Sandia National Laboratorie' Z machine has replicated the gravitational pressures on so-called "super-Earths" to determine which might maintain atmospheres that could support life. Astronomers believe that super-Earths -- collections of rocks up to eight times larger than Earth -- exist in the millions in our galaxy. "The question before us is whether any of these super planets are actually Earthlike, with active geological processes, atmospheres and magnetic fields," said Sandia physicist Joshua Townsend. The researchers found seven.