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Ryugu’s rubble suggests its short life has been rather turbulent

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Sept. 21 (UPI) — The asteroid Ryugu is a loose assemblage of fragments from a collision between two asteroids, according to new research published Monday in the journal Nature Astronomy.

Some asteroids are composed of large, solid pieces of rock, but Ryugu is more like a rubble pile than a rock. It is too small and fragile to have remained intact for very long — scientists estimate Ryugu formed between 10 million to 20 million years ago.

“Ryugu is too small to have survived the whole 4.6 billion years of solar system history,” Seiji Sugita, professor of planetary sciences at the University of Tokyo in Japan, said in a news release. “Ryugu-sized objects would be disrupted by other asteroids within several hundred million years on average.”

“We think Ryugu spent most of its life as part of a larger, more solid parent body,” Sugita said. “This is based on observations by Hayabusa-2 which show Ryugu is very loose and porous. Such bodies are likely formed from reaccumulations of collision debris.”

For the latest study, scientists used images collected by Hayabusa-2 to identify the different types of rock on Ryugu. Researchers were able to uncover clues to the asteroid’s violent past by analyzing the ratios of different rock types.

“Ryugu is considered a C-type, or carbonaceous, asteroid, meaning it’s primarily composed of rock that contains a lot of carbon and water,” said postdoctoral researcher Eri Tatsumi. “As expected, most of the surface boulders are also C-type; however, there are a large number of S-type, or siliceous, rocks as well. These are silicate-rich, lack water-rich minerals and are more often found in the inner, rather than outer, solar system.”

The presence of siliceous rocks suggests Ryugu was formed from the rubble created by a collision between between a small S-type asteroid and a larger C-type asteroid.

“We used the optical navigation camera on Hayabusa2 to observe Ryugu’s surface in different wavelengths of light, and this is how we discovered the variation in rock types. Among the bright boulders, C and S types have different albedos, or reflective properties,” said Tatsumi.

Once Hayabusa-2 returns rock samples to Earth, scientists plan to compare the asteroids geochemical composition to meteorites samples found on Earth.

“This could in turn tell us something new about the history of Earth and the solar system as a whole,” Tatsumi said.



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SpaceX launches 60 more Starlink broadband satellites

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Oct. 18 (UPI) — SpaceX launched its 14th group of 60 satellites from Florida under blue skies Sunday for the company’s Starlink broadband network, which is approaching a full-scale public trial period.

Liftoff occurred on time at 8:25 a.m. EDT aboard a Falcon 9 rocket from Complex 39A at Kennedy Space Center.

The launch boosted the number of satellites in orbit to nearly 800.

After the previous Starlink launch Oct. 6, SpaceX founder and CEO Elon Musk tweeted that the launch would soon allow it to “roll out a fairly wide public” test in the northern United States and “hopefully” in southern Canada.

“Other countries to follow as soon as we receive regulatory approval,” Musk wrote.

The company said emergency responders in northern Washington State had used the Starlink service in wildfire-stricken areas.

“The way emergency responders deployed Starlink in this context is representative of how Starlink works best-in remote or rural areas where internet connectivity is unavailable,” the company reported on its website. “Our Starlink network is still in its early stages, but as our network grows our coverage will grow as well.”

Another initial user of Starlink is the Hoh tribe of Washington, where the service recently allowed it to offer more online education and telehealth services, according to a video produced by the state officials and posted on YouTube on Oct 7.

“It’s like out of nowhere, SpaceX came up and just catapulted us into the 21st century,” Melvinjohn Ashue, vice chairman of the tribe, said in the video.

SpaceX also won the right from the Federal Communication Commission last week to bid for $16 billion in federal funding to provide broadband service to rural areas of the United States.

The company was listed among 186 qualified bidders for the auction, which also includes such big names as Hughes, CenturyLink, Verizon and ViaSat. The money be released annually over a period of 10 years to internet providers so they can offer lower rates in rural areas.

Musk also confirmed on Twitter that Starlink is intended to be usable on fast-moving cars and trains, as long as the dish receivers are mounted and have a clear view of the sky.

Starlink’s ground receivers are designed to have the ability to move and track Starlink signals automatically.



