‘Black dwarf supernova’: Physicist calculates when the last supernova ever will happen

The end of the universe as we know it will not come with a bang. Most stars will very, very slowly fizzle as their temperatures fade to zero.

“It will be a bit of a sad, lonely, cold place,” said theoretical physicist Matt Caplan, who added no one will be around to witness this long farewell happening in the far far future. Most believe all will be dark as the universe comes to an end. “It’s known as ‘heat death,’ where the universe will be mostly black holes and burned-out stars,” said Caplan, who imagined a slightly different picture when he calculated how some of these dead stars might change over the eons.

Punctuating the darkness could be silent fireworks — explosions of the remnants of stars that were never supposed to explode. New theoretical work by Caplan, an assistant professor of physics at Illinois State University, finds that many white dwarfs may explode in supernova in the distant far future, long after everything else in the universe has died and gone quiet.

In the universe now, the dramatic death of massive stars in supernova explosions comes when internal nuclear reactions produce iron in the core. Iron cannot be burnt by stars — it accumulates like a poison, triggering the star’s collapse creating a supernova. But smaller stars tend to die with a bit more dignity, shrinking and becoming white dwarfs at the end of their lives.

“Stars less than about 10 times the mass of the sun do not have the gravity or density to produce iron in their cores the way massive stars do, so they can’t explode in a supernova right now,” said Caplan. “As white dwarfs cool down over the next few trillion years, they’ll grow dimmer, eventually freeze solid, and become ‘black dwarf’ stars that no longer shine.” Like white dwarfs today, they’ll be made mostly of light elements like carbon and oxygen and will be the size of the Earth but contain about as much mass as the sun, their insides squeezed to densities millions of times greater than anything on Earth.

But just because they’re cold doesn’t mean nuclear reactions stop. “Stars shine because of thermonuclear fusion — they’re hot enough to smash small nuclei together to make larger nuclei, which releases energy. White dwarfs are ash, they’re burnt out, but fusion reactions can still happen because of quantum tunneling, only much slower, Caplan said. “Fusion happens, even at zero temperature, it just takes a really long time.” He noted this is the key for turning black dwarfs into iron and triggering a supernova.

Caplan’s new work, accepted for publication by Monthly Notices of the Royal Astronomical Society, calculates how long these nuclear reactions take to produce iron, and how much iron black dwarfs of different sizes need to explode. He calls his theoretical explosions “black dwarf supernova” and calculates that the first one will occur in about 10 to the 1100th years. “In years, it’s like saying the word ‘trillion’ almost a hundred times. If you wrote it out, it would take up most of a page. It’s mindbogglingly far in the future.”

Of course, not all black dwarfs will explode. “Only the most massive black dwarfs, about 1.2 to 1.4 times the mass of the sun, will blow.” Still, that means as many as 1 percent of all stars that exist today, about a billion trillion stars, can expect to die this way. As for the rest, they’ll remain black dwarfs. “Even with very slow nuclear reactions, our sun still doesn’t have enough mass to ever explode in a supernova, even in the far far future. You could turn the whole sun to iron and it still wouldn’t pop.”

Caplan calculates that the most massive black dwarfs will explode first, followed by progressively less massive stars, until there are no more left to go off after about 1032000 years. At that point, the universe may truly be dead and silent. “It’s hard to imagine anything coming after that, black dwarf supernova might be the last interesting thing to happen in the universe. They may be the last supernova ever.” By the time the first black dwarfs explode, the universe will already be unrecognizable. “Galaxies will have dispersed, black holes will have evaporated, and the expansion of the universe will have pulled all remaining objects so far apart that none will ever see any of the others explode.It won’t even be physically possible for light to travel that far.”

Even though he’ll never see one, Caplan remains unbothered. “I became a physicist for one reason. I wanted to think about the big questions- why is the universe here, and how will it end?” When asked what big question comes next, Caplan says, “Maybe we’ll try simulating some black dwarf supernova. If we can’t see them in the sky then at least we can see them on a computer.”

