A steady fall of cometary ice, some scientists say, also helped to inundate the world and perhaps sowed organic molecules associated with life.

It is in the shadow of these deep walls that the cometary ice has apparently accumulated as a mixture of dirt and rock.

Today, to start a war over dilithium would make no more sense than to fight over cometary ice.

Other facilities high above Osquivel were designed to distill hydrogen out of cometary ice.

Moreover, astronomers increasingly see cometary ices as bearing the chemical precursors of life.

At first, all she saw was a huge lump of cometary ice, black-crusted over glacial blue gleaming.

Many particles did not form in the cold environment and locations where cometary ices condensed.

It would mean stripping the ship just to make the machines to mine and shape the cometary ice - years of work by any estimate.

Given the low density of cometary ice, almost all the fast-moving fragments detonate high in the stratosphere.

A moment later, a massive, smoking, black hulk of cometary ice floated into the main screen's view.