Enceladus, Previous Speedster – AAS Nova

Three of Saturn’s moons — Tethys, Enceladus and Mimas — as seen from NASA’s Cassini spacecraft [image credit: NASA/JPL]

Enceladus is in a 2:1 resonance with a moon named Dione, but Tethys – another major moon of Saturn – orbits between them and is in a 1:2 resonance with Mimas, whose orbit lies inside that of Enceladus. So the order of proximity to the planet is Mimas, Enceladus, Tethys, Dione. The study looks at how the Enceladus-Dione part of this unusual set-up could have come into being. Talking of speed, all four moons orbit their very large planet in less than three days (Mimas in less than one day).
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Enceladus, one of Saturn’s moons, is currently being tugged around and heated up by another moon named Dione, says AAS Nova.

How the two ended up in this arrangement is a mystery, since to get there, Enceladus must have avoided getting caught up in a resonance with another moon named Tethys.

A recent article offers a possible explanation: Enceladus may have blitzed over to its current position in a short-lived burst of speed.

Dynamic Moons
We typically imagine that moons circle their host planets with clockwork regularity, meaning that they precisely trace out the same path at the same speed for all time. However, true reality cannot be described by a system composed of rigid gears.

Jupiter’s ocean moons raise tides on each other

Credit: NASA [click on image to enlarge]

The effects of relative proximity between these large moons seem to have been underrated. Not forgetting that Jupiter does have a big effect on Io, the closest Galilean moon to it.
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Jupiter’s “ocean world” moons may have strong gravitational effects on each other, raising big tides in each others’ subsurface seas, a new study suggests [Space.com reporting].

Surprisingly, these moon-moon tidal forces might generate more heat in the satellites’ oceans than the gravitational tugs of giant Jupiter, study team members found.

“That’s kind of interesting, because Jupiter is the biggest mass in that system, so its tidal forces are much bigger than one moon on another,” lead author Hamish Hay, who performed the work while at the University of Arizona’s Lunar and Planetary Laboratory, said in a statement.

A proof of De Rop’s long-term lunar cycle (1799 anomalistic years)

Credit: NASA

The idea is to validate Belgian astronomer Willy de Rop’s 1971 calculations, which can be found here.

From our 2016 post discussing his paper, De Rop’s long-term lunar cycle:

De Rop’s basic premise is that there’s a correlation between the so-called ‘lunar wobble’ period and the anomalistic year.
His paper contains a geometric proof, and the final numbers are:
300 lunar wobbles in 1799 anomalistic years (the lunar wobble is known to repeat in just under 6 years).

To see what the lunar wobble is, refer to the paper. Essentially it’s when the number of lunar apsidal and nodal cycles in the period sums to 1. For more information, please refer to that post.

Research reveals possibly active tectonic system on the Moon

Image credit: naturalnavigator.com

We’re told: ‘They refer to what they’ve found as ANTS, for Active Nearside Tectonic System’, which is ‘a mysterious system of tectonic features (ridges and faults) on the lunar nearside, unrelated to both lava-filled basins and other young faults that crisscross the highlands.’ Tectonic activity on one side only sounds a bit unlikely somehow, but what about tidal disturbance from Earth? We know it works the other way round: the Moon causes tides on Earth. Of course the Moon is tidally locked to Earth, hence the term ‘nearside’.
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Researchers have discovered a system of ridges spread across the nearside of the Moon topped with freshly exposed boulders, reports Phys.org.

The ridges could be evidence of active lunar tectonic processes, the researchers say, possibly the echo of a long-ago impact that nearly tore the Moon apart.

“There’s this assumption that the Moon is long dead, but we keep finding that that’s not the case,” said Peter Schultz, a professor in Brown University’s Department of Earth, Environmental and Planetary Sciences and co-author of the research, which is published in the journal Geology.

“From this paper it appears that the Moon may still be creaking and cracking—potentially in the present day—and we can see the evidence on these ridges.”

Galactic cosmic rays affect Titan’s atmosphere

Saturn seen across a sea of methane on Titan by Huygens probe 2005

Some extracts from an article at Phys.org, bypassing the chemistry details. A research professor commented: “The process could be universal”. Interesting…
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Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn.

The team found a chemical footprint in Titan’s atmosphere indicating that cosmic rays coming from outside the Solar System affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules.

This is the first observational confirmation of such processes, and impacts the understanding of the intriguing environment of Titan.

The giant planets, the lunar year and the Sun

Jupiter-Saturn-Earth orbits chart

This was just about to go live when a new idea involving the Sun cropped up, now added to the original. The source data is from NASA JPL as usual.

From our 2015 de Vries post we saw that the 2503 year period, which the numbers were based on, consisted of 85 Saturn and 211 Jupiter orbits [see chart on the right].

