Science & TechnologyS


Nebula

Intriguing ripples revealed in slow-motion bubble collapse

Thamarasee Jeewandara
Phys.org
Mon, 17 Aug 2020 12:00 UTC
bubble
© Science Advances, doi: 10.1126/science.aba0593 Oliver McRae/Boston University,Ripple effects forming on sheets of a bubble film photographed mid-collapse.
A recent feature cover photo on Science portrayed a bubble in mid-collapse, based on a study conducted by Alexandros T. Oratis et al. The research team in mechanical engineering, mathematics and aerospace engineering at Boston University, MIT and Princeton University demonstrated the formation of intriguing wave-like patterns when bubbles underwent collapse. Using a complex lighting setup and fast shutter speed in the lab, perfectly aligned to capture a fleeting moment, within one second, they photographed the tiny bubble emerging from the surrounding media of dense silicone oil.

The rupture and collapse of viscous bubbles are widespread in nature and in industrial applications. The phenomenon is accompanied by elastic sheets that develop radial wrinkles. While the weight of the film appeared to play a dominant role during film collapse and wrinkling instability, in this work, gravity appeared to play a surprisingly negligible role. Based on fluid mechanics of the phenomena, Oratis et al. showed surface tension to be the driving factor during collapse to initiate dynamic buckling instability and wrinkling behavior, accompanied with the breakdown of curved viscous and viscoelastic films. The research work is relevant to understand industrial and chemical applications, including aerosol production from exhalation events in the respiratory tract.

Comment: Bubbles are proving to be quite insightful when it comes to the workings of our world: Light flows like a river when shone through a soap bubble

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Moon

Moon is drifting away from Earth says NASA


NASA
Tue, 11 Aug 2020 06:18 UTC
Laser Reflector
© NASAA close-up photograph of the laser reflecting panel deployed by Apollo 14 astronauts on the Moon in 1971.
Dozens of times over the last decade NASA scientists have launched laser beams at a reflector the size of a paperback novel about 240,000 miles (385,000 kilometers) away from Earth. They announced today, in collaboration with their French colleagues, that they received signal back for the first time, an encouraging result that could enhance laser experiments used to study the physics of the universe.

The reflector NASA scientists aimed for is mounted on the Lunar Reconnaissance Orbiter (LRO), a spacecraft that has been studying the Moon from its orbit since 2009. One reason engineers placed the reflector on LRO was so it could serve as a pristine target to help test the reflecting power of panels left on the Moon's surface about 50 years ago. These older reflectors are returning a weak signal, which is making it harder to use them for science.

Scientists have been using reflectors on the Moon since the Apollo era to learn more about our nearest neighbor. It's a fairly straightforward experiment: Aim a beam of light at the reflector and clock the amount of time it takes for the light to come back. Decades of making this one measurement has led to major discoveries.

One of the biggest revelations is that the Earth and Moon are slowly drifting apart at the rate that fingernails grow, or 1.5 inches (3.8 centimeters) per year. This widening gap is the result of gravitational interactions between the two bodies.

"Now that we've been collecting data for 50 years, we can see trends that we wouldn't have been able to see otherwise," said Erwan Mazarico, a planetary scientist from NASA's Goddard Space Flight Center in Greenbelt, Maryland who coordinated the LRO experiment that was described on August 7 in the journal Earth, Planets and Space.

"Laser-ranging science is a long game," Mazarico said.

But if scientists are to continue using the surface panels far into the future, they need figure out why some of them are returning only a 10th of the expected signal.
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Solar Flares

Cosmic rays and the weakening solar cycle

Dr.Tony Phillips
Space Weather Archive
Tue, 11 Aug 2020 06:00 UTC
Sunspot cycles
The already weakening sunspot cycle took a sharp nose-dive during Solar Cycle 24. The red curve is one prediction for upcoming Solar Cycle 25.
Cosmic rays are bad-and they're going to get worse. That's the conclusion of a new study entitled "Galactic Cosmic Radiation in Interplanetary Space Through a Modern Secular Minimum" just published in the journal Space Weather.

"During the next solar cycle, we could see cosmic ray dose rates increase by as much as 75%," says lead author Fatemeh Rahmanifard of the University of New Hampshire's Space Science Center. "This will limit the amount of time astronauts can work safely in interplanetary space."

Cosmic rays are the bane of astronauts. They come from deep space, energetic particles hurled in all directions by supernova explosions and other violent events. No amount of spacecraft shielding can stop the most energetic cosmic rays, leaving astronauts exposed whenever they leave the Earth-Moon system.

