The galaxy is littered with planetary systems vastly different from ours. In the solar system, the planet closest to the Sun—Mercury, with an orbit of 88 days—is also the smallest. But NASA’s Kepler spacecraft has discovered thousands of systems full of very large planets—called super-Earths—in very small orbits that zip around their host star several times every 10 days.
Click here for original story, Gravitational forces in protoplanetary disks may push super-Earths close to their stars
Source: Phys.org