Taking Saturn’s orbit period, and using JPL’s planetary data we find:
10755.7 days * 85 = 914234.5 days

The lunar year is 13 lunar orbits of Earth:
27.321582 days * 13 = 355.18056 days

914234.5 / 355.18056 = 2573.9992 (2574) = 13 * 198 lunar years

Number of beats of Saturn and the lunar year = 2574 – 85 = 2489 in 2503 years.
2503 – 2489 = 14
Number of Jose cycles in 2503 years = 14 (= 126 Jupiter-Saturn conjunctions, i.e. 9 J-S * 14).

Therefore the difference per Jose cycle between ‘Saturn-lunar year’ beats and Earth years is exactly one.

Before Caledonia presents: Torhouse Stone Circle

[4mins.25 secs. video]

This is considered to be one of the best preserved ancient stone monuments in Britain, although research into it seems to have been minimal. It can be found near Wigtown in the far south-west of Scotland.

Note the specific solar alignments of the three central stones, and the lunar significance of its circle of nineteen megaliths – thought to represent the lunar nodal cycle of 18.6 years, according to the commentary (or possibly the 19 year Metonic cycle – or both?).

The Metonic cycle is described as ‘a period of almost exactly 19 years that is nearly a common multiple of the solar year and the synodic (lunar) month.’

A question from Ned Nikolov

This looks self-explanatory, so here’s the graphic…

[click on image to enlarge]

Neptune’s moons locked in ‘dance of avoidance’

Neptune Moon Dance: This animation illustrates how the odd orbits of Neptune’s inner moons Naiad and Thalassa enable them to avoid each other as they race around the planet. (courtesy: JPL)

Well, this is fun. Need we say more?

Even by the wild standards of the outer solar system, the strange orbits that carry Neptune’s two innermost moons are unprecedented, according to newly published research.

Orbital dynamics experts are calling it a “dance of avoidance” performed by the tiny moons Naiad and Thalassa, says Space Newsfeed.

The two are true partners, orbiting only about 1,150 miles (1,850 kilometers) apart.

Sun science has a bright future on the moon

Credit: reference.com

There are many reasons NASA is pursuing the Artemis mission to land astronauts on the moon by 2024: It’s a crucial way to study the moon itself and to pave a safe path to Mars, says Phys.org.

But it’s also a great place to learn more about protecting Earth, which is just one part of the larger Sun-Earth system.

Heliophysicists—scientists who study the Sun and its influence on Earth—will also be sending up their own NASA missions as part of Artemis. Their goal is to better understand the complex space environment surrounding our planet, much of which is driven by our Sun.

Wilson and Sidorenkov – A Luni-Solar Connection to Weather and Climate III: Sub-Centennial Time Scales

Thanks to Ian Wilson for introducing us to his new paper, which is part three of the planned four-part series. The paper can be downloaded from The General Science Journal here. Abstract below.

Abstract

The best way to study the changes in the climate “forcings” that impact the Earth’s mean atmospheric temperature is to look at the first difference of the time series of the world-mean temperature, rather than the time series itself.

Therefore, if the Perigean New/Full Moon cycles were to act as a forcing upon the Earth’s atmospheric temperature, you would expect to see the natural periodicities of this tidal forcing clearly imprinted upon the time rate of change of the world’s mean temperature.

Using both the adopted mean orbital periods of the Moon, as well as calculated algorithms based upon published ephemerides, this paper shows that the Perigean New/Full moon tidal cycles exhibit two dominant periodicities on decadal time scales.

Ian Wilson: Solving this week’s trade winds puzzle

Credit: Ian Wilson

Researcher and Talkshop contributor Ian Wilson writes:

The Easterly Trade Winds Over the Equatorial Pacific Ocean Have Disappeared Over the Last 5 Days or So!

If you want to find out why, go to his own blog post: here.
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The trail of clues goes on from there!

Lunar connection: the Saros, nodal and apsidal cycles

Image credit: naturalnavigator.com

The contention here is that in the time taken for 14 lunar nodal cycles, the difference between the number of Saros eclipse cycles and lunar apsidal cycles (i.e the number of ‘beats’ of those two periods) is exactly 15.

Since 15-14 = 1, this period of 260.585 tropical years might itself be considered a cycle. It is just over 9 Inex eclipse cycles (260.5 years) of 358 synodic months each, by definition.

Although it’s hard to find references to ~260 years as a possible climate and/or planetary period, there are a few for the half period i.e. 130 years, for example here.

The Metonic cycle in long-term lunar harmonics

Image credit: interactivestars.com

In 2015 this post discussed long-term lunar precession from an apsidal, or anomalistic, standpoint.

We saw that all the numbers related to an exact number (339) of Metonic cycles (19 tropical years each, as discussed below).

Here we show the equivalent from a nodal, or draconic, standpoint.

Again, all the numbers relate to an exact number (337 this time) of Metonic cycles.

