Super-Earths May Be Barren

A new study using computer models suggests that super-Earths-- worlds larger than Earth, but less than ten times as massive-- might not be good places for life to take hold.

The models imply that the extra mass fundamentally changes the formation of these worlds.  They tend to become one huge, dead rock instead of volcanically active, complex planets with mantles, hot, dynamic cores that produce magnetic fields, and plate tectonics.  Such activity, scientists say, is essential for the development of life.

Of course, that refers to native life.  Planets a few times as massive as Earth and chock full of natural resources might be ideal nodes for new branches of interstellar civilizations.  Even if the surface were unsuitable for the pioneering species, They could live comfortably in orbit while sending huge, tough machines to mine the planet.