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Researchers have come up with a way to turn silicon into a direct bandgap semiconductor, opening the door to the manufacture of ultrathin silicon solar cells.

Researchers have come up with a way to turn silicon into a direct bandgap semiconductor, opening the door to the manufacture of ultrathin silicon solar cells.

A team of researchers has developed a printing technique capable of forming a periodic nano/microstructure on the surface of a polydimethylsiloxane (PDMS) slab and easily transferring it onto the surface of a glass substrate. This technique enables us to create materials with useful functions -- including water-repellency and the ability to generate structural colors -- without expensive equipment and complex processes. In addition, the technique may be used to fabricate materials capable of realizing anti-fogging and/or generating structural colors on their surfaces -- functions potentially useful in the development of innovative gas sensors.

Fewer lakes are freezing over each winter compared with past years, posing environmental and economic consequences around the world

https://traffic.libsyn.com/secure/sciencesalon/mss482_Michael_Shermer_2024_10_31.mp3 Download MP3

In this solo episode, Michael Shermer discusses the upcoming election, reflecting on the historical context of past elections and the political polarization that has intensified over the years.

Researchers have developed a computational technique that makes spatial RNA transcripts more accessible and precise, allowing them to be visualized at microscopic resolution.

Researchers have developed a computational technique that makes spatial RNA transcripts more accessible and precise, allowing them to be visualized at microscopic resolution.

Researchers have developed a compact, wearable ultrasound device that monitors muscle activity. Attachable to the skin with an adhesive and powered by a small battery, the device wirelessly captures high-resolution images of muscle movements, enabling continuous, long-term monitoring. When worn on the rib cage, it effectively monitored diaphragm function for respiratory health assessments. When worn on the forearm, it accurately captured hand gestures, allowing users to control a robotic arm and even navigate virtual games. This new technology has potential applications in healthcare for conditions affecting muscle function, as well as in human-machine interfaces for more natural robotic control.

Researchers have developed a compact, wearable ultrasound device that monitors muscle activity. Attachable to the skin with an adhesive and powered by a small battery, the device wirelessly captures high-resolution images of muscle movements, enabling continuous, long-term monitoring. When worn on the rib cage, it effectively monitored diaphragm function for respiratory health assessments. When worn on the forearm, it accurately captured hand gestures, allowing users to control a robotic arm and even navigate virtual games. This new technology has potential applications in healthcare for conditions affecting muscle function, as well as in human-machine interfaces for more natural robotic control.

Imagine a sweater that powers electronics to monitor your health or charge your mobile phone while running. This development faces challenges because of the lack of materials that both conduct electricity stably and are well suited for textiles. Now a research group presents an ordinary silk thread, coated with a conductive plastic material, that shows promising properties for turning textiles into electricity generators.

Takeout containers get your favorite noodles from the restaurant to your dining table (or couch) without incident, but they are nearly impossible to recycle if they are made from foil-lined plastics. Research suggests that replacing the plastic layer with paper could create a more sustainable packaging material. The researchers used mechanical demonstrations and computer simulations to identify paper-aluminum laminate designs that won't compromise on performance.

The next step for fully integrated textile-based electronics to make their way from the lab to the wardrobe is figuring out how to power the garment gizmos without unfashionably toting around a solid battery. Researchers have taken a new approach to the challenge by building a full textile energy grid that can be wirelessly charged. In their recent study, the team reported that it can power textile devices, including a warming element and environmental sensors that transmit data in real-time.

Researchers have developed a revolutionary injectable granular filler that could transform the way diabetic wounds are treated, potentially improving patient outcomes. The groundbreaking study introduced an innovative approach about using specialized porous dermal fillers that accelerate tissue healing and regeneration.

A research team developed a new paradigm for the control of quantum emitters, providing a new method for modulating and encoding quantum photonic information on a single photon light stream.

A research team developed a new paradigm for the control of quantum emitters, providing a new method for modulating and encoding quantum photonic information on a single photon light stream.