Origin of massive methane reservoir identified

Natural gas flare {credit: Wikipedia]

As we already knew from elsewhere in the solar system, fossils are not essential for the production of methane aka natural gas. Only two ingredients are needed, one being water, as explained below.

New research from Woods Hole Oceanographic Institution (WHOI) published Aug. 19, 2019, in the Proceedings of the National Academy of Science provides evidence of the formation and abundance of abiotic methane—methane formed by chemical reactions that don’t involve organic matter—on Earth and shows how the gases could have a similar origin on other planets and moons, even those no longer home to liquid water.

Researchers had long noticed methane released from deep-sea vents, says Phys.org. But while the gas is plentiful in the atmosphere where it’s produced by living things, the source of methane at the seafloor was a mystery.

New study traces Io’s volcanic tides

Credit: NASA [click on image to enlarge]

In a 2015 Talkshop post we found a resonant period of 486.5 days for the inner three of the four Galilean moons of Jupiter: Io, Europa and Ganymede. Here the researchers find a period of 480-484 days, which clearly looks very much the same as our period, linked to recurring volcanic activity. They find this ‘surprising’, but the repeating alignments of these moons with Jupiter – at the same time interval – look to be more than a coincidence.

Hundreds of volcanoes pockmark the surface of Io, the third largest of Jupiter’s 78 known moons, and the only body in our solar system other than Earth where widespread volcanism can be observed, says Phys.org.

The source of the moon’s inner heat is radically different than Earth’s, making the moon a unique system to investigate volcanism.

A new study in the AGU journal Geophysical Research Letters finds Io’s most powerful, persistent volcano, Loki Patera, brightens on a similar timescale to slight perturbations in Io’s orbit caused by Jupiter’s other moons, which repeat on an approximately 500-Earth-day cycle.

Moonquakes rattle the Moon as it shrinks like a raisin

View from the Moon [credit: NASA]

Moons don’t generally ‘shrink’, so what’s going on here? The abstract of the research paper speaks of compressional stresses, but the only potential source of compression would seem to be the Earth. It’s known that ‘the crust on the far side is a lot thicker than it is on the near side’, as discussed here.

The moon is still tectonically active, like Earth, generating moonquakes as our planet creates earthquakes, a new study based on Apollo mission data found.

These moonquakes likely happen because the moon is quivering as it shrinks, researchers added.

On Earth, tectonic activity, such as earthquakes and volcanism, results from shuffling of the crust’s tectonic plates driven by the churning of the planet’s molten interior, says Charles Quoi at Space.com.

However, the moon is much smaller than Earth and therefore largely cooled off long ago, so one might not expect much, if any, tectonic activity.

Lunar evections and the Saros cycle

Credit: Matthew Zimmerman @ English Wikipedia

The Saros cycle can be used to predict eclipses of the Sun and Moon, and is usually defined as 223 lunar synodic months, or about 11 days over 18 years.

But there are a few other lunar-related periods which can used to arrive at 223.

One Saros cycle can be said to be the difference between the number of:
— anomalistic months and full moon cycles (239 – 16)
— draconic months and draconic years (242 – 19)
— tropical months and tropical years (241 – 18)

That may be fairly well known, but then there are the lunar evections.

Lunar-planetary links to the Lucas sequence – part 3 and summary

Earth from the Moon [image credit: NASA]

Part 3

To recap, the Lucas series starts: 2, 1, 3, 4, 7, 11, 18, 29 … (adding the last two numbers each time to find the next number in the series).

Note: for clarity, the three parts of this mini-series should be read in order (links below).

Since Part 2 showed that 7 Jupiter-Saturn conjunctions (J-S) = 11 * 13 lunar tropical years (LTY), and from Part 1 we know that 363 LTY = 353 Earth tropical years (TY), these numbers of occurrences can be integrated by applying another multiple of 13:
363 = 3*11*11 LTY
therefore
353 * 13 TY = 3*11*11*13 LTY = 3*7*11 J-S

7 and 11 are Lucas numbers.
13 is a Fibonacci number.
3 belongs to both series.

Saturn’s moon Titan has eerie lakes on its surface just like Earth

Saturn seen across a sea of methane on Titan by Huygens probe 2005

Not sure they mean Earth also has eerie lakes – apart from Lake Erie perhaps. Titan, billed here by a researcher as ‘the most interesting moon in the solar system’, has some observed similarities with Earth, plus some quirks of its own.

There’s one other place in the solar system where liquid rains, evaporates, and seeps into the surface to create deep lakes: Saturn’s moon Titan, says Tech Times.

In this alien world, the Earth-like hydrologic cycle does not take place with water, but with liquid methane and ethane. In Titan’s ultra-cold environment, these gases behave just like water.

Two new papers published in the journal Nature Astronomy detailed the findings of the concluded Cassini mission, particularly the details on Titan’s lakes and their composition.