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Surprising discovery in one of the universe’s oldest stars

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The primitive star is known as J0815+4729. It’s 5,000 light-years away from us in the Lynx constellation. And when astronomers used the W. M. Keck Observatory on Maunakea in Hawaii to study it, they were able to understand its chemical composition, which reveals previously unknown secrets about the earliest times in our universe.
The findings from the observation published this week in The Astrophysical Journal Letters.
An artist's illustration of the supernova explosions of the first massive stars that formed in the Milky Way.
“The primitive composition of the star indicates that it was formed during the first hundreds of millions of years after the Big Bang, possibly from the material expelled from the first supernovae of the Milky Way,” said Jonay González Hernández, lead study author and Ramón y Cajal postdoctoral researcher at the observatory.
Hydrogen and helium are the most plentiful elements in the universe. Oxygen ranks third behind those, and while we know it’s essential for life on Earth it didn’t exist when the universe began. Instead, oxygen was only created within the nuclear reactions powering massive stars that are ten times the mass of our sun. This star was formed from the first generation of stars in the universe that exploded.
This ancient north star likely helped guide the building of Egyptian pyramidsThis ancient north star likely helped guide the building of Egyptian pyramids
When they used the observatory to study the star for more than five hours over the course of one evening, they found 16 chemicals in the star’s atmosphere.
“Stars like J0815+4729 are referred to as halo stars,” said Adam Burgasser, study co-author and astrophysicist at the University of California, San Diego. “This is due to their roughly spherical distribution around the Milky Way, as opposed to the more familiar flat disk of younger stars that include the sun.”
New image reveals explosive history of Milky Way's centerNew image reveals explosive history of Milky Way's center
The chemical composition was strange, including unexpectedly large amounts of carbon, nitrogen and oxygen that were ten, eight and three percent of the abundance found in our sun.
“Only a few such stars are known in the halo of our galaxy, but none have such an enormous amount of carbon, nitrogen and oxygen compared to their iron content,” said David Aguado, study co-author and postdoctoral researcher at the University of Cambridge.
Ancient star discovery sheds light on Big Bang mysteryAncient star discovery sheds light on Big Bang mystery
“This result is very exciting. It tells us about some of the earliest times in the universe by using stars in our cosmic back yard,” said John O’Meara, the Keck Observatory’s chief scientist. “I look forward to seeing more measurements like this one so we can better understand the earliest seeding of oxygen and other elements throughout the young universe.”
The research also highlights the importance of stellar mapping and analysis to find these old, rare stars, like the Sloan Digital Sky Survey, which helped create one of the most detailed 3D maps of the universe. The team with the Instituto de Astrofísica de Canarias, or IAC, helped characterize the star in 2017, using the Grand Canary Telescope in La Palma, Spain.
“Thirty years ago, we started at the IAC to study the presence of oxygen in the oldest stars of the galaxy; those results had already indicated that this element was produced enormously in the first generations of supernovae. However, we could not imagine that we would find a case of enrichment as spectacular as that of this star,” said Rafael Rebolo, study co-author and IAC director.

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Scientists revive 48500-year-old ‘zombie virus’ buried in ice

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The thawing of ancient permafrost due to climate change may pose a new threat to humans, according to researchers who revived nearly two dozen viruses – including one frozen under a lake more than 48,500 years ago.

European researchers examined ancient samples collected from permafrost in the Siberia region of Russia. They revived and characterized 13 new pathogens, what they termed “zombie viruses,” and found that they remained infectious despite spending many millennia trapped in the frozen ground.

Scientists have long warned that the thawing of permafrost due to atmospheric warming will worsen climate change by freeing previously trapped greenhouse gases like methane. But its effect on dormant pathogens is less well understood.

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The team of researchers from Russia, Germany and France said the biological risk of reanimating the viruses they studied was “totally negligible” due to the strains they targeted, mainly those capable of infecting amoeba microbes. The potential revival of a virus that could infect animals or humans is much more problematic, they said, warning that their work can be extrapolated to show the danger is real.

“It is thus likely that ancient permafrost will release these unknown viruses upon thawing,” they wrote in an article posted to the preprint repository bioRxiv that hasn’t yet been peer-reviewed.

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“How long these viruses could remain infectious once exposed to outdoor conditions, and how likely they will be to encounter and infect a suitable host in the interval, is yet impossible to estimate.”

“But the risk is bound to increase in the context of global warming when permafrost thawing will keep accelerating, and more people will be populating the Arctic in the wake of industrial ventures,” they said.

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McMaster University team to finalize plans with CSA on deployment of satellite

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A team of students from McMaster University which has spent close to seven years creating a satellite to measure space radiation is set to finalize plans to deploy the device in outer space.

