Science & TechnologyS


Sun

Rethinking the sun's cycles: New physical model reinforces planetary hypothesis

Simon Schmitt, Helmholtz Association of German Research Centres
Phys.org
Mon, 27 May 2024 00:00 UTC
the Sun
© UnknownThe Sun is currently approaching a maximum activity in the 11-year "Schwabe Cycle"
Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Latvia have posited the first comprehensive physical explanation for the sun's various activity cycles. It identifies vortex-shaped currents on the sun, known as Rossby waves, as mediators between the tidal influences of Venus, Earth as well as Jupiter and the sun's magnetic activity.

The researchers therefore present a consistent model for solar cycles of different lengths — and another strong argument to support the previously controversial planetary hypothesis. The results have now been published in the journal Solar Physics.

Although the sun, being near to us, is the best researched star, many questions about its physics have not yet been completely answered. These include the rhythmic fluctuations in solar activity. The most famous of these is that, on average, the sun reaches a radiation maximum every eleven years — which experts refer to as the Schwabe cycle.

This cycle of activity occurs because the sun's magnetic field changes during this period and eventually reverses polarity. This, in itself, is not unusual for a star — if it weren't for the fact that the Schwabe cycle is remarkably stable.

The Schwabe cycle is overlaid by other, less obvious fluctuations in activity ranging from a few hundred days to several hundred years, each named after their discoverers. Although there have already been various attempts to explain these cycles and mathematical calculations, there is still no comprehensive physical model.
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Gem

Groundbreaking new process lets scientists grow diamonds from scratch in 15 minutes

Deepa Jain
Live Science
Fri, 24 May 2024 20:33 UTC
synthetic diamond new process
© Bloomberg Creative/Getty ImagesA new technique has allowed scientists to create lab-grown diamonds at ambient temperatures and pressures in just 15 minutes.
Scientists have used a new technique to synthesize diamonds at normal, atmospheric pressure and without a starter gem, which could make the precious gemstones much easier to grow in the lab.

Natural diamonds form in Earth's mantle, the molten zone buried hundreds of miles beneath the planet's surface. The process takes place under tremendous pressures of several gigapascals and scorching temperatures exceeding 2,700 degrees Fahrenheit (1,500 degrees Celsius).

Similar conditions are employed in the method currently used to synthesize 99% of all artificially created diamonds. Called high-pressure and high-temperature (HPHT) growth, this method uses these extreme settings to coax carbon dissolved in liquid metals, like iron, to convert it to diamond around a small seed, or starter diamond.

However, the high pressures and temperatures are difficult to produce and maintain. Plus, the components involved affect the diamonds' size, with the largest being about a cubic centimeter, or about as big as a blueberry. Besides, HPHT takes a fairly long time — a week or two — to produce even these tiny gems. Another method, called chemical vapor deposition, eliminates some requirements of HPHT, like high pressures. But others persist, like the need for seeds.
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Info

Cosmic rays illuminate the past


University of Bern
Tue, 21 May 2024 17:24 UTC
site of Dispilio
© Dispilio Excavation ArchiveThe pile field at the site of Dispilio. Almost 800 piles, mostly made of juniper and oak wood, were sampled and dendrochronologically measured. This data forms the basis for the high-precision dating of this site. Dispilio is the first archaeological site to be dated to a precise year using the Miyake event of 5259 BC.
Researchers at the University of Bern have for the first time been able to pin down a prehistoric settlement of early farmers in northern Greece dating back more than 7,000 years to the year. For this they combined annual growth ring measurements on wooden building elements with the sudden spike of cosmogenic radiocarbon in 5259 BC. This provides a reliable chronological reference point for many other archaeological sites in Southeast Europe.

Dating finds plays a key role in archaeology. It is always essential to find out how old a tomb, settlement or single object is. Determining the age of finds from prehistoric times has only been possible for a few decades. Two methods are used for this: dendrochronology, which enables dating on the basis of sequences of annual rings in trees, and radiocarbon dating, which can calculate the approximate age of the finds by the decay rate of the radioactive carbon isotope 14C contained in the tree rings.

A team led by the Institute of Archaeological Sciences at the University of Bern has now succeeded in precisely dating timber from the archaeological site of Dispilio in northern Greece, where dating to the year had previously not been possible, to different building activities between 5328 and 5140 BC. The researchers made use of high-energy particles from space, which can be reliably dated to 5259 BC. Their research has been published in the journal Nature Communications.
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Info

Lost photos suggest Mars' mysterious moon Phobos may be a trapped comet in disguise

Abha Jain
Live Science
Wed, 22 May 2024 21:00 UTC
Previously unpublished photos of Mars' moon Phobos hint that the mysterious satellite may actually be a trapped comet — or perhaps just a piece of one, along with its twin moon Deimos.
Phobos and Deimos
© NASA/JPL-Caltech/GSFC/Univ. of ArizonaA composite photo of Mars with its twin moons Phobos and Deimos. New research suggests the pair may in fact be two halves of an ancient comet captured by Mars long ago.
Mars' moon Phobos may actually be a comet — or at least part of one — that was gravitationally captured by the Red Planet long ago, a new preprint study based on previously unpublished photos suggests.