Comets have long been seen as omens and portents, and it’s easy to understand why. They first appear as faint smudges of light in the sky, sometimes fading soon after and sometimes becoming brighter than the planets, with a long, glowing tail. They have been observed throughout human history, but it wasn’t until the eighteenth century that astronomers began to predict the return of some comets. Even today, we can’t predict the return of most comets until after they swing through the inner solar system. If such a comet happens to be heading toward Earth, we wouldn’t know about it until too late. But that could change thanks to our observations of meteor showers.

Comets originate from the Oort cloud, the icy remnant of our solar system’s birth that surrounds the Sun as a sphere 100,000 AU in diameter. Whether through a close collision with another Oort object or the nearby passing of a star, some of these distant chunks of ice and rock are sent tumbling toward the inner solar system. They can come from any direction in the sky, and once they dance near the Sun they may not return for hundreds or thousands of years. Any comet with a period longer than 200 years is known as a long-period comet, and these are the hardest to predict.

Most long-period comets pose no threat to Earth. They might appear bright in the evening or morning sky, but their orbits don’t cross Earth’s orbit, so there is no risk of impact. But some long-period comets could pose an impact threat to Earth. We know this in part because we’ve been hit by comets before, and in part because we observe regular meteor showers. Showers such as the Geminids, Perseids, and Orionids are caused by the dusty trails left by comets as they cross Earth’s orbit. In these cases, we have even identified the originating comets as Phaeton, Swift-Tuttle, and Halley’s. But of these, only Swift-Tuttle is a long-period comet (barely) with an orbital period of 257 years.

Illustration of long-period comets and the Oort cloud. Credit: National Astronomical Observatory of Japan

These connections between comets and meteor showers were made by first knowing the comet’s orbit then connecting its path to known showers. In principle, we should be able to do it the other way around. Identify what the path of a meteor shower is, and then use that to search for its long-period comet. As new telescopes such as Rubin Observatory come online, this approach could become a useful tool in the search for impact threats. A recent study on the arXiv shows how this would work.

The team ran simulations of long-period comets ranging from 200 to 4,000 years. They estimated the dust trails these hypothetical comets would produce, then set out to determine if astronomers could use these trails to work backwards to locate the originating comet while it is far from the Sun. In anticipation of having high-resolution sky surveys, the team assumed astronomers could observe them at the anticipated resolution of Rubin Observatory. They found that the orbits of many comets don’t produce showers useful for prediction, but in 17 cases, the showers could be used to identify comets months or years before they would typically be noticed.

The expected orbit for the Aurigid shower. Credit: Hemmelgarn, et al

To prove this point even further, the team also looked at a meteor shower called the ?-Hydrids, a faint shower that appears in early December. The origin of the sigma-Hydrids was not known until the appearance of Comet Nishimura in 2023. Once the orbit was determined, astronomers found a possible connection to the sigma-Hydrid showers. Using known observations of the shower before 2023, the team was able to determine a possible orbit for the comet. They found that with a Rubin-like sky search, astronomers could have found Nishimura eight months before its actual discovery.

Reference: Hemmelgarn, Samantha, et al. “How Meteor Showers Can Guide the Search for Long Period Comets.” arXiv preprint arXiv:2410.02883 (2024).

The post Astronomers Predict the Orbits of Potentially Hazardous Comets From Meteor Showers appeared first on Universe Today.

Radiocarbon dating and DNA analysis have revealed that a complete skeleton found in a 2nd-century cemetery is made up of bones from many people spanning thousands of years – but we don’t know who assembled it or why

Radiocarbon dating and DNA analysis have revealed that a complete skeleton found in a 2nd-century cemetery is made up of bones from many people spanning thousands of years – but we don’t know who assembled it or why

Comet C/2023 A3 Tsuchinshan-ATLAS survived perihelion to become a fine dusk object for northern hemisphere observers.

It was an amazing month for astronomy. Not only were we treated to an amazing second solar storm for 2024 that sent aurorae as far south as the Caribbean, but we had a fine naked eye comet: C/2023 A3 Tsuchinshan-ATLAS.

The comet on October 24th, along with the Milky Way over the Sea of Japan as seen from Yuzhno-Morskoy (Nakhodka) Russia. Credit: Filipp Romanov.

