Earth-mass planet resembles a mini-Neptune
Exoplanet 200 light-years away made mostly of gas, not rock
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2014/01/ag_exoplanet_feat.jpg?fit=860%2C460&ssl=1)
GASSY EARTH The planet KOI-314c, at right in this illustration, has about the same mass as Earth but is 60 percent larger. Another planet around the star (top) has the same diameter as KOI-314c but is made of rock, so it’s much heavier.
C. Pulliam & D. Aguilar/Harvard-Smithsonian Center for Astrophysics