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NASA is slamming a spacecraft into an asteroid on Monday to test planetary defence – CBC.ca

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On Monday, in what seems like a scene out of a science fiction movie, NASA will slam a spacecraft into a distant asteroid to see whether it can nudge its orbit — all in an effort to test a way to protect Earth from any potential future threats.

The good news is that there’s no need to panic: The asteroid, which is part of a binary — or two-bodied — system, is not a threat to our planet, and there are no known ones that are headed our way for at least the next 100 years. However, space agencies like the U.S. National Aeronautics and Space Administration want to be prepared should there ever be a threat.

NASA’s Double Asteroid Redirection Test (DART) is testing a way in which a spacecraft may be able to nudge an asteroid on a collision course with Earth out of its orbit.

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At 7:14 p.m. ET on Monday, the refrigerator-sized spacecraft will plunge itself into Dimorphos — a moonlet that orbits its larger companion, Didymos — at roughly 6.6 km/s.

The goal isn’t to knock Dimorphos out of orbit but rather to change its 12-hour orbit around Didymos by 10 minutes. This means that scientists will know within roughly 12 hours whether they were successful.

So why target a binary asteroid system rather than a single asteroid to see whether you can change its orbit around the sun?

This image of the light from asteroid Didymos and its orbiting moonlet, Dimorphos, is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27. (NASA JPL DART Navigation Team)

“A binary system was perfect for this test,” said Mallory DeCoster, a senior scientist at Johns Hopkins University’s Applied Physics Laboratory in Maryland and part of the DART Impact Modeling Working Group.

For one, the size of Dimorphos — about 164 metres across — is perfect to illustrate whether this would be an effective way of deflecting asteroids that pose a threat to Earth. Didymos is 780 metres across.

“But then the other piece is, if we were to impact a single asteroid, in order to characterize if we changed its orbit, we would have to wait until it completed its orbit around the sun, which could take many, many years.”

The other advantage is that the binary system is relatively close to us, astronomically speaking, at just 11 million kilometres away.

Shooting gallery

NASA’s Center for Near-Earth Object Studies says that more than 90 per cent of near-Earth objects (NEOs) bigger than one kilometre have already been discovered. But that doesn’t mean we’re out of the woods when it comes to Potentially Hazardous Asteroids (PHAs).

In 2013, the Chelyabinsk asteroid — which was roughly 20 metres in diameter— exploded over parts of Russia, injuring about 1,000 people and serving as a reminder of how even a small asteroid can be dangerous.

In February 2013, a meteorite contrail was seen over Chelyabinsk, Russia, a city close to the Ural Mountains located about 1,500 kilometres east of Moscow. The Chelyabinsk asteroid, which was roughly 20 metres in diameter, exploded over parts of Russia, injuring about 1,000 people. (Chelyabinsk.ru, Yekaterina Pustynnikova/The Associated Press)

Basically, Earth flies through a shooting gallery in space. There are small chunks of debris that burn up in our atmosphere as meteors; bigger ones, like Chelyabinsk; and then even bigger ones that can be catastrophic — all left over from the formation of our solar system.

That’s why space agencies like NASA and the European Space Agency have been trying to develop ways to deflect or nudge a PHA so that its orbit changes and poses no threat to Earth.

Mike Daly, a professor at York University’s Lassonde School of Engineering in Toronto and a co-investigator on DART, said one of the most popular concepts is deflecting asteroids before they become a real threat. But that means we need to have advance warning that one is headed our way.

“So the simplest method is the one that DART is doing, which is essentially to take a spacecraft at high speed and crash it into the asteroid and use that transfer of the energy from the spacecraft to the asteroid to move it along,” he said.

This infographic shows the potential effect of DART’s impact on the orbit of Dimorphos. (NASA/Johns Hopkins APL)

However, the science behind asteroid deflection in this manner is about more than just the combination of the spacecraft’s size and incredibly high speed, called a hypervelocity impact.

“In a hypervelocity impact, you induce this pressure wave into the target that causes a lot of new physics to happen,” Johns Hopkins University’s DeCoster said.

“So what will happen, or what we think will happen, is that the size of the spacecraft might actually not matter that much. It might actually be: How does the asteroid respond to this pressure wave that is induced due to the hypervelocity impact? And we think that it will likely spew out a lot of material in the form of ejecta. And this ejecta might actually have a major component for changing the orbit. So much ejecta might get spewed out that that piece might matter more than the incoming energy from the spacecraft in changing its orbit.”

The DART team hopes that an onboard camera, called DRACO, will show the close approach and then suddenly go black, which would be indicative of an impact.

This map shows the 38 telescopic facilities in space and around the globe that are expected to observe the Didymos asteroid system in support of DART’s global observation campaign after impact. Numerical figures in parentheses next to the telescope names indicate the telescope size. (NASA/Johns Hopkins APL/Nancy Chabot/Mike Halstad)

But there’s a straggler tagging along behind DART, by about three minutes: the Italian Space Agency’s Light Italian Cubesat for Imaging of Asteroids, or LICIACube. Its job is to photograph the impact, study the plume of ejecta and help determine the morphology of the asteroid, as they can be made of iron, rock or just rocky clumps held together by gravity.

As this is the first test of a form of planetary defence, scientists are eagerly anticipating not only the impact of the event itself but what they will learn from it and, most importantly, what this may mean for the future of protecting Earth in the future. Telescopes from around the world will be observing the event and collecting followup data.

“We’re really the first generation that can protect ourselves from these potentially catastrophic impacts,” York University’s Daly said. “And, you know, fortunately the really catastrophic ones don’t happen very often, but they could happen, and never before have we been able to change our fate. So I think it’s really up to us, given the potentially large consequences of not paying attention and our ability to do it.”

The event will be broadcast on NASA TV, which is available online and through its app.

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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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