Science & TechnologyS


Saturn

Saturn's seasonal spectacle: Hubble's ultra-sharp vision unveils ring spoke phenomenon


Sci Tech Daily
Mon, 25 Dec 2023 07:58 UTC
photo of Saturn was taken by NASA’s Hubble Space Telescope on October 22, 2023
© NASA, ESA, STScI, Amy Simon (NASA-GSFC)This photo of Saturn was taken by NASA’s Hubble Space Telescope on October 22, 2023, when the ringed planet was approximately 850 million miles from Earth. Hubble’s ultra-sharp vision reveals a phenomenon called ring spokes.
Saturn’s spokes are transient features that rotate along with the rings. Their ghostly appearance only persists for two or three rotations around Saturn. During active periods, freshly-formed spokes continuously add to the pattern.
Levitated Dust Takes a Carousel Ride Around the Giant Ringworld

Though Saturn's unusual-looking "cup handle" features were first noted by Galileo in 1610, it would be another 45 years before they were described by Christiaan Huygens as a disk surrounding Saturn. Subsequently, ground-based telescopes could only distinguish four unique concentric rings, labeled A, B, C, and D. Not until the 1980s did NASA's two Voyager probes fly by Saturn to photograph thousands of concentric ringlets. An even bigger surprise to Voyager scientists were dark, radial spoke-like patterns in the ring plane that came and went as they revolved around Saturn.

Over the past three decades, the Hubble Space Telescope has picked up where the Voyagers have left off. Hubble's ultra-sharp vision is the next best thing to being there. Hubble follows the ring spoke "merry-go-round" every year. It's believed the dark spokes are dust particles electrostatically levitated above the ring plane. They seem to change in abundance with Saturn's seven-year-long seasons. And, this may be linked to changes in Saturn's magnetic field, as it is battered by the solar wind.

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Telescope

After 2 years in space, the James Webb telescope has broken cosmology. Can it be fixed?

Ben Turner
Live Science
Sat, 23 Dec 2023 00:00 UTC
illustration
© AlamyAn artist's illustration of the James Webb Space Telescope.
For decades, measurements of the universe's expansion have suggested a disparity known as the Hubble tension, which threatens to break cosmology as we know it. Now, on the eve of its second anniversary, a new finding by the James Webb Space Telescope has only entrenched the mystery.

Something is awry in our expanding cosmos.

Nearly a century ago, the astronomer Edwin Hubble discovered the balloon-like inflation of the universe and the accelerating rush of all galaxies away from each other. Following that expansion backward in time led to our current best understanding of how everything began — the Big Bang.

But over the past decade, an alarming hole has been growing in this picture: Depending on where astronomers look, the rate of the universe's expansion (a value called the Hubble constant) varies significantly.

Now, on the second anniversary of its launch, the James Webb Space Telescope (JWST) has cemented the discrepancy with stunningly precise new observations that threaten to upend the standard model of cosmology.

The new physics needed to modify or even replace the 40-year-old theory is now a topic of fierce debate.
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Brain

Power of illusion can help with learning new movements

Tokyo Metropolitan University
Medical Xpress
Wed, 27 Dec 2023 00:00 UTC
visual-motor illusion
© Scientific Reports (2023). DOI: 10.1038/s41598-023-47435-8(a) The Visual-motor illusion group observed a video of their counterclockwise ball rotation task. (b) The action observation group watched the same video as the visual-motor illusion group.
Researchers from Tokyo Metropolitan University showed that visual aids that create the illusion of movement, like a screen placed in front of one's hand showing the hand move, can improve motor performance and the early stages of motor learning. Compared to observing third-person motions, functional near-infrared spectroscopy data also showed greater changes in brain activity in regions associated with motor learning.

Findings like this might inform new treatment strategies for hemiplegic stroke patients. The study is published in the journal Scientific Reports.

Visual-motor illusion (VMI) is the curious illusion of watching your body move even while it is still. Imagine having a tablet screen placed in front of your hand. Your hand is hidden behind the tablet, and your hand is not moving. Now, imagine the screen playing a video of your hand moving; your eyes are telling you that your hand is moving, but it is not moving at all.
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Archaeology

Perfectly preserved dinosaur embryo found inside fossilized egg

Ben Taub
IFL Science
Tue, 26 Dec 2023 19:18 UTC
oviraptorosaur
© Xing et al., 2021The oviraptorosaur embryo known as Baby Yingliang.
The 66- to 72-million-year-old specimen is one of the most complete dinosaur embryos ever found.

An incredibly rare, fully articulated dinosaur embryo has been found inside a fossilized egg that had been collecting dust for over a decade in the storage room of a museum in China. Thought to be between 66 and 72 million years old, the unborn specimen reveals an incredible link between dinosaurs and modern birds.

Belonging to a group of feathered, toothless theropods known as oviraptorosaurs, the unhatched creature is estimated to be about 27 centimeters (10.6 inches) long, and marks the first discovery of a dinosaur embryo displaying a posture that is typical of present-day bird embryos. Shortly before hatching, modern birds engage in a series of maneuvers known as tucking, which involves curving the body and bringing the head down under the wing, yet the evolutionary origins of this behavior have until now remained unknown.
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Moon

Korean lunar orbiter reveals Moon's far side is inexplicably more conductive

Stephen Luntz
IFL Science
Mon, 18 Dec 2023 01:42 UTC
moon far side dark side
© NASA via wikimedia commonsWe've known for almost 60 years that the far side of the Moon has almost no seas, but it's only know we have learned it is more conductive than the near
It's just one of the intriguing things the Danuri orbiter has revealed that previous missions missed.

