September 6, 2022 | David F. Coppedge

How to Keep Titan Old Despite Evidence

Cassini’s finding of a mostly dry Titan falsified expectations.
But secularists refuse to give up on their beloved billions of years.

 

Falsification was supposed to judge theories. Confirmation is hard, philosophers in Karl Popper’s day knew, but falsification is easy. Find a fact that refutes a theory, and the theory is debunked. Firm believers in theories, though, find it really hard to accept falsification. When they multiply ad hoc scenarios to keep a prior belief alive, observers are under no obligation to give them credence.

Out of all the bodies in the solar system, planetary scientists were most assured that Saturn’s giant moon Titan had a global ocean on the surface. They based it on measurements from Voyagers 1 and 2 that Titan’s atmosphere, consisting mostly of nitrogen but with significant methane, was subject to an irreversible process. Solar radiation hitting the atmosphere in the 5% of time that Titan orbits outside Saturn’s protective magnetic field (JPL) would ionize methane (CH4) particles, converting them to ethane (C2H6) and other products. Ethane, being a stable liquid at Titan temperatures, should fall to the surface and accumulate, having nowhere else to go. Over billions of years, there should have been a global ocean up to a kilometer deep. Even if the breakdown of methane to ethane only occurred when Titan was outside Saturn’s magnetic field, it will still represent 225 million years of ethane accumulation.

The Cassini orbital tour (2004-2017), however, found otherwise. The mother ship observed some sizeable lakes at the poles, but no global ocean. The mission’s Huygens probe landed on icy sand moistened by methane, even though it was designed to float. Theory falsified, right?

We’ve reported a number of times about the distraught looks on scientists’ faces when no ocean was found. But one should never underestimate the dogmatism of scientists, and their creativity when it comes to finding rescue devices for favored theories.

The assumption they refuse to give up is billions of years. According to the ruling consensus, the solar system is 4.5 billion years old. We call this belief (qua Daniel 6:8) the Law of the Misdeeds and Perversions, because they treat it like a law that cannot be repealed. The belief has required numerous bandages to observations throughout the solar system. Hardly any planet or moon in the solar system looks that old: not Pluto, not Mercury, not Venus, not Enceladus, not Io or Europa, and certainly not Earth (e.g., Grand Canyon).

From time to time, a new paper arises trying to explain where Titan’s methane and ethane oceans went that should have been there. A new attempt by Tetsuya Tokano just appeared on Icarus, a leading journal of planetary science, on 30 August 2022, titled “Paleoclimate of Titan with hydrocarbon oceans and continents simulated by a global climate model.” So what does Takano say evaporated those missing oceans? Climate change!

Let’s give Tokano the podium and let him state his proposal to rescue Titan’s billions of years.

This study investigated how global-scale hydrocarbon oceans would change the paleoclimate of Titan depending on the ocean composition and presence of continents. The generic characteristics of Titan’s paleoclimate with oceans can be summarized as follows: Ethane-rich oceans behave like dry flat surface and cause a dry climate in the lower troposphere. However, the dryness refers to methane, not to ethane. Weak condensation of solid methane occurs in the upper troposphere, particularly at high latitudes. The atmospheric circulation resembles that predicted for hypothetically flat Titan under present conditions. Ethane-rich oceans dissolve only a few % of atmospheric nitrogen, so that the atmospheric pressure and temperature are similar to those on present Titan.

So far, this is purely hypothetical. “If” continents are present, and “if” the composition of oceans is methane or ethane, certain types of climate conditions would ensue, like wind.

Methane-rich oceans lower the atmospheric pressure and temperature as well as the sea surface temperature because of the dissolution of a larger amount of atmospheric nitrogen. The troposphere is very moist because of steady evaporation from the sea. Precipitation tends to be more frequent in summer but occurs perennially and globally, except in the polar region. Seasonal variation in N2 solubility slightly changes the atmospheric pressure globally but its impact on the weather is tiny. The meridional circulation is weak because of the small latitudinal pressure gradient. Continents embedded in ethane-rich oceans behave as obstacles that stand out from a flat surface. They cause some deflection of surface wind but has little influence on the thermodynamics and methane cycle of the troposphere. Continents embedded in methane-rich oceans are warmer than the ocean and thereby induce a sea breeze circulation in summer. This circulation carries moist maritime air to the continent and causes enhanced orographic precipitation on major windward slopes of continents. Seasonal precipitation over low-latitude continents surrounded by methane rich oceans may have been more conducive to continuing formation of fluvial valleys than the infrequent strong tropical precipitation in the present epoch. The formation of the observed numerous fluvial valleys in parts of Xanadu may have occurred under such conditions, supported by the desiccation of the ocean in Xanadu and Shangri-La due to a separation of this ocean from other oceans.

Huygens Probe descended to Titan on January 25, 2005. No ocean found.

Tetsuva has completely dodged the question of where the ethane went. It must have been there, the graphic above shows. It is produced continuously over billions of years. Why did it not accumulate into a global ocean half a kilometer deep or more? It was not observed as expected. Where did it go? All we find in the paper are speculations.

