Ithaca Chasma /ˈɪθəkə ˈkæzmə/ is a valley (graben) of Saturn's moon Tethys, named after the island of Ithaca, in Greece.[1] It is up to 100 km (62 mi) wide, 3–5 km (1.9–3.1 mi) deep and 2,000 km (1,200 mi) long, running approximately three-quarters of the way around Tethys' circumference, making it one of the longer valleys in the Solar System. Ithaca Chasma is approximately concentric with Odysseus crater.[2]
Ithaca Chasma may have originated when the global salt water ocean inside Tethys froze. This would have caused the surface to crack in order to accommodate the resulting increase in volume. Another hypothesis is that Ithaca Chasma is the outermost ring of the Odysseus impact basin; however the chasma is from 4 to 0.4 billion years old, making it slightly older than Odysseus.
- ^ USGS: Tethys: Ithaca Chasma.
- ^ Moore Schenk et al. 2004, pp. 424–30.