Back in the 1990s, astronauts could travel through space for as much as 1000 days before they hit NASA safety limits on radiation exposure. Not anymore. According to the new research, cosmic rays could limit trips to as little as 290 days for 45-year old male astronauts, and 204 days for females. (Men and women have different limits because of unequal dangers to reproductive organs.)

Why are cosmic rays growing stronger? Blame the sun. The sun's magnetic field wraps the entire solar system in a protective bubble, normally shielding us from cosmic rays. In recent decades, however, that shield has been growing weaker-a result of the sputtering solar cycle.

Comment: See also:

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Cassiopaea

Supernova may have caused mass extinction on Earth

Lois Yoksoulian
Phys.org
Tue, 18 Aug 2020 21:37 UTC
supernova
© Jesse MillerA team of researchers led by professor Brian Fields hypothesizes that a supernova about 65 light-years away may have contributed to the ozone depletion and subsequent mass extinction of the late Devonian Period, 359 million years ago. Pictured is a simulation of a nearby supernova colliding with and compressing the solar wind. Earth's orbit, the blue dashed circle, and the Sun, red dot, are shown for scale.
Imagine reading by the light of an exploded star, brighter than a full moon — it might be fun to think about, but this scene is the prelude to a disaster when the radiation devastates life as we know it. Killer cosmic rays from nearby supernovae could be the culprit behind at least one mass extinction event, researchers said, and finding certain radioactive isotopes in Earth's rock record could confirm this scenario.

A new study led by University of Illinois, Urbana-Champaign astronomy and physics professor Brian Fields explores the possibility that astronomical events were responsible for an extinction event 359 million years ago, at the boundary between the Devonian and Carboniferous periods.

The paper is published in the Proceedings of the National Academy of Sciences.

Comment: See also: The Seven Destructive Earth Passes of Comet Venus

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Attention

Binary companion of our Sun postulated by Harvard


Center for Astrophysics/Harvard & Smithsonian
Tue, 18 Aug 2020 22:57 UTC
Nemesis
© M. WeissArtist's conception of a potential solar companion, which theorists believe was developed in the Sun's birth cluster and later lost. If proven, the solar companion theory would provide additional credence to theories that the Oort cloud formed as we see it today, and that Planet Nine was captured rather than formed in place.
Cambridge, MA - A new theory published today in The Astrophysical Journal Letters by scientists from Harvard University suggests that the Sun may once have had a binary companion of similar mass. If confirmed, the presence of an early stellar companion increases the likelihood that the Oort cloud was formed as observed and that Planet Nine was captured rather than formed within the solar system.

Dr. Avi Loeb, Frank B. Baird Jr. Professor of Science at Harvard, and Amir Siraj, a Harvard undergraduate student, have postulated that the existence of a long-lost stellar binary companion in the Sun's birth cluster — the collection of stars that formed together with the Sun from the same dense cloud of molecular gas — could explain the formation of the Oort cloud as we observe it today.

Popular theory associates the formation of the Oort cloud with debris left over from the formation of the solar system and its neighbors, where objects were scattered by the planets to great distances and some were exchanged amongst stars. But a binary model could be the missing piece in the puzzle, and according to Siraj, shouldn't come as a surprise to scientists. "Previous models have had difficulty producing the expected ratio between scattered disk objects and outer Oort cloud objects. The binary capture model offers significant improvement and refinement, which is seemingly obvious in retrospect: most Sun-like stars are born with binary companions."

If the Oort cloud was indeed captured with the help of an early stellar companion, the implications for our understanding of the solar system's formation would be significant. "Binary systems are far more efficient at capturing objects than are single stars," said Loeb. "If the Oort cloud formed as observed, it would imply that the Sun did in fact have a companion of similar mass that was lost before the Sun left its birth cluster."
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Arrow Down

Project CHARIOT launched by DARPA to protect Big Tech profits

Raul Diego
Mint Press News
Tue, 18 Aug 2020 22:43 UTC
DARPA Project Chariot
© Mint Press News
The U.S. Military-Industrial complex is sprinting on a chariot to shore up the encryption space before the next era of computation upends the entire digital edifice built on semiconductors and transistors. But, the core of the effort is protecting markets for Big Tech and all of its tentacles, which stand to lose years or even decades of profits should the new tech be rolled out too quickly.

DARPA's newest program seeks to create an encryption technology standard across the breadth and scope of the Internet of Things (IoT). The Cryptography for Hyper-scale Architectures in aa Robust Internet Of Things or Project CHARIOT "will prototype low-cost, low-footprint, post-quantum cryptographic techniques with minimal energy use for devices in an IoT" on the 5G network, according to the Pentagon's boutique agency's SBO.