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Unusual Aussie spider builds one-of-a-kind nest with super strong silk

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Oct. 19 (UPI) — As far scientists know, no other spider builds a nest quite like the Australian basket-web spider.

Thanks to a new study, published Monday in the journal Scientific Reports, scientists now know how the spider’s lobster pot-like web keeps its structure without the help of vegetation.

“This silk retains its rigidity, allowing a rather exquisite silken basket or deadly ant trap,” study co-author Mark Elgar, a professor of evolutionary biology at the University of Melbourne, said in a news release.

For the study, researchers closely examined the chemical and structural composition of the spider’s silk. Their analysis showed the silk is similar to the kind of silks used by other spiders to construct egg sacs.

“Our discovery may provide insights into the evolution of foraging webs,” said Elgar. “It is widely thought that silk foraging webs, including the magnificent orb-webs, evolved from the habit of producing silk to protect egg cases. Perhaps the basket-web is an extension of the protective egg case and represents a rare contemporary example of an evolutionary ancestral process.”

The lobster pot trap of the basket-web spider, found only in Australia, measures just less than a half-inch in diameter and a bit more than a half-inch in length. It features a series of cross-linked threads of varying diameters.

Researchers were able to analyze the web and its robust fibers using high-resolution imaging technologies at ANSTO’s Australian Synchrotron facilities.

“Nature has created a complex structure that, at first glance, resembles industrially produced composites,” said study co-author Thomas Scheibel, professor of biomaterials at the University of Bayreuth in Germany.

“Further investigations have, however, shown that they are chemically different components and their respective properties together result in the thread’s extreme elasticity and toughness, thus creating a high degree of robustness,” Scheibel said. “With today’s composite materials, on the other hand, it is mainly the fibers embedded in the matrix that establish the particular properties required, such as high stability.”

The research suggests a new genetic material is key to the robustness of the novel silk — a material that could be synthesized at scale for industrial applications.

Scientists estimate, however, that additional research is needed to isolate the material and realize its potential.

“There is increasing recognition that solutions to many of the complex challenges and puzzles we face today can be found from biological systems,” Elgar said.

“This so-called ‘Bioinspiration’ draws on some 3.8 billion years of natural selection honing biological forms, processes and systems. The potential insights from that diversity of life, about which we still know rather little, is staggering,” Elgar said.



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‘Happy ending effect’ impairs future decision-making, study says

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Oct. 19 (UPI) — Humans rely on their experiences to inform their decision making process, but new research suggests the “happy ending effect” prevents humans from accurately gauging the true value of an experience.

Previous studies have shown that humans overemphasize the ending of an experience when assessing its value. For example, a spell of bad weather on the last couple days of a vacation can leave travelers with a feeling of disappointment, spoiling their impression of the otherwise enjoyable trip.

New research, published Monday in the Journal of Neuroscience, suggests the phenomenon can interfere with a person’s ability to make good decisions.

“When you’re deciding where to go for dinner, for example, you think about where you’ve had a good meal in the past,” lead study author Martin Vestergaard said in a news release.

“But your memory of whether that meal was good isn’t always reliable — our brain values the final few moments of the experience more highly than the rest of it. If we can’t control our in-built attraction to happy endings, then we can’t trust our choices to serve our best interests,” said Vestergaard, a neuroscientist at the University of Cambridge in Britain.

For the study, researchers had participants select between two streams of coins falling into a bucket in quick succession. Larger coins were higher in value.

One stream was greater in value but ended with a succession of smaller coins, while the other less-valuable stream ended with a run of bigger coins. Participants consistently — and incorrectly — selected the stream that ended with larger coins.

Researchers used brain activity recordings and computational models to better understand the phenomenon. The analysis confirmed that the experience valuation process was encoded in the amygdala.

The study’s authors suggest it’s important for the human brain to observe the upward or downward trajectory of an experience — but the process can also impair a person’s ability to accurately evaluate an overall experience.

“Our attraction to the quality of the final moment of an experience is exploited by politicians seeking re-election; they will always try to appear strong and successful toward the end of their time in office,” said Vestergaard. “If you fall for this trick, and disregard historical incompetence and failure, then you might end up re-electing an unfit politician.

“Sometimes it’s worth taking the time to stop and think,” he said. “Taking a more analytical approach to complement your intuitive judgement can help ensure you’re making a rational decision.”



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