far back as the late 1700s. More sophisticated observations made in the 20th century seemed to confirm the numerical dominance of pairs. Stellar surveys found that more than half of all Sun-like stars...