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Look: Stardust embedded in ancient meteorite tells the origin story of the Sun – Inverse

On Sunday morning, September 28, 1969, an ancient visitor came crashing down on Earth.

A 4.6 billion-year-old meteorite landed in a small farming town north of Melbourne, Australia, and inside, it contained ancient secrets of the universe. More than 50 years later, the solid slab of cosmic material keeps on giving.

A team of researchers analyzed grains of ancient stardust found in the rock — dubbed the Murchison meteorite — linking them to ancient carbon stars that formed far before the Solar System but are considered the building blocks of stars like our Sun.

The researchers detail their findings in a study published in The Astrophysical Journal Letters.

Here’s the background — Nan Liu, research assistant professor of physics in Arts & Sciences at Washington University in St. Louis, and lead author of the study, explains how ancient stardust can get us familiar with our own star system.

“Our Solar System was made from this stardust and the gas expelled from their parent stars,” Liu tells Inverse. “So by studying these types of grains, we know what type of stars contributed material to our Solar System … and these grains help us understand whether our Solar System is unique or common in the whole galaxy.”

An electron microscope image of a micron-sized silicon carbide, SiC, stardust grain (lower right) ex...

The grains from ancient stars are often found in meteorites that end up on Earth.NASA, Nan Liu and Andrew Davis

What’s new — Embedded deep within samples from the Murchison meteorite are grains of stardust from carbon-rich stars that are over 4.6 billion years old. The grains formed in the cooling winds swept off the surface of low-mass, carbon-rich stars near the end of their lives.

“For stars that do not experience explosions, low-mass stars, they experience strong mass loss near the end of their lives from the surface due to stellar winds, and the lost stellar gas gradually cools for dust grains to condense,” Liu says. “For stars that explode at the end of their lives in supernovae, first you have a supernova remnant consisting of hot ionized gas, and then the remnant slowly cools down to form dust grains.”

The grains found in the meteorite came from ancient stars, ones that are up to three times more massive than the Sun.

Our Sun primarily consists of hydrogen and helium, but these larger stars have higher temperatures, burning helium to make carbon. That is why these pre-solar dust grains have higher carbon concentrations than would be found in a star like the Sun.

The data from the new study will help scientists create better models of ancient stars and how they evolved over time to become stars like our Sun.

Abstract: We report NanoSIMS Si and Mg–Al isotopic data (and C, N, and Ti isotopic data, when available) for 85 submicron- to micron-sized presolar SiC grains from the CM2 Murchison meteorite, including 60 mainstream (MS), 8 AB1, 8 X, 7 AB2, and 2 Y grains. The MS and Y grain data demonstrate that (1) C and N contamination mainly appears as surface contamination, and sufficient presputtering is needed to expose a clean grain surface for obtaining intrinsic C and N signals, and (2) Mg and Al contamination appears as adjacent grains and rims, and high-resolution imaging and the choice of small regions of interest during data reduction together are effective in suppressing the contamination. Our results strongly indicate that previous studies of presolar SiC grains could have sampled differing degrees of contamination for C, N, Mg, and Al. Compared to the literature data, our new MS and Y grains are in better agreement with carbon star observations for both the C and N isotopic ratios. By comparing our new, tighter distributions of 12C/13C, 14N/15N, and initial 26Al/27Al ratios for MS and Y grains with FRUITY low-mass asymptotic giant branch (AGB) stellar models, we provide more stringent constraints on the occurrence of cool bottom processing and the production of 26Al in N-type carbon stars, which are classical AGB stars.

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Manchester Airport evacuated: Police close off terminal as security scare grounds flights – Express

Passengers and staff were told to leave Terminal Two of the airport following a security scare this afternoon. Greater Manchester Police confirmed it was called to the scene shortly after 3pm.

A police cordon has been place in surrounding areas while an investigation takes place.

Pictures from the scene show several police vehicles blocking the entrance to the drop-off point at Terminal Two.

Some flights are currently being diverted to Terminal One, according to reports.

Other passengers at the terminal are understood to kept waiting at the departure gates.

One passenger has reported being stuck inside the airport for more than an hour.

Mathew Spencer tweeted: “Stuck in Terminal 2 now for over an hour with hundreds of people and no information.

“Staff are clueless and refuse to escalate questions, saying it is ‘just’ a serious security matter. @manairport please communicate with us and tell us why we are stuck here.”

In a statement, the force said: “Police were called with a report of a suspicious package in Terminal 2 of Manchester Airport at around 3.20pm today (19 October 2021).

“The terminal has been evacuated as per standard procedure and a cordon has been put in place as a safety precaution while an assessment is carried out.”

A spokesperson for Manchester Airport said: “Following a report of a suspicious package in Terminal Two, a controlled evacuation is taking place as per standard procedure.

“We are in close contact with Greater Manchester Police, who are managing the response, and will provide an update on the situation as soon as possible.”

Terminal Two of Manchester Airport completed its billion pound upgrade in July.

The project planned in 2015 was scheduled to be finished in 2020 but was delayed due to the coronavirus pandemic.

Terminal Two is now equipped with 10 security lanes, which stretch 29-metres long, and features the latest technology to speed up arrivals and departures.

It also has two airport lounges with a capacity of 400 on the upper floor to give waiting passengers a panoramic view of the airfield.

Karen Smart, Managing Director of Manchester Airport, said: “It is a proud milestone for our airport as we begin to emerge from the restrictions brought about by the COVID-19 crisis, and an important moment in our 83-year history.

“This project was always about offering the modern airport experience that families and businesses across the North deserve as they travel through their international gateway to the world, and our new terminal certainly delivers on that goal.”

Passengers are advised to check departure screens for more information.

Flights to destinations, including Amsterdam, Zurich and Dublin are thought to be affected.

