Saturn

Background
Dirty Rings
Origin of Rings
Age of Rings
Saturn's Rotation Slowing
Water in Magnetosphere
X-Ray Reflection


Background
Saturn is the most distant planet that can readily be observed from the Earth. But most of what was known before the arrival of the Cassini probe was based on data returned by Voyager 1 and 2 which flew by some twenty-three years ago. Saturn is the second most massive planet behind Jupiter, 95 versus 318 times as massive as the Earth. Since its surface is masked by clouds, the estimate of its rotational period was made by both Voyager probes via measurements of fluctuations in its magnetic field.

Currently its interior is hypothesized to be 95 % hydrogen, the inner portion of which is thought to be in an electrically conductive state. It is also thought to include significant helium with smaller quantities of the other elements in ‘solar‘ proportions. The presence of a rocky-iron core, similar to that thought to be at the heart of Jupiter has yet to be confirmed, but a long term analysis of the trajectory of the Cassini orbiter should make this possible.

Saturn’s most spectacular aspect is the system of more than a thousand rings which encircle it in its equatorial plane. They were photographed by the Voyager probes, revealing this beautiful complexity. The sizes of the particles in the ring are thought to range from microns to house-sized bodies, but no probe, not even Cassini, which arrived in Saturn orbit in July, 2004, has passed close enough to resolve them. It has resolved a number of larger bodies within the rings, but they are considered satellites.  Both Voyager probes, nine months apart, photographed a number of transient spoke-like shadows superimposed on the rings, inplying the presence of a rapidly changing source of particles from the planet, which lasted for a significant interval of time.  Cassini has imaged the same spokes, implying their longer-term nature.

Dirty Rings
The Cassini probe has the potential to answer many questions concerning Saturn because of the length of its mission and the complement of instruments it carries. Cassini data has already revealed several unexpected findings about the Saturnian system. Although it has confirmed the previously held notion that the rings comprise primarily water ice, infrared and ultraviolet spectrometers indicate that a considerable fraction of the inner-most rings contain refractory elements, or more simply put, dirt. This is illustrated in a false-color image of the rings shown at the right. This finding has compounded the question of the origin of the rings, a problem which already existed when they were thought to be pure water. If, as currently believed, Saturn is a gaseous body of hydrogen and helium, the water comprising the rings and satellites cannot be from the planet. It has been suggested that one or more comets might have been captured and broken up by the tidal force of Saturn, forming the rings. The difficulty in this argument is illustrated by the presence of a number of small satellites amid the rings. These did not break up, because their internal cohesiveness is much stronger that the tidal force exerted on them by Saturn. The breaking up of bodies within the Roche limit only applies to theoretical bodies that have no cohesiveness. This leads to the second possibility, that two comets collided within Saturn’s tidal stability (Roche) limit producing billions of tiny particles, which formed the rings. The probability of such a collision within the Roche limit is infinitesimal. Based on the new data, the comets not only had to have incorporated considerable ‘dirt,’ but it is impossible to explain how the dirt made its way to the inner rings and the water to the outer rings.

The ‘gas giant’ paradigm suffers the same problem at Jupiter and Saturn. All the satellites and rings which surround them are composed primarily of water, while the planets are thought to contain only minuscule amounts of it. It is from this untenable assumption that a myriad of current problems arise.

Origin of Rings
My catastrophism paradigm provides an exquisitely simple solution, which eliminates all of these difficulties. (See my papers on Jupiter and the Cosmogony of the Solar System at http://uncommonresearch.blogs.com/ackermanarchive). That is, that the giant planets are composed primarily of methane gas hydrates, structures of water molecules that are known to form at low temperatures and high pressure, exactly the conditions within the giant planets. Moreover, I maintain that asteroids from within our system or from interstellar space are continually impacting the giant planets, just as stated in all the textbooks. A massive one impacted Jupiter 6,000 years ago, producing proto-Venus, the Galilean moons, the GRS, the zonal jets which encircle the planet, indeed, the energy released as a result of that impact (10^43 ergs) shaped the solar system we observe today. The longevity of the atmospheric features is due to the ignition of nuclear conflagrations in the craters, from which gases and heat continue to stream for millennia.

Prior to that impact a lesser energy body impacted Saturn. This impact resulted in the ejection of a relatively modest amount of material (equivalent to a 100 km sphere), primarily water, into a low Saturn orbit, well within its Roche limit. This ejection may have occurred in two stages, as in the case of the Jupiter impact. The first stage would have been the initial ‘splash’ at the time of the impact and the second a sustained jet of hot gases emanating from the nuclear burning initiated in the crater, which may still be occuring on Saturn, as evidenced by the spokes of material superimposed on the rings.

Due to the tidal force of Saturn this ejecta never coalesced. The rings formed from the water which comprises the bulk of the planet in the form of frozen methane gas hydrates. This scenario also explains the fact that the dirty rings lie closest to the planet. Because of their greater masses, the refractory elements imbedded in the methane gas hydrates, the same heavy elements from which proto-Venus accreted in the wake of the Jupiter impact, were not ejected with velocities as high as the lighter elements such as hydrogen, oxygen, carbon and nitrogen because of their greater weight. Some of the satellites were probably ejected by the initial impact and some coated by the jet material in the subsequent period.

