Astronomers see stars slinging comets at Earth for the first time

The distance from the Oort cloud to the interior of the Solar System, and two of the nearest stars, is measured in astronomical units. The scale is logarithmic; each indicated distance is ten times farther out than the previous distance. The red arrow indicates the location of the space probe Voyager 1, which will reach the Oort cloud in about 300 years [credit: NASA / JPL-Caltech]

Note that the Oort Cloud referred to in the article, although often discussed as though it exists, has to date never been directly observed, perhaps due to its supposed great distance from Earth.
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Stars and comets make unlikely dance partners, says Live Science.

Their gravitational partnership is one that astronomers have long suspected but have never seen — until now. For the first time, a Polish group has identified two nearby stars that seem to have plucked up their icy partners, swinging them into orbits around our sun.

The astronomers found the stellar duo after studying the movements of over 600 stars that came within 13 light-years of the sun. The new findings validate a theory born more than a half-century ago, and in doing so have also shown just how rare these stellar dances can be.

Out on the far edge of the solar system, hanging like wallflowers around the planetary dance floor, is the Oort Cloud.

Stardust in the Antarctic snow: Iron-60 discovery in the Antarctic provides information on the environment of solar system

Image credit: extremetech.com

A 2016 article in Astronomy Now reported:
“Scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans.

The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr. Anton Wallner from The Australian National University (ANU).

“We were very surprised that there was debris clearly spread across 1.5 million years,” said Dr. Wallner, a nuclear physicist in the ANU Research School of Physics and Engineering. “It suggests there were a series of supernovae, one after another.

“It’s an interesting coincidence that they correspond with when the Earth cooled and moved from the Pliocene into the Pleistocene period.” [bold added]

In August this year a new find was reported…
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The rare isotope iron-60 is created in massive stellar explosions, says ScienceDaily. Only a very small amount of this isotope reaches the earth from distant stars.

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.

Voyager 2’s trip to interstellar space deepens some mysteries beyond our solar system

The two Voyager space probes, launched in 1977, are still delivering tales of the unexpected.

The boundary region between the sun’s sphere of influence and the broader Milky Way galaxy is complicated indeed.

Humanity’s second taste of interstellar space may have raised more questions than it answered, writes Mike Wall @ Space.com.

NASA’s Voyager 2 spacecraft popped free of the heliosphere — the huge bubble of charged particles that the sun blows around itself — on Nov. 5, 2018, more than six years after the probe’s pioneering twin, Voyager 1, did the same.

The mission team has now had some time to take stock of Voyager 2’s exit, which occurred in the heliosphere’s southern hemisphere (as opposed to Voyager 1, which departed in the northern hemisphere).

In a series of five papers published online today (Nov. 4) in the journal Nature Astronomy, the researchers reported the measurements made by the probe as it entered interstellar space.

Planet Nine: How we’ll find the Solar System’s missing planet

The predicted ninth planet has so far proved elusive, with searches of 50 per cent of the sky in the range where it ‘should’ be having turned up nothing. But planetary theorists Mike Brown and Konstantin Batygin insist the evidence shows they are on the right track. Others talk of broken glass and fingerprints – shades of Sherlock Holmes.

Beyond Neptune, a handful of small worlds are moving in harmony.

Astronomers think they might be dancing to the tune of a third world lurking in the darkness, one that’s four times bigger than Earth and significant enough to be named our Solar System’s ninth planet.

Now they think they know exactly where to look for it, says Science Focus.

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.

Site of biggest ever meteorite collision in the UK discovered

Hebridean islands of Scotland

So it is believed at least. Researchers say a more detailed underwater survey is needed.

Evidence for the ancient, 1.2 billion years old, meteorite strike, was first discovered in 2008 near Ullapool, NW Scotland by scientists from Oxford and Aberdeen Universities.

The thickness and extent of the debris deposit they found suggested the impact crater—made by a meteorite estimated at 1km wide—was close to the coast, but its precise location remained a mystery.

In a paper published today in Journal of the Geological Society, a team led by Dr. Ken Amor from the Department of Earth Sciences at Oxford University, show how they have identified the crater location 15-20km west of a remote part of the Scottish coastline.

The Sun follows the rhythm of the planets, says German research institute

Main solar system planets [image credit: Wikipedia]

No s**t Sherlock! Numerous independent researchers, some featured at the Talkshop, have been working along such lines for years with little apparent recognition and even a certain amount of negative reaction (like this), let’s say.

H/T Miles Mathis

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HZDR press release of May 27, 2019: New study corroborates the influence of planetary tidal forces on solar activity.

One of the big questions in solar physics is why the Sun’s activity follows a regular cycle of 11 years. Researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), an independent German research institute, now present new findings, indicating that the tidal forces of Venus, Earth and Jupiter influence the solar magnetic field, thus governing the solar cycle.

Why Phi? – the Saturn-Uranus connection

Distances not to scale.

This is an easy data table to interpret.

The Uranus orbits are all Fibonacci numbers, and the synodic conjunctions are all a 3* multiple of Fibonacci numbers.
[Fibonacci series starts: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, …etc.]

