Question

Enceladus, a small icy moon of Saturn, is known to harbor a global liquid water ocean beneath its icy crust. Scientists debate the primary source of heat required to maintain this liquid ocean.

Hypothesis 1
The ocean is maintained by tidal heating concentrated in Enceladus’s porous silicate core. As Enceladus follows its eccentric orbit around Saturn, the varying gravitational pull deforms the moon. This deformation causes friction within the porous rock of the core, heating the water that circulates through it via hydrothermal convection. Tidal dissipation within the ice shell itself is negligible because the ice is too rigid to generate sufficient heat.

Hypothesis 2
The heat is primarily generated by serpentinization, an exothermic chemical reaction. Cold, slightly acidic seawater from the ocean percolates deep into the silicate core, reacting with olivine ($\text{Mg}_2\text{SiO}_4$) to form serpentine minerals, magnetite, and hydrogen gas ($\text{H}_2$). This reaction continuously releases thermal energy. Gravitational tidal forces merely keep the fractures in the core open to allow seawater circulation but do not contribute directly to the heat generation.

Hypothesis 3
The liquid ocean is a transient feature sustained by the radioactive decay of long-lived isotopes ($^{40}\text{K}$, $^{232}\text{Th}$, $^{235}\text{U}$, and $^{238}\text{U}$) inside the core. While this radioactive heat generation has declined over geological time, it remains sufficient to prevent complete freezing because Enceladus's icy crust contains a thick, highly insulating layer of clathrate hydrates. This insulating layer prevents thermal energy from escaping into space at a rate faster than it is produced by isotopic decay.

Both Hypothesis 1 and Hypothesis 2 address the role of Saturn's gravitational tidal forces on Enceladus. Which of the following statements best describes how these two hypotheses differ in their core claims regarding the effect of these tidal forces?