There's something odd about the far side of the Moon, scientists have concluded based on data from the Korean Pathfinder Lunor Orbiter. The results are yet to be published, but suggest a discrepancy between the conductivity of the near and far sides, which so far lacks a plausible explanation.

Lunar exploration is becoming a global affair. Along with missions from the United States, China, India and Japan, the Korean Aerospace Research Institute has had an orbiter around our satellite for a year. Nicknamed Danuri, the mission is proving there is plenty the larger nations have missed.

Although the Institute is coy on the results over that time, Nature has been given advance notice of some of what has been found.
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HAL9000

The world's first human brain-scale supercomputer will go live next year

Ellie Zolfagharifard
Business Insider
Fri, 15 Dec 2023 00:00 UTC
deep south
Our brains are remarkably energy efficient.

Using just 20 watts of power, the human brain is capable of processing the equivalent of an exaflop — or a billion-billion mathematical operations per second.

Now, researchers in Australia are building what will be the world's first supercomputer that can simulate networks at this scale.

The supercomputer, known as DeepSouth, is being developed by Western Sydney University.

When it goes online next year, it will be capable of 228 trillion synaptic operations per second, which rivals the estimated rate of operations in the human brain.

The hope is to better understand how brains can use such little power to process huge amounts of information.

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Airplane Paper

Physicist discovers 'paradox-free' time travel is theoretically possible

David Nield
Science Alert
Sun, 17 Dec 2023 00:00 UTC
hole
© andrey_I/ShutterstockTime Travel Web
No one has yet managed to travel through time - at least to our knowledge - but the question of whether or not such a feat would be theoretically possible continues to fascinate scientists.

As movies such as The Terminator, Donnie Darko, Back to the Future and many others show, moving around in time creates a lot of problems for the fundamental rules of the Universe: if you go back in time and stop your parents from meeting, for instance, how can you possibly exist in order to go back in time in the first place?

It's a monumental head-scratcher known as the 'grandfather paradox', but a few years ago physics student Germain Tobar, from the University of Queensland in Australia, worked out how to "square the numbers" to make time travel viable without the paradoxes.

Tobar explained back in 2020:
"Classical dynamics says if you know the state of a system at a particular time, this can tell us the entire history of the system. However, Einstein's theory of general relativity predicts the existence of time loops or time travel - where an event can be both in the past and future of itself - theoretically turning the study of dynamics on its head."
What the calculations show is that space-time can potentially adapt itself to avoid paradoxes.
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Magnify

Reindeer's blue eyes act as night vision goggles to help them find food in winter

Nadeem Badshah
The Guardian
Thu, 21 Dec 2023 15:32 UTC
reindeer eye color change
© Alexandre BuisseReindeer eyes change color with the seasons
Animals' eyes change colour as colder months approach to enhance UV sight, helping them spot lichen vital for their survival

Rudolph does not need to use his famous red nose to guide his fellow reindeer as the animals have a special form of night vision that they use to forage for food, scientists have concluded.

Researchers looked into why the species are the only mammals whose eyes change colour depending on the season, from golden-orange in summer to a blue hue in the winter months.

The study found that while the colour shift may help them see better in the peak of winter when snowfall is heavy, it also allows their eyes to transmit ultraviolet light.
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Telescope

JWST spots new rings, moons around Uranus


WEBB Space Telescope
Mon, 18 Dec 2023 19:59 UTC
uranus rings moons
© JWST/NASARings and moons of Uranus captured by the James Web Space Telescope
NASA's James Webb Space Telescope recently trained its sights on unusual and enigmatic Uranus, an ice giant that spins on its side. Webb captured this dynamic world with rings, moons, storms, and other atmospheric features - including a seasonal polar cap. The image expands upon a two-color version released earlier this year, adding additional wavelength coverage for a more detailed look.

With its exquisite sensitivity, Webb captured Uranus' dim inner and outer rings, including the elusive Zeta ring - the extremely faint and diffuse ring closest to the planet. It also imaged many of the planet's 27 known moons, even seeing some small moons within the rings.

In visible wavelengths as seen by Voyager 2 in the 1980s, Uranus appeared as a placid, solid blue ball. In infrared wavelengths, Webb is revealing a strange and dynamic ice world filled with exciting atmospheric features.

One of the most striking of these is the planet's seasonal north polar cloud cap. Compared to the Webb image from earlier this year, some details of the cap are easier to see in these newer images. These include the bright, white, inner cap and the dark lane in the bottom of the polar cap, toward the lower latitudes.
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Galaxy

Astronomers detect almost 100 new extremely metal-poor galaxies

Tomasz Nowakowski
Phys.org
Fri, 15 Dec 2023 00:00 UTC
galaxies
© unknownTwo most metal-poor galaxies identified in this work. The left, middle and right.
By analyzing the early data from the Dark Energy Spectroscopic Instrument (DESI), an international team of astronomers has identified 95 new extremely metal-poor galaxies at a low redshift. The finding is detailed in a paper published December 1 on the pre-print server arXiv.

Extremely metal-poor galaxies (XMPGs) are the ones with metallicity below 0.1 of the solar metallicity. Given that these galaxies are chemically unevolved, they can serve as excellent laboratories for investigating the chemical evolution theories of galaxies and studying the physical processes in the early stages of their evolution.

Although XMPGs are assumed to be quite common at high redshift, they are difficult to observe due to their low masses. Therefore, astronomers are interested in the observations of local XMPGs at low redshift, as they are perceived as possible analogs of primeval high-redshift young galaxies of this type in terms of mass and metallicity.

Now, a group of astronomers led by Hu Zou of the University of Chinese Academy of Sciences in Beijing, China, has obtained a large sample of XMPGs based on the early data from DESI.
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