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Representation Matters

Representation matters! But if you haven’t thought about it before, it can be hard to know how to help. If you live every day as a marginalized person, it can be hard to find resources to support you. So, here are a few places to start.

Whether you’re looking for speakers for your conference, a cofounder for your next robotics startup, or just cool and inspiring people to follow – check out these resources supporting Black scientists, engineers, and other STEM specialists.




New study provides maps, ice favorability index to companies looking to mine the moon

The 49ers who panned for gold during California’s Gold Rush didn’t really know where they might strike it rich. They had word of mouth and not much else to go on.

Researchers at the University of Central Florida want to give prospectors looking to mine the moon better odds of striking gold, which on the moon means rich deposits of water ice that can be turned into resources, like fuel, for space missions.

A team lead by planetary scientist Kevin Cannon created an Ice Favorability Index. The geological model explains the process for ice formation at the poles of the moon, and mapped the terrain, which includes craters that may hold ice deposits. The model, which has been published in the peer-reviewed journal Icarus, accounts for what asteroid impacts on the surface of the moon may do to deposits of ice found meters beneath the surface.

“Despite being our closest neighbor, we still don’t know a lot about water on the moon, especially how much there is beneath the surface,” Cannon says. “It’s important for us to consider the geologic processes that have gone on to better understand where we may find ice deposits and how to best get to them with the least amount of risk.”

The team was inspired by mining companies on Earth, which conduct detailed geological work, and take core samples before investing in costly extraction sites. Mining companies conduct field mappings, take core samples from the potential site and try to understand the geological reasons behind the formation of the particular mineral they are looking for in an area of interest. In essence they create a model for what a mining zone might look like before deciding to plunk down money to drill.

The team at UCF followed the same approach using data collected about the moon over the years and ran simulations in the lab. While they couldn’t collect core samples, they had data from satellite observations and from the first trip to the moon.

Why Mine the Moon

In order for humans to explore the solar system and beyond, spacecraft have to be able to launch and continue on their long missions. One of the challenges is fuel. There are no gas stations in space, which means spacecraft have to carry extra fuel with them for long missions and that fuel weighs a lot. Mining the moon could result in creating fuel , which would help ease the cost of flights since spacecraft wouldn’t have to haul the extra fuel.

Water ice can be purified and processed to produce both hydrogen and oxygen for propellent, according to several previously published studies. Sometime in the future, this process could be completed on the moon effectively producing a gas station for spacecraft. Asteroids may also provide similar resources for fuel.

Some believe a system of these “gas stations” would be the start of the industrialization of space.

Several private companies are exploring mining techniques to employ on the moon. Both Luxembourg and the United States have adopted legislation giving citizens and corporations ownership rights over resources mined in space, including the moon, according to the study.

“The idea of mining the moon and asteroids isn’t science fiction anymore,” says UCF physics Professor and co-author Dan Britt. “There are teams around the world looking to find ways to make this happen and our work will help get us closer to making the idea a reality.”

The study was supported by NASA’s Solar System Exploration Research Virtual Institute cooperative agreement with the Center for Lunar and Asteroid Surface Science (CLASS) based at UCF.

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Materials provided by University of Central Florida. Original written by Zenaida Gonzalez Kotala. Note: Content may be edited for style and length.

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Removing the novel coronavirus from the water cycle

Scientists know that coronaviruses, including the SARS-CoV-19 virus responsible for the COVID-19 pandemic, can remain infectious for days — or even longer — in sewage and drinking water.

Two researchers, Haizhou Liu, an associate professor of chemical and environmental engineering at the University of California, Riverside; and Professor Vincenzo Naddeo, director of the Sanitary Environmental Engineering Division at the University of Salerno, have called for more testing to determine whether water treatment methods are effective in killing SARS-CoV-19 and coronaviruses in general.

