Astronomy and Space
The geology of Titan, the largest moon of Saturn, is inferred from observations: Titan's density of 1.881 g/cm3 indicates that it is roughly 40–60% rock by mass, with the rest being water ice and other materials. It is differentiated into a rocky core, liquid water ocean, and an icy shell; the core and ocean may be partitioned by a layer of exotic high-pressure ices, and the icy shell may have a chemically distinct surface crust.
Alpha Vulpeculae.
21P/Giacobini–Zinner.
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