Saturn Rescues Earth: Outer Planet Wonders
How Saturn saved the Earth, and other news from the ringed planet, its family, and other bodies in the outer solar system.
It takes much more than a habitable zone to give life a stable platform. It requires cooperative neighbors, too. Computer models, reported by Jeff Hecht on New Scientist, found out that Saturn, even though it’s about 800 million miles away from Earth, could have yanked the Earth out of its life zone.
Earth’s orbit is so nearly circular that its distance from the sun only varies between 147 and 152 million kilometres, or around 2 per cent about the average. Moving Saturn’s orbit just 10 percent closer in would disrupt that by creating a resonance – essentially a periodic tug – that would stretch out the Earth’s orbit by tens of millions of kilometres. That would result in the Earth spending part of each year outside the habitable zone, the ring around the sun where temperatures are right for liquid water.
Tilting Saturn’s orbit would also stretch out Earth’s orbit. According to a simple model that did not include other inner planets, the greater the tilt, the more the elongation increased. Adding Venus and Mars to the model stabilised the orbits of all three planets, but the elongation nonetheless rose as Saturn’s orbit got more tilted. Pilat-Lohinger says a 20-degree tilt would bring the innermost part of Earth’s orbit closer to the sun than Venus.
The model created at the University of Vienna also showed that Saturn also has the power to jolt Earth out of the solar system altogether. This would seem to imply, since such disruptions do not occur, that Saturn’s position is finely tuned for life on Earth. This must also be true for Jupiter, which is closer and more massive.
Other Saturn News
Hit-and-run ID’d: The interloper that smashed into Saturn’s rings in 1983 and left waves that persist to this day appears to have been one or more Centaurs, small bodies that are part asteroid and part comet. “The rings may not settle down any time soon,” the article on New Scientist says. “There is evidence that similar patterns in other rings are hundreds of years old.” Ring impacts are destructive processes.
Titan’s magic island: An island disappears and reappears in Titan’s large lake Kraken Mare. PhysOrg says the Cassini scientists are still trying to figure out what’s going on, and how deep the lake is. Next chance for a look with the radar mapper is in January 2015.
Watch a dune: Theories about the formation of Titan’s equatorial sand dunes is the subject of another article on PhysOrg. Scientists in Paris have proposed a new model involving wind speed, particle density, atmospheric density and sediment supply.
The researchers have shown that, contrary to accepted theory, the dunes on Titan could not have been formed from an entirely mobile bed of sediment. Their orientation suggests that they have formed over a non-erodable substrate consisting of either solid material or sediment with grains too large to be transported, obtaining sufficient material for their growth from a local source of sediment. In this case, they would be aligned with the resultant wind direction, maintaining a constant orientation and shape over several hundred kilometers. This correlates well with observations of the actual dunes.
The mechanism comports with formation mechanisms seen on Mars and Earth, the team claims. They say that it takes extreme conditions to get winds strong enough to form the dunes. These winds must occur during the Titanian equinoxes, they believe.
Enceladus snow cone: Warm fluff is at the heart of Enceladus, New Scientist claims. The crash you hear is the fall of another paradigm:
In the cold of space, a tiny moon is keeping warm with a fluffy heart. Enceladus, the pipsqueak of a world renowned for shooting huge watery plumes into space as it orbits Saturn, has a secret – a core that contradicts everything we thought we knew about the structure of planetary bodies.
“Enceladus isn’t following the rules,” a group meeting of the Geological Society of America claimed at a meeting Oct. 19. Like most differentiated bodies, Enceladus should have a crust of ice, a watery mantle, and a core of solid rock, but “A stiff rocky core would not flex enough to generate the heat necessary to melt the ice or explain the jets.” When James Roberts modeled the core with snow-cone-like material, it had the ability to flex and generate the heat needed to keep the geysers going. Quotable quote:
“Enceladus has been surprising us all along,” Roberts says. “You’d think something the size of the North Sea would be cold and dead, but the Cassini spacecraft has been observing activity since it arrived.“
Cassini team scientist Hunter Waite wonders if we are living at a special time to see Enceladus so active. The rest of the article drifted into data-free speculations about life.
Other Far-Out News
Uranus storms: Amateur astronomers are thrilled, and scientists are puzzled, at huge storms observed in the cloud bands of Uranus recently. UC Berkeley reports that amateurs are glad to see activity on the otherwise bland surface of the planet. Embarrassed scientists are looking a little amateurish at their inability to explain it:
“This type of activity would have been expected in 2007, when Uranus’s once-every-42-year equinox occurred and the sun shined directly on the equator,” noted co-investigator Heidi Hammel of the Association of Universities for Research in Astronomy. “But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody’s guess.”