The virus can be transported in microscopic water droplets, or aerosols, which enter the air through evaporation or spray, the researchers wrote in an editorial for Environmental Science: Water Research & Technology, a leading environmental journal of the Royal Society of Chemistry in the United Kingdom.

“The ongoing COVID-19 pandemic highlights the urgent need for a careful evaluation of the fate and control of this contagious virus in the environment,” Liu said. “Environmental engineers like us are well positioned to apply our expertise to address these needs with international collaborations to protect public health.”

During a 2003 SARS outbreak in Hong Kong, a sewage leak caused a cluster of cases through aerosolization. Though no known cases of COVID-19 have been caused by sewage leaks, the novel coronavirus is closely related to the one that causes SARS, and infection via this route could be possible.

The novel coronavirus could also colonize biofilms that line drinking water systems, making showerheads a possible source of aerosolized transmission. This transmission pathway is thought to be a major source of exposure to the bacteria that causes Legionnaire’s disease, for example.

Fortunately, most water treatment routines are thought to kill or remove coronaviruses effectively in both drinking and wastewater. Oxidation with hypochlorous acid or peracetic acid, and inactivation by ultraviolet irradiation, as well as chlorine, are thought to kill coronaviruses. In wastewater treatment plants that use membrane bioreactors, the synergistic effects of beneficial microorganisms and the physical separation of suspended solids filter out viruses concentrated in the sewage sludge.

Liu and Naddeo caution, however, that most of these methods have not been studied for effectiveness specifically on SARS-CoV-19 and other coronaviruses, and they have called for additional research.

They also suggest upgrading existing water and wastewater treatment infrastructure in outbreak hot spots, which possibly receive coronavirus from places such as hospitals, community clinics, and nursing homes. For example, energy-efficient, light-emitting, diode-based, ultraviolet point-of-use systems could disinfect water before it enters the public treatment system.

Potable water-reuse systems, which purify wastewater back into tap water, also need thorough investigation for coronavirus removal, and possibly new regulatory standards for disinfection, the researchers wrote.

The extent to which viruses can colonize biofilms is also not yet known. Biofilms are thin, slimy bacterial growths that line the pipes of many aging drinking water systems. Better monitoring of coronaviruses in biofilms might be necessary to prevent outbreaks.

The surge in household use of bactericides, virucides and disinfectants will probably cause an increase of antibiotic-resistant bacteria in the environment. Treated wastewater discharged into natural waterways demands careful monitoring through the entire water cycle. Liu and Naddeo call on chemists, environmental engineers, microbiologists, and public health specialists to develop multidisciplinary and practical solutions for safe drinking water and healthy aquatic environments.

Lastly, developing countries and some regions within highly developed nations, such as rural and impoverished communities, which lack the basic infrastructure to remove other common contaminants might not be able to remove SARS-CoV-19 either. These places might experience frequent COVID-19 outbreaks that spread easily through globalized trade and travel. Liu and Naddeo suggest governments of developed countries must support and finance water and sanitation systems wherever they are needed.

“It is now clear to all that globalization also introduces new health risks. Where water and sanitation systems are not adequate, the risk of finding novel viruses is very high,” Naddeo said. “In a responsible and ideal scenario, the governments of developed countries must support and finance water and sanitation systems in developing countries, in order to also protect the citizens of their own countries.”

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Quantum effect triggers unusual material expansion

You know how you leave space in a water bottle before you pop it in the freezer — to accommodate the fact that water expands as it freezes? Most metal parts in airplanes face the more common opposite problem. At high altitudes (low temperatures) they shrink. To keep such shrinkage from causing major disasters, engineers make airplanes out of composites or alloys, mixing materials that have opposite expansion properties to balance one another out.

New research conducted in part at the U.S. Department of Energy’s Brookhaven National Laboratory may bring a whole new class of chemical elements into this materials science balancing act.

