Most planetary systems contain worlds larger than Earth but smaller than Neptune, and the low-density planets around one ...

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 ...

For years, astronomers have believed that water-rich planets could only form beyond a system’s “snow line,” the region where icy materials condense during planet formation. Yet a recent Nature study ...