The team who wrote this up in a paper shrugged, “These unexpected observations remind us keenly of how little we understand about atmospheric dynamics in outer planet atmospheres.” National Geographic‘s headline reads, “Newfound Mega-Storms on Uranus Pose Planetary Puzzle.” Scientists usually pride themselves on prediction and explanation, but the article says, “one thing is for sure, this busy weather on Uranus has caught scientists completely off-guard.” From a UCB scientist: “There definitely is a lot of dynamic activity in Uranus’s atmosphere, and we have no idea why.”
Miranda rights: Have scientists figured out the origin of Uranus’ weird little moon, Miranda? The old theory was that multiple impacts broke apart pieces that coalesced into its odd surface of cratered smooth plains with sudden “coronae” of completely different texture. Two new hypotheses appeared recently. GSA Today offers this one by Hammond and Barr: “Global resurfacing of Uranus’s moon Miranda by convection.” Icarus tries another by Beddingfield, Burr and Emery: “Fault geometries on Uranus’ satellite Miranda: Implications for internal structure and heat flow.” Someone else may want to check whether these hypotheses are congruent, complementary, or contradictory. It appears that both depend on tidal heating. Neither one mentions the old impact hypothesis; what happened to it?
Atlas unshrugged: New maps of Vesta and Enceladus were released. Space.com published the new Vesta atlas, “the best geologic look ever,” which Astrobiology Magazine says shows a history of large impacts. PhysOrg says that 100,000 ice blocks were mapped on Enceladus, and 101 geyser vents pinpointed. No source for the heat was mentioned, but the geysers are a “source of interest” and the ice blocks a “source of wonder,” mapped “in the hopes of determining just how they got there.” Multiple hypotheses were offered.
Tidbits: A paper in Icarus tries to place upper limits on the space erosion and cosmic ray exposure (CRE) dates of stony meteorites. The upper limits are in the hundred-million-year range – not billions. It appears that surface erosion destroys evidence of cosmic ray exposure over time, except for iron meteorites, which erode more slowly; author David P. Rubincam notes, “Iron meteoroids erode too slowly to fix meaningful upper limits on CRE ages.” Meanwhile, Space.com offered an article with “fun facts and information” about larger tidbits: asteroids.
Philae mignon: Nature celebrated the short-lived success of the Rosetta spacecraft’s Philae lander on Comet 67P, noting that its 64-hour activity period, though shorter than planned, was sufficient to provide 90% of what its scientists had hoped for. Sadie Jones on The Conversation likened the mission’s nail-biting adventure to this generation’s moon landing. Of special interest is that some organic material was detected in the comet’s atmosphere, or coma (Space.com); Nature says the team is scouring the data for evidence of chirality. The Rosetta orbiter will continue to gather science data for up to two more years, and maybe—just maybe—the kiss of increasing sunlight as the comet nears perihelion will once again wake up the sleeping beauty.
These news stories are enough to arouse wonder. Wonder at the beauty and variety of the bodies in our solar system. Wonder at the intelligence of our space engineers to get to these far-away places. And wonder at the inability of our greatest planetary scientists to understand what they see. When you hear scientists, caught “completely off guard,” admitting how little they understand, and they have “no idea why” things are happening because they “contradict accepted theory,” leaving explanations that “are anyone’s guess,” you are hearing re-runs of what they said about every body that our intelligently-designed spacecraft have visited.
We often describe the difference between data gathering and explanation. You see it in stark contrast here. We love the thrill of discovery; we warn against the fallibility of secular explanations. Scientists like to build models, which is fine; but models are simulations of reality, not reality itself. Most models are vastly oversimplified. Some incorporate ad hoc conditions to try to match the observations (such as Enceladus having a “snow cone” core). All the secular models assume billions of years, but then they have to face the music: Saturn’s eroding rings, Enceladus’s geysers, and stony meteorites eroding away faster than billions of years will allow. They hope we won’t remember the old models, or notice that the new models contradict what was taught in the textbooks.
Some atheists and secularists find fulfillment in the search. To them, it doesn’t matter if answers are always in future tense; this is better than just saying “God did it,” in their straw man characterization of the creation position (“how” God did things is a motivation for science, and no creationist thinks God hand-crafted every object in the solar system). But in any other job, would you get paid for just looking busy, and never delivering the goods? Check out our Solar System category of entries. You will find, over and over again, that planetary scientists are stunned, surprised, and stupified, left dumbfloundering over the latest observations. In our opinion, much of their confusion comes from never questioning the A.S.S. Start with different initial conditions (like a far more recent intelligent design, shall we suggest), and maybe some lights would turn on.