As described in a paper just published in the journal Physical Review Letters, scientists used x-rays at Brookhaven’s National Synchrotron Light Source II (NSLS-II) — a U.S. Department of Energy Office of Science user facility — and two other synchrotron light sources to explore an unusual metal that expands dramatically at low temperature. The experiments on samarium sulfide doped with some impurities revealed details about the material’s atomic-level structure and the electron-based origins of its “negative thermal expansion.”

This work opens avenues for designing new materials where the degree of expansion can be precisely tuned by tweaking the chemical recipe. It also suggests a few related materials that could be explored for metal-mixing applications.

“In practical applications, whether an airplane or an electronic device, you want to make alloys of materials with these opposite properties — things that expand on one side and shrink on the other when they cool down, so in total it stays the same,” explained Daniel Mazzone, the paper’s lead author and a postdoctoral fellow at NSLS-II and Brookhaven Lab’s Condensed Matter Physics and Materials Science Department.

But materials that mimic water’s expansion when chilled are few and far between. And while the expansion of freezing water is well understood, the dramatic expansion of samarium sulfide had never been explained.

Like other materials Mazzone has studied, this samarium-based compound (specifically samarium sulfide with some yttrium atoms taking the place of a few samarium atoms) is characterized by competing electronic phases (somewhat analogous to the solid, liquid, and gaseous phases of water). Depending on external conditions such as temperature and pressure, electrons in the material can do different things. In some cases, the material is a gold-colored metal through which electrons can move freely — a conductor. In other conditions, it’s a black-colored semiconductor, allowing only some electrons to flow.

The golden metallic state is the one that expands dramatically when chilled, making it an extremely unusual metal. Mazzone and his colleagues turned to x-rays and theoretical descriptions of the electrons’ behavior to figure out why.

At NSLS-II’s Pair Distribution Function (PDF) beamline, the scientists conducted diffraction experiments. The PDF beamline is optimized for studies of strongly correlated materials under a variety of external conditions such as low temperatures and magnetic fields. For this experiment, the team placed samples of their samarium metal inside a liquid-helium-cooled cryostat in the beam of NSLS-II’s x-rays and measured how the x-rays bounced off atoms making up the material’s crystal structure at different temperatures.

“We track how the x-rays bounce off the sample to identify the locations of atoms and the distances between them,” said Milinda Abeykoon, the lead scientist of the PDF beamline. “Our results show that, as the temperature drops, the atoms of this material move farther apart, causing the entire material to expand up to three percent in volume.”

The team also used x-rays at the SOLEIL synchrotron in France and SPring-8 synchrotron in Japan to take a detailed look at what electrons were doing in the material at different stages of the temperature-induced transition.

“These ‘x-ray absorption spectroscopy’ experiments can track whether electrons are moving into or out of the outermost ‘shell’ of electrons around the samarium atoms,” explained co-corresponding author Ignace Jarrige, a physicist at NSLS-II.

If you think back to one of the basics of chemistry, you might remember that atoms with unfilled outer shells tend to be the most reactive. Samarium’s outer shell is just under half full.

“All the physics is essentially contained in this last shell, which is not full or not empty,” Mazzone said.

The electron-tracking x-ray experiments revealed that electrons flowing through the samarium-sulfide metal were moving into that outer shell around each samarium atom. As each atom’s electron cloud grew to accommodate the extra electrons, the entire material expanded.

But the scientists still had to explain the behavior based on physics theories. With the help of calculations performed by Maxim Dzero, a theoretical physicist from Kent State University, they were able to explain this phenomenon with the so-called Kondo effect, named after physicist Jun Kondo.

The basic idea behind the Kondo effect is that electrons will interact with magnetic impurities in a material, aligning their own spins in the opposite direction of the larger magnetic particle to “screen out,” or cancel, its magnetism.

In the samarium-sulfide material, Dzero explained, the almost-half-full outer shell of each samarium atom acts as a tiny magnetic impurity pointing in a certain direction. “And because you have a metal, you also find free electrons that can approach and cancel out these little magnetic moments,” Dzero said.

