chasma

noun2

1. •
   A long, narrow, steep-sided depression on a planet (often other than Earth), a moon, or another body in the Solar System.
2. •
   (no longer used, rare) An aurora.

   • Thus Cornelius Gemma, Professor of Medicine in Louvain, mentions them [the aurora borealis] under the name of chasma, as appearing in Brabant on the 13th February and 28th September, 1575. — 1814