When the wild turmoil had subsided, when the debris no longer sang about us, when the upheaved masses had either fallen again or had spun beyond Europa's gravitation to crash on indifferent Jupiter, the pass had vanished. Mountain and vacuum hemmed us into a prison.
Both of us were slightly stunned by the concussion, although the thin atmosphere transmitted a strangely high-pitched sound instead of the resounding b-o-o-m one would have heard on the Earth. When my head stopped ringing, I looked around for Gogrol, and saw him at last seven or eight hundred feet up the slope of the mountain. Anger surged in me; I seized a stone from the margin of the pool, and flung it viciously at him. One can throw amazing distances on small worlds like Europa; I watched the missile raise dust at his very