Not all elements subject to the Kondo effect have electrons fill the outermost shell, as it can also go the other way — causing electrons to leave the shell. The direction is determined by a delicate energy balance dictated by the rules of quantum mechanics.

“For some elements, because of the way the outer shell fills up, it is more energetically favorable for electrons to move out of the shell. But for a couple of these materials, the electrons can move in, which leads to expansion,” Jarrige said. In addition to samarium, the other two elements are thulium and ytterbium.

It would be worth exploring compounds containing these other elements as additional possible ingredients for creating materials that expand upon cooling, Jarrige said.

Finally, the scientists noted that the extent of the negative thermal expansion in samarium sulfide can be tuned by varying the concentration of impurities.

“This tunability makes this material very valuable for engineering expansion-balanced alloys,” Mazzone said.

“The application of highly developed many-body theory modeling was an important part of the work to identify the connection between the magnetic state of this material and its volume expansion,” said Jason Hancock, a collaborator at the University of Connecticut (UConn). “This collaboration between Kent State, UConn, Brookhaven Lab, partner synchrotrons, and synthesis groups in Japan could potentially guide new materials discovery efforts that make use of the unusual properties of these rare-earth materials.”

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10 Top Coupons APIs

Retailers and ecommerce providers know that coupons are effective marketing tools for engaging customers and building loyalty to brands. Developers who create applications that are wishing to cash in on the coupon craze can look to ProgrammableWeb to find the best Application Programming Interfaces, or APIs, to distribute coupons, rewards, promo codes and vouchers.

The Coupons category on ProgrammableWeb provides scores of resources for developers including APIs for coupon distribution, coupon data, coupon campaigns, membership programs, daily deals, coupon aggregation, rebates, referrals, coupon management, and many more.

This article highlights the ten most popular APIs for creating Coupons functions in applications, based on web page visits on ProgrammableWeb.

1. Groupon API

Groupon features a daily deal on the best stuff to do, see, eat, and buy in a variety of cities across the United States. Groupon gets discounts you won’t find anywhere else through the power of group buying. The Groupon APITrack this API enables applications to directly interact with Groupon via a REST API, providing data results based on location, deal type, channels and categories.

2. Discount API

The Discount APITrack this API allows developers to include interesting local deals and discounts on their app or website. These deals come from a variety of sources to ensure that there are options appropriate for many different audiences, and developers can choose what kinds of deals they want to be displayed using a web interface. Deals that match the user’s location can be retrieved using the user’s IP address, GPS coordinates, or street address.

3. Information Machine API

The Information Machine APITrack this API automatically & passively collects users’ purchase data from online and loyalty card purchases at most healthcare, grocery, takeout and major stores (such as Amazon, Costco, Target, Walmart, Walgreens, etc.). The API connects this raw purchase data to product and pricing data. An example of a use case could be a developer can create a food or dieting application that remembers everything the user purchased to make food logging easier. Or the developer can add coupon recommendations based on a user’s past purchasing data.

4. Overstock Shopping API

Overstock is an online retailer based in Salt Lake City. The Overstock Shopping APITrack this API provides CMSP (Channel Management Service Provider) applications with a retail database. The Shopping API returns details on several types of data include product status, order processing, cancellations, and returns.

5. Vouchery API

Vouchery is a coupon and promotion automation APITrack this API. Developers can use it to run promotional campaigns, use coupons, add loyalty point services, retrieve customers’ behavioral information, and more. The service includes an engine to define rules based on basket data, customer history or anything else, and give different types of rewards to customers.

Create personalized discounts via Vouchery API. Screenshot: Vouchery

6. OfferDaddy API

OfferDaddy is a mobile or website “offer wall” of discounts earned by users for taking surveys, installing apps, taking quizzes or or other actions. The OfferDaddy APITrack this API returns monetization features like coupons, surveys, videos, and tasks data to implement into mobile applications. API responses in JSON format include tracking link, amount, image URL, countries, categories, and devices.

