What’s going on with Saturn’s largest moon? Observations show lakes are appearing and disappearing which means the lakes are shallow and the liquid hydrocarbons in them are moving around. These lakes predominantly contain methane and ethane. In 2004, new dark areas was discovered in Arrakis Planitia near the south. These lakes have shrunk considerably in a span of 44 months.
A new paper and photo…Lake Ontario Lacus, which was discovered on the south pole, its shoreline has shrunk by 5.5 to 7 miles. Estimates of shrinkage is a bit tricky, while it’s not practical to measure these lakes directly, estimates show how much Arrakis gained and lost as a proxy which are based on estimates from 2004, containing the methane-carrying capacity cloud system where the cloudburst must have declined 2.4 to 14 cm of methane rain into the Arrakis basin (upper limit 4.2 m). This yields estimates that between 24 to 140 km3 of liquid was lost at Arrakis in 4 years from a combination of evaporation and infiltration; probably similar amounts at Ontario.
Interesting to note, the northern lakes in Titan have not declined between observations. This makes it even more interesting to watch what the “methane cycle” does to the southern and northern lakes as the seasons change and more sunlight hits the north.
Another thing to watch for is the lake bottom not being dark, as might be expected from sedimentation of hydrocarbons. Either some sort of wave action cleansed the bottom as the shoreline retreated, or any sediments are light colored. The authors favor the sediments being light-colored latter, saying that “bright organic condensates may be deposited within the lakes and exposed as the liquid level drops (Barnes et al., 2009).” This view is strengthened by the fact that the Cassini orbiter’s cameras saw numerous dark features in the south in 2004-2005, but light material as Ontario retreated. It is not possible to know from albedo (reflected brightness) alone the composition of the bright sediments.
One can take a look back in history in all of this, in 1981 when Voyager I made its visit, scientists discovered an irreversible erosion of atmospheric methane was precipitating hydrocarbons onto the surface (especially ethane, which doesn’t have a way to get back into the atmosphere), scientists expected to find, over the course of 4.5 billion years, an accumulation of half a kilometer or more of liquid ethane in a global ocean.
The prediction of liquid ethane based on an assumption of Titan being 4.5 billion years old was later falsified in a specular way by the Cassini observations! In fact, the Huygens probe had been designed to float on that ocean predicted by scientists but that failed to come true. Instead, scientists discovered on Titan to have paltry accumulations of liquid in scattered lakes near the poles, while the equatorial regions are largely covered in icy sand dunes!
Now the sediments are bright, which would be surprising in itself, so one asks, “is there enough sediment to account for 4.5 billion years of deposition?” In addition, Titan, the largest moon with the greatest gravitational attraction, accounts for only a few craters (three to five) after all that time. You may be asking with these observations, could there been processes go on for billions of years? Many scientists are forced into a particular timescale, evolution happened slowly and gradually with the planets and stars. So what evolution sounds best at is when the evidence is speculated upon an unseen. These type of explanations had been invoked for the falsifications done by the probes on Titan.
For example, somehow the ethane seeped into the interior where no one can find it; maybe the interior has a methane reservoir that erupts through cryovolcanoes, replenishing the atmosphere; maybe this, maybe that. If these scientists stick to the observations being discovered and draw reasonable conclusions from data alone, they would have to conclude that there are severe upper limits on how long Titan has been acting this way! The phenomena happening on Titan verifies, a Creator namely God!