Titan in infrared

Titan puzzles scientists

On October 26, NASA’s Cassini-Huygens spacecraft swung by Titan at a distance of less than 1200 kilometers, the first of many fly-bys planned in the next few years.

Titan is Saturn’s largest moon and the second largest moon in the solar system, after Jupiter’s Ganymede. Titan is an enigma, having a massive atmosphere mainly of nitrogen with a pressure at the surface 1.6 times that of the Earth’s air at sea level. Its atmosphere also contains methane and at least nine other organic molecules. The methane is being continually destroyed by solar photolysis, which raises a further problem about its source of resupply. Unfortunately, the organic molecules in Titan’s atmosphere cause a global orange haze that has prevented us from seeing surface features. So, like the Magellan orbiter that allowed us to “see” the surface of Venus, Cassini is equipped with haze penetrating radar and infrared scanners.

On this first close flyby of Titan, Cassini’s radar mapped about one percent of Titan’s surface. The radar survey covered a strip 120 kilometers (75 miles) wide and 1,960 kilometers (1,200 miles) long in Titan’s northern hemisphere. Cassini also imaged Titan’s surface features through the haze using an infrared spectrometer. The result? The Dallas Morning News reported, “When the $3 billion Cassini spacecraft sailed past Titan three weeks ago, it was supposed to clear up many of the mysteries about Saturn’s largest moon. Instead, it has left scientists more befuddled.” The new Cassini images do not support previous theories about Saturn’s moon.

Titan in infrared
This image taken by Cassini's visual and infrared mapping spectrometer clearly shows surface features on Titan. It is a composite of false-color images taken at three infrared wavelengths: 2 microns (blue); 2.7 microns (red); and 5 microns (green). A methane cloud can be seen at the south pole (bottom of image). This picture was obtained as Cassini flew by Titan at altitudes ranging from 100,000 to 140,000 kilometers (88,000 to 63,000 miles), less than two hours before the spacecraft's closest approach. The inset picture shows the landing site of Cassini's piggybacked Huygens probe. Credit: NASA/JPL/University of Arizona

This report should be read in conjunction with my news item in June, which argues a different history of the solar system and, in particular, Saturn. It is time to reexamine the predictions I made there about Titan:

We should expect to see family traits amongst the members of the Saturnian family — including the departed Earth, Mars and Venus. For example, the moon Titan, which is larger than the planet Mercury, seems to be a close sibling of Venus, probably born from Saturn at about the same time. That Titan may be young is hinted at by its eccentric orbit, which cannot have persisted for billions of years. So we should be alert to similarities between Titan and Venus. It is already known that Titan has the densest atmosphere of any terrestrial planet, after Venus. That is a huge puzzle for scientists. After all, two of Jupiter’s moons, Ganymede and Callisto, have no atmosphere yet they are of similar size. So it would not be surprising if Titan had warm spots over the poles, like Venus. Titan also has a global layered haze like Venus. (Haze layers seem to be the condensed form that non-polar molecules take in an electrified atmosphere. They are quite distinct from the vertically moving clouds that polar molecules, like water, form). And just as Mars has a whiff of the Venusian atmosphere, with carbon dioxide and nitrogen as major constituents, we may expect to find that the Titan atmosphere has some of the smell of Venus about it. Both Venus’ and Titan’s atmospheres, being very young, will not yet be in equilibrium. So calculations about atmospheric constituents that assume equilibrium as a starting point will be wrong. The methane found in Titan’s atmosphere is quickly destroyed by sunlight so it has to be replenished. That has led to the suggestion that Titan must have a hydrocarbon ocean for the methane to have lasted for the conventional age of the solar system. However, radar, infrared and radio observations of Titan have not found signs of a hydrocarbon ocean. In fact one radar return was “of a type that we would expect to get back from Venus.” Titan is most likely a baby brother of Venus!

So what has been discovered in this first close flyby of Titan?

In New Scientist of November 6, 2004, Titan images add to moon’s mystery, Stephen Battersby reported:

The world got its first peek at the surface of Saturn’s moon Titan last week. The images were taken as NASA’s Cassini-Huygens spacecraft swept past the moon… The images show a landscape that is clearly still being shaped. Although Titan must have suffered numerous meteor impacts in the past, its surface today is largely crater-free. Somehow these scars must have been eroded or filled in.” “We are seeing a place that is alive, geologically speaking,” says Charles Elachi, head of the team running Cassini’s radar instrument.