7. Talon.One API

Talon.One promotion engine enables users to create and manage coupon codes, discounts, loyalty programs, referral rewards, and product bundlings in one system. The Talon.One APITrack this API includes the Integration endpoint to create customer profiles, track actions with custom events, and more; plus the Management endpoint, which returns all information about user applications, campaigns, rulesets, and attributes. Targeted industries are eCommerce, eSports, marketplace, telecommunication, travel, car rental, and airlines.

8. 8coupons API

8coupons brings together all the deals from neighborhood restaurants, bars, salons, and stores so that users can find the best deals nearby. The 8coupons APITrack this API gives developers access to the full feature set of the 8coupons site. The API provides methods such as retrieving dealer types, getting deals by location, getting deals by store ID and more. Developers must sign up and pay up front for access.

9. Coupomated Coupon DataFeed API

The Coupomated Coupon DataFeed REST APITrack this API is an automated coupon content distribution platform based in India. It provides coupon website development, price comparison website, & affiliate products from 2000+ Indian merchants.

10. PassKit API

PassKit is a pass and ticket generator for Apple Wallet and Google Pay. PassKit offers templates and designs for event tickets, coupons, giftcards, and boarding passes. The PassKit API allows developers to access and integrate the functionality of PassKit with PassBook and other applications.

Find more than 105 APIs, 35 SDKs, and 38 Source Code samples in the Coupons category.

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Author: <a href="">joyc</a>


March’s DC-Area API Meetup to Feature Talks on Serverless, Big Parser APIs, and APIs 101 (Part 3)

We know it’s not officially Spring yet. But Spring is definitely in the air. And so is March’s DC-Area API Meetup which will be taking place on Tuesday, March 3, 2020 (one week from tomorrow) at 6pm near Dupont Circle in Washington, DC.

This month, in addition to my presentation of Part 3 of my long running (and updated) API 101 series, Balvinder Singh from Walmart Labs will be talking about serverless backends using BigParser APIs.

Serverless technology could very well be the 2nd generation of the cloud. Do you remember when Amazon launched the idea of Amazon Web Services based on the idea that, through APIs, you could provision and deprovision servers on the fly and only pay for the number of servers that you’re using over a given period of time? Well, serverless technology is like that, but on a completely different level.

That’s because instead of wastefully provisioning an entire server on the fly when you suddenly need more compute power, you essentially only provision the exact compute resources that you need (basically, a tiny fraction of an entire server) at the exact moment you need them on the same pay as you go basis. Thus, “serverless.”  This not only makes it easier to scale your back-end infrastructure based on actual compute requirements, you’re also never paying for an underutilized server (you know? that entire server you had to provision just to handle a little task?).

So, hearing how Balvinder and his colleagues at Walmart Labs are thinking about serverless technology is a pretty big deal for anyone looking to help make smart, innovative technology decisions at their job.

Of course, the networking will be great and you’ll get a chance to eat Github’s pizza since Github is this month’s pizza sponsor. U.Group will of course be providing the venue and the beverages so be sure to RSVP so we can plan for enough food for everyone.

If you live in the Washington, DC area (or will be in the neighborhood on March 3, 2020) and want to rub shoulders with other members of the local API community (or you just want to get smart about APIs), then this is the right meetup to come to. So, I hope to see you there!

Finally, as always, we are very grateful to the meetup’s enduring sponsors for making our monthly gatherings possible; the U.Group for providing the beverages and the venue and then, Github, and MuleSoft who take turns buying the pizza. If you are interested in becoming a sponsor of the meetup, feel free to reach out to me at [email protected]. 

OK, I hope to see you there!!

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Author: <a href="">david_berlind</a>


Will the future’s super batteries be made of seawater?

We all know the rechargeable and efficient lithium ion (Li-ion) batteries sitting in our smartphones, laptops and also in electric cars.

Unfortunately, lithium is a limited resource, so it will be a challenge to satisfy the worlds’ growing demand for relatively cheap batteries. Therefore, researchers are now looking for alternatives to the Li-ion battery.