This is a developing news story, more to follow.

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Bullet Rips Through Nelson Chamisa's Vehicle in Orgy of Violence in Zimbabwe's Manicaland Province – VOA Zimbabwe

Zimbabwe’s opposition MDC Alliance claims that a bullet hit Nelson Chamisa’s vehicle in Manicaland province today where he was expected to hold meetings with traditional leaders and locals as part of his nationwide meet the people tour.

In a series of tweets, the party said, “A bullet flew through one window of the vehicle carrying President Nelson Chamisa & out through the other. This attempted assassination & use of gunshots on President Chamisa’s vehicle & another that is part of his convoy are cause for grave concern.

“There has been another attempted assassination on President Nelson Chamisa. Armed thugs threw large boulders at his vehicle which has been badly damaged. The President’s vehicle sped off & continues to be trailed by more than 12 unmarked cars.”

Party spokesperson, Fadzayi Mahere, also in a tweet, said, “Violence of the sort experienced in Masvingo has broken out in Mutare where President @nelsonchamisa is set to meet community leaders.”

Mahare claimed that a number of vehicles carrying armed, rowdy thugs were trailing Chamisa’s convoy.

According to the MDC Alliance, party activists accompanying Chamisa, have reported that the Mutare Road has been barricaded with stones and “thugs carrying knives and knobkerries” are causing havoc. Some of them are reportedly armed.

A video posted by the MDC Alliance on its social media platforms shows a vehicle with what looks like two bullet holes in Chamisa’s vehicle.

The party is in the process of reporting the violent attack of MDC Alliance actisits to the police in Manicaland.

Police spokesperson Senior Assistant Commissioner Paul Nyathi was unreachable for comment as he was not responding to calls on his mobile phone.

Zanu PF officials were unreachable for comment. Last week, senior party member Patrick Chinamasa aknowledged that Zanu PF supporters blocked Chamisa from attending meetings in Masvingo.

Chinamasa said the villagers in Chief Charumbira area did not want to be addressed by the opposition leader.

Suspected Zanu PF supporters waiving anti-sanctions placards stoned Chamisa’s advance party in Masvingo last week.

No person has been arrested in connection with the incident.

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Humans Are Actually Terrible at Navigating Cities, Study of Over 14,000 People Shows – ScienceAlert

We design cities. We live in them. We work in them, and we have fun in them. But boy howdy are we bad at getting around them.

According to mobile phone data from over 14,000 people living their daily lives, humans are terrible at calculating the shortest route through city streets. And the reason is really simple: our brains want us to face the direction we are going in, even if that’s not the most efficient way of getting to our destination.

An international team of researchers led by MIT have now called this the ‘pointiest path’, and believe it occurs because our brains prioritize other tasks at the cost of navigational efficiency.

“There appears to be a trade-off that allows computational power in our brain to be used for other things – 30,000 years ago, to avoid a lion, or now, to avoid a perilous SUV,” says architect and engineer Carlo Ratti of MIT’s Senseable City Laboratory.

“Vector-based navigation does not produce the shortest path, but it’s close enough to the shortest path, and it’s very simple to compute it.”

The seeds of the study were planted two decades ago, when Ratti was a student at the University of Cambridge in the UK. He noticed that he traveled to his department building along one route, but took a different route to get back to his room. It stands to reason that one route is shorter than the other, but the pattern of behavior held.

Since that time, technology has changed – and now we have the tools for collecting huge amounts of data on our activities. Large numbers of humans in many cities now keep a small, powerful computer on their person that can track their movements, an absolute treasure trove for scientists wanting to know why we choose the paths we do.

This is what the researchers tapped into: Completely anonymized data from over 14,000 pedestrians, whose GPS coordinates were recorded as they moved around the cities of Boston and Cambridge, Massachusetts and San Francisco, California over the course of a year. This included over 550,000 paths – enough data to discern some patterns.

Sure enough, a fascinating pattern did emerge. Rather than choosing the shortest path, pedestrians overwhelmingly chose to travel the path that allowed them to more directly face towards their destination as much as possible – even if turning aside would have taken them there more quickly.

Then, the researchers went a step further, generating a model to predict the irrational paths that appeared in the data. This confirmed that people do indeed prefer to face towards their destination.

“Instead of calculating minimal distances, we found that the most predictive model was not one that found the shortest path, but instead one that tried to minimize angular displacement – pointing directly toward the destination as much as possible, even if traveling at larger angles would actually be more efficient,” said computer scientist Paolo Santi of MIT and the Italian National Research Council in Italy.

“We have proposed to call this the pointiest path.”

Moreover, when making a round trip, people tended to choose different routes for the journey to the destination, and the journey back again, just like Ratti had caught himself doing at the University of Cambridge.

The pointiest path hasn’t only been observed in humans. It’s been recorded in animals, too, described as vector-based navigation. These studies suggest the brain navigates by calculating vectors; since most of us don’t have top-down maps in our brains to navigate the way GPS does, vector-based navigation seems to be the next best strategy.

This is because evolution doesn’t seek optimization, but “sure, OK, that works, I’m not dead” – something that has been dubbed “survival of the adequate“.

The study results could help us design better cities, but they also underscore the need to understand the different ways brains and machines work.

“Computers are perfectly rational. They do exactly what code tells them to do. Brains, on the other hand, achieve a ‘bounded rationality’ of ‘good enoughs’ and necessary compromises. As these two distinct entities become increasingly entangled and collide – on Google Maps, Facebook or a self-driving car – it’s important to remember how they are different from each other,” Ratti wrote for The Conversation.

“The more people become wedded to technology, the more important it becomes to make technologies that accommodate human irrationalities and idiosyncrasies.”

The research has been published in Nature Computational Science.

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