Comment: That is precisely what was said about Venus when the Magellan Orbiter revealed that planet’s surface. It is only supposition that Titan’s surface is “still being shaped.” It is based on the belief that “Titan must have suffered numerous meteor impacts in the past” and therefore something must have occurred from within the moon to fill the craters. However, like Venus, there may have been no impact craters to fill. No one has witnessed a crater formed by a celestial impact. The relationship between craters and impacts is a hypothesis that has been accepted without considering another common form of cratering — that of electrical cratering. And electrical cratering has the virtue of explaining all of the curious features of planetary craters, particularly their circularity and tendency to occur in chains, with little disturbance of one crater by its neighbor.

We must therefore allow that Venus and Titan may both have new surfaces if planets and moons are not formed through accretion by impacts billions of years ago. The “befuddlement” and “mystery” may prove to be the result of an unquestioned belief in that hypothesis. Predictions based on that story have had no success in the space age. So we may be confident that planets did not accrete from a solar nebula.

Professor William H. McCrae wrote, “It is impossible to discover the origin of the solar system by observing it now, and working steadily backwards in time in order to infer the whole of its past history.” While agreeing with this statement, we must nevertheless make use of all available human observations of the sky before working forward from some hypothetical beginning. One of the greatest, albeit unheralded, surprises of the 21st century will be that the last chapter of the development of the solar system was witnessed and recorded by modern humans in prehistory. A forensic attitude to that evidence, as outlined in the earlier news item, can yield far more reliable predictions about what we will find in space than the purely hypothetical approach.

The New Scientist report continues:

Titan’s surface has thrown up other puzzles too. Infrared and radar images reveal bright “islands” surrounded by darker material, often crossed by long narrow features. These long lines – perhaps canyons, ridges or cracks – are up to 100 kilometres long but less than 200 metres wide. Just what these features are and how they formed is the focus of intense discussion.

Titan in infrared with close-up
>>These images show the surface of Titan at two different infrared wavelengths. They were captured by the visual and infrared mapping spectrometer onboard Cassini as the spacecraft flew by at an altitude of 1200 kilometers (745 miles) -- Cassini's closest approach yet to the hazy moon. The image on the right, taken at a wavelength of 2 microns, is the most detailed picture to date of the Titan's surface. It reveals complex landforms with sharp boundaries, which scientists are eager to further study. The image on the left was taken at a wavelength of 1 micron and shows approximately what a digital camera might see.Credit: NASA/JPL/University of Arizona

Unless they are artifacts of the imaging, the lines in the right hand image seem to be chains of craters. Venus too is covered with “long, narrow features” of constant width over very long distances, often featuring a chain of craters. They are identical to chains of craters on the Moon that are thought to be the result of fluidization of surface materials by venting of gases along presumed fault lines. But there are many problems associated with such explanations. The electrical explanation sees these narrow linear features formed by cosmic lightning, traveling across the surface. It explains the length of the channels, their constant width and on-channel cratering. We may expect many of the channels to have raised levees built up by ejecta from the trench. The channels may run uphill as well as down, discounting the channel having been cut by a flow of liquid.

Mars dunes
Martian dune field with blurred image on the left shows how the left hand infrared image of Titan could be a result of a similarly pitted or etched surface.
Diversity on Titan
This radar image of the surface of Saturn's moon Titan was acquired on October 26, 2004, when the Cassini spacecraft flew approximately 1,200 kilometers (745 miles) above the surface and acquired radar data for the first time. It reveals a complex geologic surface thought to be composed of icy materials and hydrocarbons. A wide variety of geologic terrain types can be seen on the image; brighter areas may correspond to rougher terrains and darker areas are thought to be smoother. A large dark circular feature is seen at the western (left) end of the image, but very few features resembling fresh impact craters are seen. This suggests that the surface is relatively young. Enigmatic sinuous bright linear features are visible, mainly cutting across dark areas. The image is about 150 kilometers (93 miles) wide and 250 kilometers (155 miles) long, and is centered at 50 N, 82 W in the northern hemisphere of Titan, over a region that has not yet been imaged optically. The smallest details seen on the image are about 300 meters (984 feet) across. Image credit: NASA/JPL

On November10 the NewScientist.com news service ran another report by Stephen Battersby titled: “Titan has no breaking waves.

Ideas about the nature of Saturn’s moon Titan are going through a total revolution as a result of new observations from the Cassini space probe. For many years, the prevailing view has been that Titan, hidden under perpetual cloud cover, was the only place in the solar system other than Earth whose surface was dominated by large liquid lakes or oceans up to three kilometres deep. But close-ups of the surface completely rule out such widespread liquid bodies, say scientists in the Cassini team.