For years, researchers have puzzled over the origins of Phobos and its twin, Deimos. Some have theorized that the moons are former asteroids lured in by Mars' gravity, because their chemical composition is similar to that of certain rocks in the main asteroid belt between Mars and Jupiter. However, computer models simulating this capture process have not been able to replicate the pair's near-circular paths around Mars.

Another hypothesis suggests that a giant impact, like that which created our moon, gouged the duo out of the Red Planet; but Phobos has a different chemical composition from Mars, making this scenario unlikely, too.

Figuring out exactly how Phobos was born is one of the aims of the Japan Aerospace Exploration Agency's Martian Moons eXploration (MMX) mission, slated to launch in 2026. Sonia Fornasier, an astronomy professor at the Paris Cité University and lead author of the new study, is an instrument scientist for the MMX mission. While she and other scientists were analyzing images to fine-tune the spacecraft's planned path, Fornasier stumbled upon unpublished photos.
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Blue Planet

Neanderthals and modern humans interbred 47,000 years ago, new analysis reveals

Michael Price
Science
Tue, 21 May 2024 19:48 UTC
neanderthal
© Fotokon/ShutterstockGenome analysis genomes refines timing of critical and mysterious juncture in human history.

Some 45,000 years ago, Bulgaria's Bacho Kiro caves hosted modern humans — depicted here in sculpture — whose genomes suggest they had recent Neanderthal ancestry.
Most people alive today carry traces of genes inherited from Neanderthals — the enduring legacy of prehistoric hookups with our extinct cousins. But researchers have long debated when and where that mingling happened, and whether these were one-off romps or commonplace trysts. Now, an analysis of ancient and modern genomes suggests contemporary people's Neanderthal DNA came from a single, prolonged period of mixing some 47,000 years ago.

The findings — released last week as a bioRxiv preprint that has yet to undergo peer review — sharpen the timeline for this critical and mysterious juncture in human history. It's the first paper to use dozens of ancient Homo sapiens genomes to address this question, and it may have implications for the timing of other major events in human evolution, such as the peopling of Australia.

Comment: As noted above, the era seems to be marked by other significant events:

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Bug

Fossil discovery: 308-million-year-old spider ancestor with prickly legs

Shubhangi Dua
Interesting Engineering
Fri, 17 May 2024 17:42 UTC
Douglassarachne acanthopoda fossil spider prickly legs
© Paul Selden/EurekaAlertFossilized Douglassarachne acanthopoda might have resemblance to modern harvestmen spiders.
Once a spider-like species that crawled through the Carboniferous coal forests of North America and Europe have now been traced back to an ancient species of arachnid named Douglassarachne acanthopoda.

A team of researchers from the University of Kansas, the Natural Museum of London, and the Museum für Naturkunde Berlin analyzed a fossil discovered by Bob Masek in the 1980s. It was later acquired by the David and Sandra Douglass Collection.

This fossil was examined recently to understand more about the diversity and evolutionary history of arachnids during the Carboniferous period.
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Mars

Global auroras on Mars

Dr. Tony Phillips
Space Weather Archive
Thu, 16 May 2024 21:55 UTC
Mars purple
© NASAAurora reaches deep into the Martian atmosphere
Feb 28, 2024: Earth isn't the only planet with auroras. Mars has them, too-on a global scale.

"Mars is experiencing its greatest level of auroral activity in the past 10 years," says Nick Schneider of the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP). "In February alone, there were three episodes of global auroras-an 'aurora hat trick' we've never seen before."

Orbiting high above Mars, NASA's MAVEN spacecraft recorded the auroras on 3-4 Feb, 7-10 Feb and 15-16 Feb. This animation shows the last two of these episodes in a looping time series:

Global Auroras on Mars from Earth to Sky Calculus on Vimeo.
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Cassiopaea

Best of the Web: Unprecedented South Pacific auroras confirm recent geomagnetic storm as 'Great Storm', in same class as 1859 Carrington Event


Spaceweather.com
Thu, 16 May 2024 20:59 UTC

Comment: Oh yeah folks, we're in the middle of it now!