The Canadian Space Agency (CSA) is welcoming the developers this week to finalize preparation of their CubeSat, a miniaturized satellite to further the understanding of long-term exposure to space radiation.

Operation Team Lead with McMaster’s NEUtron DOSimetry & Exploration (NEUDOSE) mission Taren Ginter says the idea was selected for the Canadian Cube Sat project in 2018. In simple terms, Ginter says it measures the effects of ionizing radiation on the human body.

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Some of the financial backing for the project came in the form of $200,000 awarded to the McMaster developers by the CSA.

Ginter says as spaceflight and deep-space missions become a reality in the future, astronauts will likely have to face radiation that is distinct from the radiation experienced on earth.

The question the NEUDOSE mission is looking to answer is what kind and how much radiation astronauts will face on a multi-year mission in space.

“So our goal is to get a sense of those radiation differences and hopefully we can implement better safety precautions so that astronauts are protected,” Ginter explained.

The McMaster radiation detector is the size of a loaf of bread and is expected to be placed in a small satellite prior to being deployed into space, free floating like an astronaut would.

If it works properly, the device will send real-time radiation measurements back to the team at the university.

The device is the concept of Dr. Andrei Hanu, who came up with the idea while working at NASA as a research scientist.

Hanu led the first team of developers in 2015, jokingly referring to the device as the “igloo” due to its top which is dome-shaped.

However, Ginter says the satellite will actually look like a bunch of solar panels connected together due to the fact it needs to be charged by sunlight.

“But inside of the satellite, we have our charged and neutral particle tissue equivalent proportional counter, which is quite a mouthful,” Ginter said.

“So this is the actual payload of our satellite that will be looking at the radiation in low-earth orbit and then sending that information back down to ground station at McMaster.”

The NEUDOSE CubeSat will head to the CSA this week for a final step confirming it meets standards to be deployed from the International Space Station (ISS).

The life expectancy of the device is approximately one year in the Earth’s orbit after it’s been deployed.

The McMaster creation is earmarked for the ISS in February following launch from a SpaceX Dragon ship in Florida.

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Explainable AI-based physical theory for advanced materials design: Scientists develop an ‘extended Landau free energy model’ for causal analysis and visualization in nano-magnetic devices with AI and topology

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Microscopic materials analysis is essential to achieve desirable performance in next-generation nanoelectronic devices, such as low power consumption and high speeds. However, the magnetic materials involved in such devices often exhibit incredibly complex interactions between nanostructures and magnetic domains. This, in turn, makes functional design challenging.

Traditionally, researchers have performed a visual analysis of the microscopic image data. However, this often makes the interpretation of such data qualitative and highly subjective. What is lacking is a causal analysis of the mechanisms underlying the complex interactions in nanoscale magnetic materials.

In a recent breakthrough published in Scientific Reports, a team of researchers led by Prof. Masato Kotsugi from Tokyo University of Science, Japan succeeded in automating the interpretation of the microscopic image data. This was achieved using an “extended Landau free energy model” that the team developed using a combination of topology, data science, and free energy. The model could illustrate the physical mechanism as well as the critical location of the magnetic effect, and proposed an optimal structure for a nano device. The model used physics-based features to draw energy landscapes in the information space, which could be applied to understand the complex interactions at the nanoscales in a wide variety of materials.

“Conventional analysis are based on a visual inspection of microscope images, and the relationships with the material function are expressed only qualitatively, which is a major bottleneck for material design. Our extended Landau free energy model enables us to identify the physical origin and location of the complex phenomena within these materials. This approach overcomes the explainability problem faced by deep learning, which, in a way, amounts to reinventing new physical laws,” Prof. Kotsugi explains. This work was supported by KAKENHI, JSPS, and the MEXT-Program for Creation of Innovative Core Technology for Power Electronics Grant.

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When designing the model, the team made use of the state-of-art technique in the fields of topology and data science to extend the Landau free energy model. This led to a model that enabled a causal analysis of the magnetization reversal in nanomagnets. The team then carried out an automated identification of the physical origin and visualization of the original magnetic domain images.

Their results indicated that the demagnetization energy near a defect gives rise to a magnetic effect, which is responsible for the “pinning phenomenon.” Further, the team could visualize the spatial concentration of energy barriers, a feat that had not been achieved until now. Finally, the team proposed a topologically inverse design of recording devices and nanostructures with low power consumption.

The model proposed in this study is expected to contribute to a wide range of applications in the development of spintronic devices, quantum information technology, and Web 3.

“Our proposed model opens up new possibilities for optimization of magnetic properties for material engineering. The extended method will finally allow us to clarify ‘why’ and ‘where’ the function of a material is expressed. The analysis of material functions, which used to rely on visual inspection, can now be quantified to make precise functional design possible,” concludes an optimistic Prof. Kotsugi.

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