Age of Rings
The question of the origin of the rings also involves their age. In the current uniformitarian paradigm, everything in the solar system is thought to have been in its current state for 4.5 billion years. Some scientists still hold to the notion that the rings were formed at the time Saturn accreted, but fortunately most realize that this is impossible. The rings are now acknowledged to be ‘new,’ which in the uniformitarian context implies a minimum age of 100 million years! No matter what ad hoc ideas are invented to try and make this true for the rings, they cannot be anywhere near this age. Hubble and Cassini observations have already found evidence of ongoing dissipation of the innermost and outermost rings, by different processes.

While acknowledging this dissipation, some scientists are now proposing a wild scheme in which the material lost is continually being replaced by particles subliming from the larger satellites. They are hoping by this process to be able to ‘extend’ the age of the rings to 100 million years. Why the obsession with a great age for the rings? If they cannot be primordial, then what is the difference what their age is?

In my scenario the only time constraint is that they be very young. Asteroids are impacting the giant planets all the time, producing large ‘spots’, such as those that were observed by Earth-based telescopes in 1990 and 1994 on Saturn. In keeping with the notion that Jupiter’s Great Red Spot is a storm, these were interpreted as earth-sized ‘storms’ on Saturn, which amazed scientists at their sudden appearance.  I maintain that these spots are the tops of columns of hot gases rising from giant impact craters in their methane gas hydrate surfaces.  Because the Great White Spot of 1990 was intensely observed, its evolution into zonal jets or wind bands to its north and south can be seen in the inset photos surrounding the fully developed stage. This illustrates how the rising column of hot gases from the enormous impact on Jupiter 6000 years ago, manifested as the GRS, drives its zonal jets.

In a serendipitous coincidence, both Voyager 1 and 2 photographed what was possibly material in the process of being ejected from Saturn in the aftermath of such an impact. This was manifested in the form of transient, dark, radial shadows, called spokes, superimposed on the rings, as shown in the figure. The fact that these spokes were observed by both Voyager probes nine months apart indicates a situation existed on Saturn similar to that on Jupiter in the aftermath of the high energy impact 6000 years ago. Once the burning of methane is initiated in the impact crater the outward flow of hot gases can continue for extended periods of time. On Jupiter the ejection of a jet of hot gases continued for some 6,000 years. I maintain that the spokes were caused by material being ejected from such a crater on the surface of Saturn.  Cassini has now photographed the same phenomenon, proving that at long-term source on the planet is still ejecting mass into the surrounding space.

Saturn’s Rotation Slowing
A closely related mystery revealed by Cassini concerns the rotation period of Saturn. This was measured using the same technique as the voyager probes. But Cassini measured the Saturn ‘day’ to be !0 hours, 45 minutes, and 45 seconds. This is a full six minutes, or one percent, longer than measured by the Voyager 1 and 2. In the current paradigm, there is no prosaic explanation for such a change in a massive planet’s rotation. In the V/A paradigm this is easily explained, particularly in light of the evidence that Jupiter’s period has changed from about one hour to almost ten hours as a result of the impact on it 6,000 years ago. I maintain that this increase in the rotational period is due to the mass and angular momentum currently being ejected into space from the recent impacts.

Water in Magnetosphere
Another Cassini measurement reinforces the notion that water is continually being ejected from the planet. The CHEMS instrument has already yielded data indicating the plasma in Saturn’s magnetosphere consists mostly of hydrogen and oxygen ions and molecular ions derived from water. This is important data because the lifetime of ions in the magnetosphere is quite short compared to the entire ring system. They must be continually supplied from other sources. The primary source in the current paradigm is thought to be sublimation from Saturn’s icy moons. I maintain the source is either a jet of hot gases from a recent crater on the surface of Saturn or the rings. If the latter, this implies a very limited age for the rings.

X-ray Reflection
In April 2003, NASAs Chandra probe took X-ray images of Saturn, and planetary scientists are puzzled by the results. See "X-Ray Emission from Saturn", by J.-U. Ness and S. Wolk published in Astronomy & Astrophysics, 2004. Their X-ray image, on the right, shows that the X-rays are concentrated in the anti-solar direction as would be consistent with reflection from a solid sphere. The spectrum, or distribution of the wavelengths of the X-rays from Saturn, was found to be very similar to that of X-rays from the Sun. The 90 megawatts of Saturn’s X-radiation is similar to the intensity obtained from Jupiter and indicates that they reflect energy fifty times more efficiently than the solid surface of the Moon. This high reflectivity and its angular distribution suggests a combination of specular reflection and diffusion in the dense atmosphere. The fact that the X-ray energy from the rings of Saturn is insignificant compared with the body of the planet was a great surprise to the scientists involved. Perhaps the atmospheric pressure is great enough to allow methane gas hydrates to exist on the surface of Saturn and enhance the X-ray reflection. It will be interesting to see how scientists explain this reflection in terms of the old gas giant paradigm.