The liquid was thought to be hydrocarbons such as ethane rather than water, because of Titan’s frigid -179˚C surface temperature. There had been hope that these bodies of liquid might harbour early stages in the development of biological molecules, and perhaps even simple forms of life. All that has changed, according to planetary scientist Robert Nelson of NASA-JPL. “That paradigm has been shaken to its foundations,” he said on Tuesday at the American Astronomical Society’s Division of Planetary Sciences annual meeting.

Dry as a bone

As recently as 2003, Earth-based radar observations provided strong evidence that as much as three-quarters of Titan’s surface was wet. But the new close-ups, while they only cover a portion of the surface, have completely ruled this out and make it highly unlikely that there is any liquid on the surface at all. Images taken by Cassini on 26 October, from a distance of just 1200 kilometres, failed to show any signs of the mirror-like reflections that would be expected from a liquid surface, even though the angles were right to see such reflections from at least four locations. Photometric profiles showed considerable variations across dark areas previously identified as possible lakes or seas. A liquid surface would have been more uniform. Radar imaging also showed variations in reflectivity. “There is no evidence of oceans,” says Carolyn Porco, Cassini imaging team leader. But project manager Dennis Matson cautions that “we’ve only seen part of Titan.” While extensive liquid bodies are ruled out, it is still possible there may be some much smaller bodies. “Perhaps more likely,” he suggests, “is a kind of slushy ice surface.”

Comment: The idea that Titan may have a considerable amount of low density liquids or ices came originally from calculations of its density. However, estimates of the composition of celestial bodies assume that we understand the real nature of gravity. We obviously don’t. So there is no reason to assume that the gravitational constant, ‘G,’ is the same for all bodies in the universe, particularly when it is the most elusive “constant” to measure on Earth. So we cannot be confident about the calculated ratio of rock to ices on Titan. But the presence of methane in Titan’s atmosphere seemed to require an ocean of liquid hydrocarbons as a reservoir that could provide a source of that gas lasting for the conventional age of the solar system. However, the radar image of Titan fits more closely (as we shall see) with some of those returned by the Magellan Orbiter from dry and rocky Venus. The methane puzzle has not been solved.

The report continues:

Suggestions of an active, dynamic surface on Titan are beginning to emerge. Not a single crater has been identified yet, which means the surface must be young and active. And there are some indications of volcanic activity produced by liquid water. Such cryovolcanism has been seen on other icy moons. One large circular feature, suspected of being a crater until closer examination showed it to be flat, closely resembles the pancake domes seen on Venus that are produced by magma welling up to produce a bubble that then slumps down to a nearly flat profile. On Titan, because of the temperatures, the features would be produced by flowing ice rather than molten rock. Other features resemble the lobes of some surface lava flows. But while the old view of Titan fades, scientists do not know what will take its place.

“We don’t understand what we’re looking at,” Matson says. “Titan is going to be a real challenge.”

Comment: The surprise about the lack of craters and Titan’s apparent “active, dynamic surface” mirror the comments made about Venus when radar images were first returned. The large flat circular feature on Titan does resemble the pancake domes seen on Venus.

Pancake domes on Venus
Pancake domes on Venus. They are about 25 km in diameter and up to 1 km high. Note the small central pits.

However, these domes were not formed by volcanic action. It would require an unacceptably large number of coincidences to produce such circularity in just one of these domes. The surface must be absolutely horizontal and the flow from the central vent must be perfectly even in all horizontal directions. But there are many domes on Venus.

In the ELECTRIC UNIVERSE® model, the domes are more simply explained as the raised blisters sometimes caused by cosmic lightning. Small-scale circular raised blisters have been found following a negative cloud-to-ground lightning strike to a lightning conductor cap. They are called ‘fulgamites.’ The shape of the mounds and the central crater seems to be due to the magnetic pinch effect. Even more telling, perhaps, is the rough concentric and radial pattern on top of the domes ‘ features also seen in photomicrographs of tiny fulgamites. A good further test of this hypothesis would be to determine if the surface around the domes is sunken. Fulgamites show this characteristic “borrow pit” effect where the material has been drawn inwards and up to form the raised blister. It is not something to be expected from a volcanic upwelling.