A promising alternative is to replace lithium with the metal sodium — to make Na-ion batteries. Sodium is found in large quantities in seawater and can be easily extracted from it.

“The Na-ion battery is still under development, and researchers are working on increasing its service life, lowering its charging time and making batteries that can deliver many watts,” says research leader Dorthe Bomholdt Ravnsbæk of the Department of Physics, Chemistry and Pharmacy at University of Southern Denmark.

She and her team are preoccupied with developing new and better rechargeable batteries that can replace todays’ widely used Li-ion batteries.

For the Na-ion batteries to become an alternative, better electrode materials must be developed — something she and colleagues from the University of Technology and the Massachusetts Institute of Technology, USA, have looked at in a new study published in the journal ACS Applied Energy Materials.

But before looking at the details of this study, let’s take a look at why the Na-ion battery has the potential to become the next big battery success.

“An obvious advantage is that sodium is a very readily available resource, which is found in very large quantities in seawater. Lithium, on the other hand, is a limited resource that is mined only in a few places in the world,” explains Dorthe Bomholdt Ravnsbæk.

Another advantage is that Na-ion batteries do not need cobalt, which is still needed in Li-ion batteries. The majority of the cobalt used today to make Li-ion batteries, is mined in the Democratic Republic of Congo, where rebellion, disorganized mining and child labor create uncertainty and moral qualms regarding the country’s cobalt trade.

It also counts on the plus side that Na-ion batteries can be produced at the same factories that make Li-ion batteries today.

In their new study, Dorthe Bomholdt Ravnsbæk and her colleagues have investigated a new electrode material based on iron, manganese and phosphorus.

The new thing about the material is the addition of the element manganese, which not only gives the battery a higher voltage (volts), but also increases the capacity of the battery and is likely to deliver more watts. This is because the transformations that occur at the atomic level during the discharge and charge are significantly changed by the presence of manganese.

“Similar effects have been seen in Li-ion batteries, but it is very surprising that the effect is retained in a Na-ion battery, since the interaction between the electrode and Na-ions is very different from that of Li-ions,” says Dorthe Bomholdt Ravnsbæk.

She will not try and predict when we can expect to find seawater-based Na-ion batteries in our phones and electric cars, because there are still some challenges to be solved.

One challenge is that it can be difficult to make small Na-ion batteries. But large batteries also have value — for example, when it comes to storing wind or solar energy.

Thus, in 2019, such a gigantic 100 kWh Na-ion battery was inaugurated to be tested by Chinese scientists at the Yangtze River Delta Physics Research Center. The giant battery consists of more than 600 connected Na-ion battery cells, and it supplies power to the building that houses the center. The current stored in the battery is surplus current from the main grid.

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Astronomers reveal interstellar thread of one of life’s building blocks

Phosphorus, present in our DNA and cell membranes, is an essential element for life as we know it. But how it arrived on the early Earth is something of a mystery. Astronomers have now traced the journey of phosphorus from star-forming regions to comets using the combined powers of ALMA and the European Space Agency’s probe Rosetta. Their research shows, for the first time, where molecules containing phosphorus form, how this element is carried in comets, and how a particular molecule may have played a crucial role in starting life on our planet.

“Life appeared on Earth about 4 billion years ago, but we still do not know the processes that made it possible,” says VĂ­ctor Rivilla, the lead author of a new study published today in the journal Monthly Notices of the Royal Astronomical Society. The new results from the Atacama Large Millimeter/Submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, and from the ROSINA instrument on board Rosetta, show that phosphorus monoxide is a key piece in the origin-of-life puzzle.

With the power of ALMA, which allowed a detailed look into the star-forming region AFGL 5142, astronomers could pinpoint where phosphorus-bearing molecules, like phosphorus monoxide, form. New stars and planetary systems arise in cloud-like regions of gas and dust in between stars, making these interstellar clouds the ideal places to start the search for life’s building blocks.