Consumer-side IoT, like smart home devices, had seen considerable growth in 2019 and expectations were high for that trend to continue. The disruption of their supply chains as a result of the outbreak in China hardly slowed down the $52.76 Billion market with a compound annual growth rate (CAGR) of between 23 and 27 percent. The biggest beneficiaries of the COVID-19 economic reset, however, would turn out to be the telemedicine and medical hardware industry in general, which alone will be worth $332 billion by 2025.
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Wine n Glass

Your phone can tell when you've been drinking!

Amelia Nichele
Cosmos Magazine
Tue, 18 Aug 2020 19:54 UTC
Pub Scene
© EXTREME-PHOTOGRAPHER / Getty Images
The best guide to whether you've had too much to drink may already be in your pocket.

Medical researchers from Stanford University, US, have trialled using a smartphone to monitor changes in our movements after we've been drinking, then deliver real-time information - which may serve as a warning or a reminder.

"We have powerful sensors we carry around with us wherever we go," says Brian Suffoletto, lead author of a paper in the Journal of Studies on Alcohol and Drugs. "We need to learn how to use them to best serve public health."

Suffoletto and colleagues invited 22 adults aged 21 to 43 to their lab and gave them a mixed drink with enough vodka to produce a breath alcohol level of 0.2%.

They then breath-tested them every hour for seven hours, each time also asking them to "walk the line" (10 steps forward and 10 back) with a smartphone fitted to their lower back.
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Info

'Time crystals' observed for the first time


Lancaster University
Mon, 17 Aug 2020 16:00 UTC
Rotating refrigerator
© Aalto University/Mikko RaskinenThe rotating refrigerator at Aalto University.
For the first time ever, scientists have witnessed the interaction of a new phase of matter known as "time crystals".

The discovery, published in Nature Materials, may lead to applications in quantum information processing because time crystals automatically remain intact - coherent - in varying conditions. Protecting coherence is the main difficulty hindering the development of powerful quantum computers.

Dr Samuli Autti, lead author from Lancaster University, said: "Controlling the interaction of two time crystals is a major achievement. Before this, nobody had observed two time crystals in the same system, let alone seen them interact.

"Controlled interactions are the number one item on the wish list of anyone looking to harness a time crystal for practical applications, such as quantum information processing."

Time crystals are different from a standard crystal - like metals or rocks - which is composed of atoms arranged in a regularly repeating pattern in space.
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Attention

Massive, growing weak spot in Earth's magnetic field about to split in two says NASA

Ilya Tsukanov
Sputnik News
Tue, 18 Aug 2020 11:57 UTC
South Atlantic Anomaly
© NASA
Geologists began expressing concerns about the magnetic field that shields Earth from deadly solar radiation in 2019, when the US National Oceanic and Atmospheric Administration was forced to update its World Magnetic Model a year early after finding that the magnetic north pole was rapidly moving out of the Canadian Arctic and toward Siberia.

The US National Aeronautics and Space Administration is tracking an immense, growing, and slowly splitting "dent" in the Earth's Magnetic field.

The area, known as the South Atlantic Anomaly, is situated in the southern hemisphere between South America and the southern Atlantic Ocean off the coast of southwestern Africa. According to recent NASA monitoring and modeling, the area is expanding westward and becoming weaker, and expected to completely split into two separate cells, each spanning thousands of kilometres across, soon.

NASA says the weakening of the magnetic field in this area threatens to allow more solar radiation to get closer to the surface of Earth, disabling electronics or scrambling or temporarily disabling satellites and other space-based man-made objects that pass through it.
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Water

Microplastic particles now discoverable in human organs

Damian Carrington
The Guardian
Mon, 17 Aug 2020 12:07 UTC
plastic waste
© Rungroj Yongrit/EPAScientists have identified chemical traces of plastic in tissue.
Microplastic and nanoplastic particles are now discoverable in human organs thanks to a new technique.

Microplastics have polluted the entire planet, from Arctic snow and Alpine soils to the deepest oceans. People are also known to consume them via food and water, and to breathe them in, but the potential impact on human health is not yet known.

The researchers expect to find the particles in human organs and have identified chemical traces of plastic in tissue. But isolating and characterising such minuscule fragments is difficult, and contamination from plastics in the air is also a challenge.

To test their technique, they added particles to 47 samples of lung, liver, spleen and kidney tissue obtained from a tissue bank established to study neurodegenerative diseases. Their results showed that the microplastics could be detected in every sample.

The scientists, whose work is being presented at a meeting of the American Chemical Society on Monday, said their technique would enable other researchers to determine contamination levels in human organs around the world.
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