Operating Systems

RISC OS: 35-Year-Old Original ARM OS Is Alive and Well (theregister.com) 51

RISC OS, the operating system of the original Arm computer, the Acorn Archimedes, is still very much alive -- and doing relatively well for its age. The Register reports: In June 1987, Acorn launched the Archimedes A305 and A310, starting at $982 and running a new operating system called Arthur. At the time, it was a radical and very fast computer. In his review (PDF) for Personal Computer World, Dick Pountain memorably said: "It loads huge programs with a faint burping noise, in the time it takes to blink an eye." Arthur was loosely related to Acorn's earlier MOS, the BBC Micro operating system but looked very different thanks to a prototype graphical desktop, implemented in BBC BASIC, that could charitably be called "technicolor." Renamed RISC OS, version 2 followed in 1989 -- the same year that Sun started selling its new SPARCstation 1 (a snip at $9,200) and DEC launched the MIPS R2000-chipset-based DECstation 3100 (for $10,800).

RISC OS has had a rather convoluted history, partly due to Acorn spinning out Arm, eventually pulling out of the computer market, rebranding as Element 14 and being acquired by Broadcom, where Arm co-designer Sophie Wilson still works today. And partly due to drama over the ownership of the OS post-Acorn at one point. One fork of RISC OS still supports Acorn-era Arm's odd 26-bit mode, meaning that today it mostly runs on the commercial Virtual Acorn emulator. The other branch, designed for the 32-bit mode of more recent Arm chips, is now owned by RISC OS Developments, which made it fully open source back in 2018. Development and maintenance is done by the team at RISC OS Open Ltd -- ROOL for short -- which offers downloads for a variety of current Arm hardware, such as the Titanium desktops. [...]

RISC OS Developments are still working on new functionality for the OS. Notably, it recently released a new TCP/IP stack, derived from OpenBSD. Right now, the main benefit is IPv6 support. A feature more significant to most users is still in development: Wi-Fi support. Also still under development, but available to paid backers, is a new RISC OS web browser, Iris. RISC OS does come with a choice of browsers -- NetSurf and Otter -- but the plan is that the new Iris browser will be a native app, with the RISC OS look and feel, but using the WebKit engine for better compatibility with the modern web. The main remaining limitation is SMP. As an OS from the 1980s, long before the 21st-century technology of mainstream multicore processors, RISC OS practically only supports a single CPU core. Various experimental efforts are under way to address this. One has got NetBSD running on another core, and another has the experimental Genode OS running alongside RISC OS. Another effort is working on adding SMP support into the RISC OS kernel itself.

Space

A Chinese Telescope Did Not Find an Alien Signal. The Search Continues. (yahoo.com) 32

Earlier this week China's giant Sky Eye telescope detected signals it thought could be from an alien civilizations.

But now there's an update from LiveScience: Dan Werthimer, a Search For Extraterrestrial Intelligence (SETI) researcher at the University of Berkeley, California and a coauthor on the research project which first spotted the signals, told Live Science that the narrow-band radio signals he and his fellow researchers found "are from [human] radio interference, and not from extraterrestrials....

"The big problem, and the problem in this particular case, is that we're looking for signals from extraterrestrials, but what we find is a zillion signals from terrestrials," Werthimer told Live Science. "They're very weak signals, but the cryogenic receivers on the telescopes are super sensitive and can pick up signals from cell phones, television, radar and satellites — and there are more and more satellites in the sky every day. If you're kind of new in the game, and you don't know all these different ways that interference can get into your data and corrupt it, it's pretty easy to get excited...."

The recent false alarm is one of several instances in which alien-hunting scientists have been misled by noise from human activity. In 2019, astronomers spotted a signal beamed to Earth from Proxima Centauri — the nearest star system to our sun (sitting roughly 4.2 light-years away) and home to at least one potentially habitable planet. The signal was a narrow-band radio wave typically associated with human-made objects, which led scientists to entertain the thrilling possibility that it came from alien technology. Studies released two years later, however, suggested that the signal was most likely produced by malfunctioning human equipment, Live Science previously reported. Similarly, another famous set of signals once supposed to have come from aliens, detected between 2011 and 2014, turned out to have actually been made by scientists microwaving their lunches.

Werthimer tells the New York Times unequivocally that "These signals are from radio interference; they are due to radio pollution from earthlings, not from E.T."