The ALMA observations showed that phosphorus-bearing molecules are created as massive stars are formed. Flows of gas from young massive stars open up cavities in interstellar clouds. Molecules containing phosphorus form on the cavity walls, through the combined action of shocks and radiation from the infant star. The astronomers have also shown that phosphorus monoxide is the most abundant phosphorus-bearing molecule in the cavity walls.

After searching for this molecule in star-forming regions with ALMA, the European team moved on to a Solar System object: the now-famous comet 67P/Churyumov-Gerasimenko. The idea was to follow the trail of these phosphorus-bearing compounds. If the cavity walls collapse to form a star, particularly a less-massive one like the Sun, phosphorus monoxide can freeze out and get trapped in the icy dust grains that remain around the new star. Even before the star is fully formed, those dust grains come together to form pebbles, rocks and ultimately comets, which become transporters of phosphorus monoxide.

ROSINA, which stands for Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, collected data from 67P for two years as Rosetta orbited the comet. Astronomers had found hints of phosphorus in the ROSINA data before, but they did not know what molecule had carried it there. Kathrin Altwegg, the Principal Investigator for Rosina and an author in the new study, got a clue about what this molecule could be after being approached at a conference by an astronomer studying star-forming regions with ALMA: “She said that phosphorus monoxide would be a very likely candidate, so I went back to our data and there it was!”

This first sighting of phosphorus monoxide on a comet helps astronomers draw a connection between star-forming regions, where the molecule is created, all the way to Earth.

“The combination of the ALMA and ROSINA data has revealed a sort of chemical thread during the whole process of star formation, in which phosphorus monoxide plays the dominant role,” says Rivilla, who is a researcher at the Arcetri Astrophysical Observatory of INAF, Italy’s National Institute for Astrophysics.

“Phosphorus is essential for life as we know it,” adds Altwegg. “As comets most probably delivered large amounts of organic compounds to the Earth, the phosphorus monoxide found in comet 67P may strengthen the link between comets and life on Earth.”

This intriguing journey could be documented because of the collaborative efforts between astronomers. “The detection of phosphorus monoxide was clearly thanks to an interdisciplinary exchange between telescopes on Earth and instruments in space,” says Altwegg.

Leonardo Testi, ESO astronomer and ALMA European Operations Manager, concludes: “Understanding our cosmic origins, including how common the chemical conditions favourable for the emergence of life are, is a major topic of modern astrophysics. While ESO and ALMA focus on the observations of molecules in distant young planetary systems, the direct exploration of the chemical inventory within our Solar System is made possible by ESA missions, like Rosetta. The synergy between world leading ground-based and space facilities, through the collaboration between ESO and ESA, is a powerful asset for European researchers and enables transformational discoveries like the one reported in this paper.”

This research was presented in a paper to appear in Monthly Notices of the Royal Astronomical Society.

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Materials provided by ESO. Note: Content may be edited for style and length.

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IEEE Spectrum

Researchers Can Make AI Forget You

Whether you know it or not, you’re feeding artificial intelligence algorithms. Companies, governments, and universities around the world train machine learning software on unsuspecting citizens’ medical records, shopping history, and social media use. Sometimes the goal is to draw scientific insights, and other times it’s to keep tabs on suspicious individuals. Even AI models that abstract from data to draw conclusions about people in general can be prodded in such a way that individual records fed into them can be reconstructed. Anonymity dissolves.

To restore some amount of privacy, recent legislation such as Europe’s General Data Protection Regulation and the California Consumer Privacy Act provides a right to be forgotten. But making a trained AI model forget you often requires retraining it from scratch with all the data but yours. This process that can take weeks of computation.

Two new papers offer ways to delete records from AI models more efficiently, possibly saving megawatts of energy and making compliance more attractive. “It seemed like we needed some new algorithms to make it easy for companies to actually cooperate, so they wouldn’t have an excuse to not follow these rules,” said Melody Guan, a computer scientist at Stanford and co-author of the first paper.