In addition, the difference between the two is always a Lucas number. And that’s it for Saturn-Uranus, which would make for a very short blog post.

But it’s possible to go further.

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.

Dust ring discovered in Mercury’s orbit

Image credit: Wikipedia

The next step is to find the source(s) of the dust, with as yet undetected asteroids thought to be the leading suspects.

Two dusty discoveries may shake up our understanding of the inner solar system, says Fox News.

Mercury shares its supertight orbit with a big ring of wandering dust, a recent study suggests. And a cloud of as-yet-undiscovered asteroids likely gave rise to a similar halo in Venus’ neighborhood, another new paper concludes.

Scientists track deep history of planets’ motions, and effects on Earth’s climate

Planetary theory lives on, even if it now has to nod towards trace gases in the atmosphere to be in fashion with the times.

Scientists have long posited that periodic swings in Earth’s climate are driven by cyclic changes in the distribution of sunlight reaching our surface, says Phys.org.

This is due to cyclic changes in how our planet spins on its axis, the ellipticity of its orbit, and its orientation toward the sun—overlapping cycles caused by subtle gravitational interplays with other planets, as the bodies whirl around the sun and by each other like gyrating hula-hoops.

But planetary paths change over time, and that can change the cycles’ lengths. This has made it challenging for scientists to untangle what drove many ancient climate shifts.

Waves in Saturn’s rings give precise measurement of planet’s rotation rate

Saturn from the Cassini orbiter [image credit: NASA]

This has been a tricky problem for years as explained below, and now appears to have been resolved. But whether that’s the end of the story remains to be seen.

Saturn’s distinctive rings were observed in unprecedented detail by NASA’s Cassini spacecraft, and scientists have now used those observations to probe the interior of the giant planet and obtain the first precise determination of its rotation rate, reports Phys.org.

The length of a day on Saturn, according to their calculations, is 10 hours 33 minutes and 38 seconds.

Does it snow on Mars?

Clouds on Mars [image credit: NASA]

H/T Discover Magazine

This wasn’t the first question that came to mind when I photographed these clouds, says Tom Yulsman @ ImaGeo.

But the beautiful phenomenon I witnessed eventually led me to it.
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Mars is certainly cold. With temperatures that can plunge to more than negative 100 degrees Celsius, it’s bloody frigid!

But as cold as it might get, does it snow on Mars?

New Horizons opts for primary flyby path around Ultima Thule

The orbit of 2014 MU69 with the path of New Horizons [credit: NASA@Wikipedia]

“Ultima Thule” (2014 MU69) means “beyond the borders of the known world.” It takes nearly 300 years to orbit the Sun. Scientists ‘have no idea what to expect’.

After several weeks of sensitive searches for rings, small moons and other potential hazards around 2014 MU69, a Kuiper belt object nicknamed Ultima Thule, the dozen-member New Horizons hazard watch team gave the ‘all clear’ for the spacecraft to remain on a path that takes it about 2,200 miles (3,500 km) from Ultima Thule, instead of a hazard-avoiding detour that would have pushed it three times farther out, reports Sci-News.

“New Horizons is now targeted for the optimal flyby, over three times closer than we flew to Pluto. Ultima, here we come,” said New Horizons principal investigator Dr. Alan Stern, a researcher at Southwest Research Institute.

New Horizons will make its historic close approach to Ultima Thule at 12:33 a.m. EST on January 1, 2019.

See a passing comet this Sunday

Comet 46P/Wirtanen [image credit: NASA]

The comet can be found near the Pleiades star cluster, conditions permitting.

On Sunday, Dec. 16, the comet known as 46P/Wirtanen will make one of the 10 closest comet flybys of Earth in 70 years, and you may even be able to see it without a telescope, says Phys.org.

Although the approach will be a distant 7.1 million miles (11.4 million kilometers, or 30 lunar distances) from Earth, it’s still a fairly rare opportunity.

“This will be the closest comet Wirtanen has come to Earth for centuries and the closest it will come to Earth for centuries,” said Paul Chodas, manager of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in Pasadena, California.

Hyperactive Comet Approaches Earth

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It has been billed as The Comet of The Year.

Spaceweather.com

Nov. 26, 2018: Small but hyperactive Comet 46P/Wirtanen is approaching Earth and could soon become visible to the naked eye. On Dec. 16th, the kilometer-wide ball of dirty ice will be less than 11.5 million km away–making it one of the 10 closest-approaching comets of the Space Age. It already looks magnificent through amateur telescopes. On Nov. 26th, Gerald Rhemann took this picture using a 12-inch reflector in Farm Tivoli, Namibia:

“The comet is currently gliding through the southern constellation Fornax,” says Rhemann. “If you look carefully at the image, you can see galaxy NGC 922 near the comet’s head, and another galaxy ESO 479-2 on the left.”

Rhemann says that the comet’s emerald green atmosphere is 50 arcminutes wide. In other words–almost twice as wide as a full Moon. Its apparent diameter could double in the weeks ahead as the comet comes even closer. Because Wirtanen’s brightness is spread…

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