While the presence of methane-rich oceans in the past is consistent with the methane loss in the upper atmosphere, the presence of ethane-rich oceans in the past and its absence at present is a more speculative assumption considering Titan’s evolution. Hydrocarbon oceans should become more ethane enriched with time because methane is photochemically lost whereas condensed ethane from the atmosphere is deposited on the surface (Lunine et al., 1983). One possible explanation for the absence of ethane oceans at present is that the net ethane production rate in previous photochemistry models was greatly overestimated, e.g. due to non-inclusion of benzene (C6H6) in the photochemical path or an excessive eddy diffusion coefficient (Atreya et al., 2009). However, this alone would imply that ethane-rich oceans were even more unlikely in the past than at present. On the other hand, evaporation of ethane was measured upon landing of the Huygens Probe (Niemann et al., 2005) and ethane was spectroscopically identified in one of Titan’s lakes (Brown et al., 2008). Thus, ethane condensation is likely to have taken place.

He can’t get away from the fact that, over billions of years, there should have been an ethane ocean. Where did it go?

One possible scenario is the occurrence of clathrate decomposition and massive cryovolcanism within the past 1 Gyr (Tobie et al., 2006), which substantially increased the porosity of the crust (Mousis and Schmitt, 2008). This may have caused entire percolation of ethane-rich oceans that might have existed 1 Gyr BP and would explain the absence of such oceans at present. Occurrence of freezing of the ocean is diagnosed by comparing the sea surface temperature with the liquidus temperature Tliq and solidus temperature Tsol. The model uses Tliq = 85 K and Tsol = 78 K in C2H6-rich oceans (80 % C2H6, 20 % CH4) and Tliq = 78.7 K and Tsol = 72.4 K in CH4-rich oceans (20 % C2H6, 80 % CH4) after Hofgartner and Lunine (2013). However, such low sea temperatures never occurred in the model under any assumed conditions. Therefore, the model does not treat ice formation, floating or sinking. Furthermore, possible stratification of Titan’s seas in the presence of multiple hydrocarbons (Stevenson and Potter, 1986, Steckloff et al., 2020) cannot be treated in the framework of this model since the slab ocean model is intrinsically unstratified.

So how did all that ethane sink into the interior of Titan with very little left on the surface?

This discussion of the long-term climate evolution is so far based on speculations only and calls for a more systematic and quantitative study considering changes in the sea volume, sea compostion, distribution of continents, ocean currents, solar luminosity etc. Lastly, it is necessary to stress that Titan’s paleoclimate with hydrocarbon paleooceans as a whole remains speculative despite all the arguments mentioned in the introduction. Other climate evolution paths via episodes of methane depletion (Lorenz et al., 1997, Charnay et al., 2014) and subsequent methane snowball (Tokano and Lorenz, 2021) might also be possible.

He’s just speculating. So now, 17 years after the Huygens Probe landed on icy sand with a thud, they still have no answers. How convenient to just bury the problem out of sight!

Titan’s paleoclimate in the presence of hydrocarbon oceans and continents is likely to have been more complex than the climate of globally ocean-covered Titan or globally ocean-free Titan. Studies of the evolution of Titan’s climate may need to consider the configuration of continents and its possible long-term variation, in addition to previously considered variations in solar luminosity and methane inventory.

Keep the funds flowing, NASA: maybe the proposed Dragonfly mission can figure this out. While they are at it, maybe they can explain why Titan still has an atmosphere if it is rapidly losing its mass. A 2012 paper, well into the Cassini mission, estimated that 7 metric tons of atmospheric mass is lost per Earth day (24 hours).

See also how Harvard dodged the question in 2016 in an article, “Titan’s Missing Ethane”:

Estimated 8.46E17 kg or 1.37E6 km3 of C2H6 have been produced on Titan since accretion. The Titan surface reservoirs of ethane are lakes and craters, of estimated volume of 50,000 km3 and 61,000 km3, respectively. As these are smaller than the total volume of liquid ethane produced in the course of Titan’s history, the excess may be stored in the subsurface of the crust, made primarily of water ice.

The ethane measured in the sparse polar lakes was thus about 4% of what was predicted for the whole moon. They immediately jumped from that problem to whether Titan has life. That’s a classic sidestep maneuver.

A paper in 2009 said that methane hydrolysis should have produced a liquid ethane layer of “several hundred meters over geologic time.” The post-Huygens paper tried to answer “the Case of the Missing Ethane.” Even with geological tricks, they could only get it down to 10 meters globally averaged.

We gave Dr Tokano plenty of space to try to explain what happened to the missing ethane oceans. All we got were (1) distractions about climate change, (2) dodging the issue, (3) escape tricks (saying the ethane might have sunk out of sight under the crust), and (4) appeals to futureware. We think people should know that they still have no answer.

It would sure be nice to see planetary scientists show some humility, and admit they were wrong.

The simple solution to all this dodging and speculation? Give up the billions of years. So easy. But they will never do this, because Darwin needs the time.

 

 

 

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