As telescopes have become more powerful, it’s turned out our solar system is not the only game in town: There are millions of other planets out there in the galaxy. But we’re still teasing out clues ...

Astronomers have found thousands of exoplanets around single stars, but few around binary stars—even though both types of stars are equally common. Physicists can now explain the dearth. Of the more ...

Planets larger than Earth but smaller than Neptune are the most common kind in the galaxy, but because our solar system lacks such a planet, scientists don’t know much about how they form. Astronomers ...