Inexplicably, in terms of the volcanic model, where two domes overlap the relief of the underlying dome does not disturb the overriding dome. This, and the chain formation seen above, is typical of electrical scarring in general where one crater is often centered on the rim of another with little disturbance of the existing crater. In cratering, the surface tends to be the cathode rather than the anode. With fulgamites, one mound often occurs on top of another as a result of multiple strokes within the lightning flash.

The branched sinuous features running diagonally across the image are also typical of filamentary discharges across a planetary surface. In places these channels will be seen to be a chain of pits. They are consistent with the linear features seen in the infrared image.

Cryovolcanism is the eruption of water or gas onto the surface of a planet or moon due to internal heating. It has only been observed on Triton, the largest moon of Neptune, during the flyby of Voyager 2. However, the plume seen on Triton may be of the same electrical nature as the plumes on Io, in which case it is not strictly cryovolcanism since it has nothing to do with internal heating of ices. Cryovolcanism on other icy moons has merely been inferred. The energetic events that shaped Titan’s surface ceased only thousands of years ago and probably included normal rock volcanism. Titan’s surface, like that of Venus, is young but no longer active.

So it seems that the images of Titan’s surface returned by Cassini so far are predictable based on forensic evidence that “we should be alert to similarities between Titan and Venus.” And “Titan is most likely a baby brother of Venus!”

This brings us to the other major puzzle about Titan — its atmosphere. Titan’s atmosphere is believed by many scientists to be similar to Earth’s early atmosphere, billions of years ago. Toby Owens, principal scientist at the Jet Propulsion Laboratory, said:

“What we’ve got is a very primitive atmosphere that has been preserved for 4.6 billion years. Titan gives us the chance for cosmic time travel . . . going back to the very earliest days of Earth when it had a similar atmosphere.”

Titan's nitrogen isotopes
This data is from Cassini's ion and neutral mass spectrometer, which detects charged and neutral particles in the atmosphere. The graph shows that the amount of light nitrogen in the atmosphere of Titan is much less than that around other planets. Scientists believe this nitrogen was lost over large geologic times scales for reasons that remain unknown. Credit: NASA/JPL/University of Michigan

From New Scientist, November 6:

“Titan appears to have lost much of its original atmosphere. The moon has an unusually high abundance of nitrogen-15, compared with the lighter isotope nitrogen-14. That could be explained if most of the atmosphere had evaporated into space, a process in which the nitrogen-14 would have escaped more easily than nitrogen-15. What could cause such a loss is unknown, but it would mean that Titan once had an atmosphere 40 times as thick as Earth’s – making it a dwarf version of a gas planet. “This bizarre world may be far more complex that we have begun to imagine,” says Larry Soderblom of the US Geological Survey in Flagstaff, Arizona.”
[Emphasis added]

Comment: Titan’s atmosphere is primitive, but not in the sense that it is 4.6 billion years old. Instead, there has not been time for young Titan to lose much atmosphere. The striking disparity in nitrogen isotopes is telling us something about the way planetary atmospheres are formed rather than how they evolve. Hannes Alfvén wrote in Evolution of the Solar System (NASA SP-345, 1976):

“..the Laplacian concept of a homogeneous gas disc provides the general background for most current speculations. The advent of magnetohydrodynamics about 25 years ago and experimental and theoretical progress in solar and magnetospheric physics have made this concept obsolete but this seems not yet to be fully understood.”

While acknowledging Alfvén’s point, it is possible to go a step further and invoke the electrical behavior of plasma, not just its magnetic behavior. There are several processes available in the plasma discharge model of planet birth that will have significant effects on planetary atmospheres, including that of new moons like Titan. The primary effect comes from the source and depth of the ejection from the flaring parent dwarf star or gas giant. Flaring red dwarf stars are extremely common and are an unexplained phenomenon in conventional stellar theory. They are the equivalent of a stellar lightning flash but they may produce the equivalent of 10,000 times as many x-rays as a comparably energetic flare on the Sun.

The x-rays are thought to be lethal to any life forms on planets near the dwarf star. However, the source of the x-rays in the ‘z-pinch’ effect and the position of the dwarf’s planets are probably not what is expected, using the Sun and our planetary system as a model. See “Other stars, other worlds, other life?” And it seems, from the geological record, that such flares do not sterilize a planet but may cause sudden extinctions and the appearance of new species. The episodic flaring and ejection of matter from the dwarf star would also account for the sedimentary layering of bodies, even those without atmospheres— like the Moon. On Earth it could account for subsequent burial and fossilization of the victims of such catastrophic electrical events.

