Hath in these last days spoken unto us by His Son, whom he hath appointed heir of all things, by whom also He made the worlds; Hebrews 1:2
"Io is the most volcanically active body in our solar system. The
colors of its surface are due to the different temperatures of various sulfur-containing compounds. Io’s volcanism is so intense that at today’s rates, it would have turned itself “inside out” more than 100 times in 4.6 billion years. Radioactivity can only make a small contribution to Io’s heat output, so uniformitarian scientists attribute most of Io’s present-day heat to tidal flexing. For a long time, creationists made much of the fact that simple models of tidal flexing could only produce a small fraction of Io’s observed heat output. This was an argument for youth because the only remaining option to explain Io’s warmth was leftover heat from its formation, which is only possible if Io is young.
But these previous calculations focused mainly on gravitational tugs
that Jupiter exerted on Io and the other Galilean moons. It was assumed
that the tugs the moons exerted on each other were not as important.
A
recent paper, however, claims that this inter-moon tidal heating can be
significant if the moons have subsurface liquid or magma oceans. If so,
previous tidal heating estimates for these moons may need to be
significantly revised.
So, present-day tidal flexing might be capable of explaining Io’s heat
output after all. This idea only works, though, if the presumed
subsurface oceans have just the right thicknesses. Until additional data or calculations shed more light on the issue, I would caution against dogmatism on this point.
Even so, Io still presents problems for evolutionists because its
erupting lavas are rich in magnesium. Geologists would say they are
ultramafic. But magnesium is a heavy element, and magnesium should have
settled deep into Io’s interior after billions of years. In that case,
lavas on Io should be depleted in magnesium, but this isn’t the case.
The idea that Io’s crust is ultramafic (magnesium-rich) seems inconsistent with the well-understood process of magmatic differentiation.
Heat flow on Io is sufficiently high that Io was expected to have
undergone partial melting and differentiation hundreds of times,
producing a low-density crust, depleted in heavy elements like
magnesium.
Some scientists think a completely molten core and a crystal-rich magma
ocean together could explain how Io’s crust could still be
magnesium-rich after billions of years. But both possibilities are disputed by other uniformitarian scientists.
Another option for evolutionists is to claim that Io’s volcanism was
much weaker in the past and only recently intensified. This would
explain the presence of magnesium in Io’s crust. But this would mean
that we’re lucky to be observing Io at such a special time in its
history.
ICR