Nomad Plan­ets

New re­search sug­gests that bil­lions of stars in our gal­axy have cap­tured rogue plan­ets that once roamed the voids be­tween stars.  The no­mad worlds, which were kicked out of the star sys­tems in which they formed, could oc­ca­sion­ally find a new home with a dif­fer­ent sun, as­tro­no­mers pro­pose. This could explain the ex­ist­ence of some plan­ets that or­bit sur­pris­ingly far from their stars, and even the ex­ist­ence of a double-plan­et sys­tem.