DOUBLE STARS
Reading edition
A large number of stars appear single, when viewed by the naked eye, but when seen through a powerful telescope, are seen to be, in reality, two stars which revolve round one another. Many thousands of such double stars are now known to exist; indeed, apparently single stars have been found, upon closer examination, to be composed of a group of four or five or more stars—so that the name “multiple stars” has been given to such groups. They are near one another in the astronomical use of that word—though they may actually be hundreds of thousands, or millions of miles apart. Many of these double stars seem to be quite separate from one another. Others appear to have some physical connection. Those which are known to form systems are known as binaries.