On the south Pacific island of New Caledonia, no one expects to see auroras. Ever. Situated about halfway between Tonga and Australia, the cigar-shaped island is too close to the equator for Northern or Southern Lights. Yet on May 10, 2024, this happened:
aurora new caledonia
© Frédéric DesmoulinsThe auroras australis have been observed as far away as New Caledonia (Boulouparis). Photo taken on the evening of May 11, 2024 at 8:00 p.m. Nikon D500, 16-80 f/2.8-4.0, ISO 5000, 20s f/3.2. Historic first for New Caledonia.
"I have rarely been so happy when taking a photo!" says Frédéric Desmoulins, who photographed the display from Boulouparis in the island's south province. "I could see the red color of the auroras with my naked eye. According to the New Caledonian Astronomy Society, these photos are the first for this territory."

"The auroral visibility from New Caledonia is really unique and extremely valuable," says Hisashi Hayakawa, a space weather researcher at Japan's Nagoya University. "The last time sky watchers saw auroras in the area may have been during the Carrington Event of Sept. 1859, when auroras were sighted from a ship in the Coral Sea."

Comment: Now get this: in December 1859 the Atlantic magazine published a detailed report about the 1859 Carrington Event, and noted, among many other things in its superb report (oh for the days when The Atlantic published good research), that:
The aurora borealis of August 28th was surpassingly brilliant not only in the northern portion of this continent, but also as far south as the equator, — as well as in Cuba, Jamaica, California, and the greater portion of Europe. [...]

In Jamaica the aurora borealis was witnessed for the first time, perhaps, since the discovery of this island by Columbus. So rare is the phenomenon in those latitudes, that it was taken for the glare of a fire, and was associated with the recent riots.
Guess what erupted in New Caledonia three days after auroras were sighted there... serious rioting akin to a 'civil war':

France deploys military to quell independence protests and serious rioting in Pacific territory of New Caledonia

Spaceweather.com also reports that another massive 'Carrington-class' sunspot is poised to hurl a geomagnetic storm Mars' way...
MONSTER SUNSPOT TARGETS MARS: First Earth, now Mars. Carrington-class sunspot AR3664 is now directly facing the Red Planet. NASA's Mars rover Perseverance saw it yesterday through the dusty air of Jezero Crater:

mars sunspot rover AR3664
© NASA's Mars rover Perseverance
On May 14th, AR3664 produced an X8.6-class solar flare, the strongest flare of the solar cycle, and hurled a corresponding CME directly toward Mars. NASA models suggest it should hit Mars on May 17th, potentially sparking global auroras.

"We're bracing for impact!" says says Nick Schneider of the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP). Schneider works with an ultraviolet camera on NASA's MAVEN spacecraft, which may be able to observe the display. Stay tuned!


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Galaxy

Scientists discover huge magnetic toroids in the Milky Way halo

Chen Na
PhysOrg
Mon, 13 May 2024 20:42 UTC
magnetic fields toroids milky way
© NAOCMagnetic fields in the halo of the Milky Way have a toroidal structure, extending in the radius range of 6,000 light-years to 50,000 light-years from the galaxy center. The sun is at about 30,000 light-years.
The origin and evolution of cosmic magnetic fields is a long-standing unsolved question at the frontier of astronomy and astrophysics research and has been selected as one of the key areas of investigation for many major world-class radio telescopes, including the Square Kilometer Array (SKA) under construction. To determine the large-scale magnetic field structures in the Milky Way has been a major challenge for many astronomers in the world for decades.

In a new study published in The Astrophysical Journal on May 10, Dr. Xu Jun and Prof. Han Jinlin from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) have revealed huge magnetic toroids in the halo of the Milky Way, which are fundamental for cosmic ray propagation and provide crucially constraint on the physical processes in the interstellar medium and the origin of cosmic magnetic fields.
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Clipboard

Writing by hand beats typing for thinking and learning

Jonathan Lambert
NPR
Sat, 11 May 2024 20:08 UTC
handwriting
© www.behance.net
If you're like many digitally savvy Americans, it has likely been a while since you've spent much time writing by hand.

The laborious process of tracing out our thoughts, letter by letter, on the page is becoming a relic of the past in our screen-dominated world, where text messages and thumb-typed grocery lists have replaced handwritten letters and sticky notes. Electronic keyboards offer obvious efficiency benefits that have undoubtedly boosted our productivity — imagine having to write all your emails longhand.

To keep up, many schools are introducing computers as early as preschool, meaning some kids may learn the basics of typing before writing by hand.

But giving up this slower, more tactile way of expressing ourselves may come at a significant cost, according to a growing body of research that's uncovering the surprising cognitive benefits of taking pen to paper, or even stylus to iPad — for both children and adults.

Comment:

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