Discovered in early 2023, this one actually performed as expected, and topped out as the best comet for 2024. Southern hemisphere observers got a portent of things to come in September, as the comet threaded the dawn skies.

The evolution of the comet post-perihelion through October 25-30th. Credit: Eliot Herman Peril at Perihelion

Then came the big wild card of perihelion. The comet passed just 58.6 million kilometers from the Sun on September 27th. At its maximum, the comet hit nearly -5th magnitude. The dust and plane crossing for the comet were both especially dramatic, as we saw a sharp spiky anti-tail trace out the comet’s orbital trail and appear to pierce the Sun as seen in views from SOHO’s LASCO C2 and C3 imagers.

But would the comet remain bright for its evening encore? This time, luck was on our side, as the comet held at +1st magnitude for about a week, and joined Venus in the dusk sky. As it began its rapid ascent, Comet ‘T-ATLAS’ unfurled its tail about a dozen degrees in length, all while keeping its remarkable anti-tail pointing sunward.

The comet from October 18th, still exhibiting a spiky ‘anti-tail. Credit: Efrain Morales. A ‘Just Point-and-Shoot’ Comet

And then the pictures came pouring in. Comet T-ATLAS was at its photogenic best in early October, as it became an easy target against the starry backdrop. Usually, +2nd magnitude or brighter is the cutoff for catching a comet along with foreground objects. This time, you could actually simply set your smartphone camera to night mode, and capture a decent handheld shot of the comet.

The comet from October 19th, as seen from Ottawa, Canada. Credit: Andrew Symes

Plus, light pollution didn’t seem to faze this comet. We saw shots of the comet from downtown Los Angeles and other urban areas, as folks were treated to the best comet in recent memory since the dawn apparition of F3 NEOWISE in 2020.

Venus, a meteor, an airplane trail, and Comet T-ATLAS from Malaysia. Credit: Shahrin Ahmad.

And to think: the last time a really brilliant comet swung by (C/1995 O1 Hale-Bopp a generation ago in 1997) digital imaging was in its infancy, and film still dominated the market… just think what we might manage to do with such a comet today?

“I drove north for more than three hours, and reached the seashore facing the Sea of Japan after sunset,” says astrophotographer Hisayoshi Kato on Flickr, “It was fortunate that the sky was clear at the site, and I could enjoy the comet sinking into the Sea of Japan (over) the weekend.”

Comet C/2023 A3 Tsuchinshan-ATLAS from October 26th. Credit: Hisayoshi Kato. Awaiting Next ‘Great Comet’

To be sure, it’s only a matter of time before the next ‘Comet of the Century’ makes itself known. Right now, Comet T-ATLAS is still a decent +6th magnitude binocular object in Ophiuchus, outbound on its nearly quarter-of-a-million-year orbit. Alas, a second sungrazer encore for October never came to pass, as Comet C/2024 S1 ATLAS ended its cometary career at perihelion earlier this week…

An amazing parting shot of the comet from October 29th. Credit: Gianluca Masi.

“These days, we all had an extraordinary proof of the splendor of the night sky,” astronomer Gianluca Masi noted in a recent Facebook post. “Comet C/2023 A3 Tsuchinshan-ATLAS is still putting on a show… but the firmament is always a prodigy of emotions and wonders, as those who regularly turn their gaze to the stars know.”

Comet T-ATLAS from downtown Bristol, Tennessee. Credit: Dave Dickinson.

When’s the next one? Well, we do have the promise of a similar comet coming right up in January 2025. C/2024 G3 ATLAS may reach -1st magnitude or brighter near perihelion.

Thanks to everyone that got out there and sent images to the Universe Today Flickr pool. Here’s to the next yet-to-be named bright comet, waiting in the wings to take center stage in the drama of the inner solar system and the skies of Earth.

The post Amazing Reader Views of Comet A3 Tsuchinshan-ATLAS From Around the World appeared first on Universe Today.

An off-the-shelf millimetre wave sensor can pick out the tiny vibrations made by a smartphone's speaker, enabling an AI model to transcribe the conversation, even at a distance in a noisy room