How could this electric discharge model affect Titan’s atmosphere? To begin, there is sorting of chemical elements in the discharge according to their critical ionization velocity. Also isotopes will separate in the combined electric and magnetic fields of the cosmic plasma discharge. Lastly, the plasma gun effect (seen now ejecting material from Io into space) is known from laboratory tests to be a copious source of neutrons. The neutrons may be captured to form heavy isotopes and short-lived radioactive species. We find evidence of that in some meteorites that are also formed in this birth process. The variable combination of all of these effects suggest that it would be unlikely for any two bodies in the same ‘family’ to have the same initial atmospheres. Subsequent electrical interactions between planets and moons would serve to transfer surface materials and atmospheres, transmute elements, and further complicate the picture. That fits generally with the irregular elemental and isotopic signatures found in the atmospheres of our planetary system. For example, nitrogen in lunar soils is 10 times more abundant than one may expect from the concentrations of solar wind rare gases.

There are some other mechanisms that could also contribute to the lack of nitrogen-14 in Titan’s atmosphere. For example, nitrogen-14 can capture an electron to become carbon-14. Carbon-14 decays by very weak beta decay back to nitrogen-14, with a half-life of approximately 5,730 years. If the age of Titan’s atmosphere can be measured in thousands of years instead of billions, then a significant amount of nitrogen-14 may still be locked up on the surface as carbon-14.

Also, the intrinsic energy difference between the nitrogen molecule and the carbon monoxide molecule is quite small. In a hot plasma and the presence of a catalyst like iron, it has been demonstrated that nitrogen-14 molecules can convert to carbon monoxide molecules. Both carbon monoxide and carbon dioxide have been discovered in Titan’s atmosphere.

To suggest that “Titan once had an atmosphere 40 times as thick as Earth’s – making it a dwarf version of a gas planet,” only complicates the plainly impossible standard model of formation of the solar system. It does not explain why other large moons do not have substantial residual atmospheres. It seems far more plausible to suggest that Titan is a much newer moon than Jupiter”s Ganymede or Callisto. Titan simply hasn’t had time to lose its atmosphere — just as Saturn hasn’t had time to lose its rings following its last discharge.

The new Scientist report (11/6) also says:

Titan is thought to have a thick crust of water ice mixed with ammonia, but evidence is emerging that this may be covered by another layer of organic material. During the fly-by on 26 October, Cassini picked up microwaves from the surface that look like the thermal glow of hydrocarbon molecules. ‘Titan really is covered in organics,’ says radar team member Ralph Lorenz of the University of Arizona in Tucson. Scientists believe these hydrocarbons are created in the atmosphere when methane is broken down by sunlight and its components recombine into more complex molecules – a theory supported by the detection last week of benzene and acetylene high in the atmosphere.

Comment: If the Venusian surface were much cooler it would probably be covered in organic material too. There are many mysteries remaining about the atmosphere and clouds of that planet. There have been various claims that hydrocarbons exist in Venus’ atmosphere but there seems to be a reluctance to pursue such a possibility despite the fact that model atmospheres with sulfuric acid clouds cannot explain all of the features of the clouds on that planet. On Feb. 26, 1963, making known the results of the Mariner probe, Dr. Homer Newell of NASA announced that, in his judgment of those responsible for that part of the program, “Venus is enshrouded in an envelope of hydrocarbon gases and dust, 15 miles thick, 45 miles above the ground of the planet.” The conclusion was based on the work of L. D. Kaplan, who noted that lower cloud layers on Venus were homogeneous from top to bottom over a temperature range of 160C. His conclusion was that only compounds with multiple C-H (carbon-hydrogen) bonds have the same physical characteristics over such a temperature range.

Finally, there was news this week of the first hard evidence of methane on Mars. It raises the same issue as it does on Titan. What is the origin of the methane given that it is broken down by sunlight on Mars in a few hundred years? I would suggest that the methane on Mars and Titan had the same origin, since they interacted electrically with Saturn and Venus only thousands of years ago. Saturn has methane as a major constituent of its atmosphere, following hydrogen and helium. On Mars the methane was probably incorporated with surface material by ion implantation during a cosmic plasma discharge, which would possibly explain its patchy distribution and association with implanted hydrogen. The hydrogen discovered on Mars does not necessarily indicate the presence of subsurface water or ice, as is commonly thought.

Without doubt, many more surprises await scientists when the Huygens probe descends into Titan’s atmosphere and Cassini flies past Titan 44 more times over the next four years. The old paradigm is failing completely.

Wal Thornhill

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