But the Times also got a comment from Paul Horowitz, an emeritus professor of physics at Harvard who created his own alien-listening campaign called Project Meta, funded by the Planetary Society. Those who endure profess not to be discouraged by the Great Silence, as it is called, from out there. They've always been in the search for the long run, they say. "The Great Silence is hardly unexpected," said Dr. Horowitz, including because only a fraction of a percent of the 200 million stars in the Milky Way have been surveyed. Nobody ever said that detecting that rain of alien radio signals would be easy.
Even Dan Werthimer concedes to LiveScience, "I think it'd be very strange if we're the only ones. If you look at the numbers, there's a trillion planets in the galaxy — five times more planets than there are stars. A lot of them are little dinky planets like Earth. Many of them have liquid water, so intelligent life, while not as common as bacterial life, could still be fairly common."
Space

Gaia Probe Reveals Stellar DNA and Unexpected 'Starquakes' (theguardian.com) 29

Astronomers have unveiled the most detailed survey of the Milky Way, revealing thousands of "starquakes" and stellar DNA, and helping to identify the most habitable corners of our home galaxy. From a report: The observations from the European Space Agency's Gaia probe cover almost two billion stars -- about 1% of the total number in the galaxy -- and are allowing astronomers to reconstruct our home galaxy's structure and find out how it has evolved over billions of years. Previous surveys by Gaia, a robotic spacecraft launched in 2013, have pinpointed the motion of the stars in our home galaxy in exquisite detail. By rewinding these movements astronomers can model how our galaxy has morphed over time. The latest observations add details of chemical compositions, stellar temperatures, colours, masses and ages based on spectroscopy, where starlight is split into different wavelengths.

These measurements unexpectedly revealed thousands of starquakes, cataclysmic tsunami-like events on the surface of stars. "Starquakes teach us a lot about stars -- notably, their internal workings," said Conny Aerts of KU Leuven in Belgium, who is a member of the Gaia collaboration. "Gaia is opening a goldmine for asteroseismology of massive stars." Dr George Seabroke, senior research associate at Mullard space science laboratory at University College London, said: "If you can see these stars changing in brightness halfway across the Milky Way, if you were anywhere near them, it would be like the sun changing shape in front of your eyes." Gaia is fitted with a 1bn pixel camera -- the largest ever in space -- complete with more than 100 electronic detectors. The latest dataset represents the largest chemical map of the galaxy to date, cataloguing the composition of six million stars, ten times the number measured in previous ground-based catalogues.

Space

Astronomers May Have Detected a 'Dark' Free-Floating Black Hole (berkeley.edu) 55

"If, as astronomers believe, the death of large stars leave behind black holes, there should be hundreds of millions of them scattered throughout the Milky Way galaxy," notes an announcement from the University of California at Berkeley. "The problem is, isolated black holes are invisible.

"Now, a team led by University of California, Berkeley, astronomers has for the first time discovered what may be a free-floating black hole by observing the brightening of a more distant star as its light was distorted by the object's strong gravitational field — so-called gravitational microlensing." The team, led by graduate student Casey Lam and Jessica Lu, a UC Berkeley associate professor of astronomy, estimates that the mass of the invisible compact object is between 1.6 and 4.4 times that of the sun. Because astronomers think that the leftover remnant of a dead star must be heavier than 2.2 solar masses in order to collapse to a black hole, the UC Berkeley researchers caution that the object could be a neutron star instead of a black hole. Neutron stars are also dense, highly compact objects, but their gravity is balanced by internal neutron pressure, which prevents further collapse to a black hole.

Whether a black hole or a neutron star, the object is the first dark stellar remnant — a stellar "ghost" — discovered wandering through the galaxy unpaired with another star.

"This is the first free-floating black hole or neutron star discovered with gravitational microlensing," Lu said. "With microlensing, we're able to probe these lonely, compact objects and weigh them. I think we have opened a new window onto these dark objects, which can't be seen any other way...." The analysis by Lam, Lu and their international team has been accepted for publication in The Astrophysical Journal Letters. The analysis includes four other microlensing events that the team concluded were not caused by a black hole, though two were likely caused by a white dwarf or a neutron star.

The team also concluded that the likely population of black holes in the galaxy is 200 million — about what most theorists predicted.

Notably, a competing team from the Space Telescope Science Institute (STScI) in Baltimore analyzed the same microlensing event and claims that the mass of the compact object is closer to 7.1 solar masses and indisputably a black hole. A paper describing the analysis by the STScI team, led by Kailash Sahu, has been accepted for publication in The Astrophysical Journal....

The astrometric data came from NASA's Hubble Space Telescope.... While surveys like these discover about 2,000 stars brightened by microlensing each year in the Milky Way galaxy, the addition of astrometric data is what allowed the two teams to determine the mass of the compact object and its distance from Earth.

Earth

Giant Deep Ocean Turbine Trial Offers Hope of Endless Green Power (yahoo.com) 124

"Power-hungry, fossil-fuel dependent Japan has successfully tested a system that could provide a constant, steady form of renewable energy, regardless of the wind or the sun," reports Bloomberg: For more than a decade, Japanese heavy machinery maker IHI Corp. has been developing a subsea turbine that harnesses the energy in deep ocean currents and converts it into a steady and reliable source of electricity.... Called Kairyu, the 330-ton prototype is designed to be anchored to the sea floor at a depth of 30-50 meters (100-160 feet).

In commercial production, the plan is to site the turbines in the Kuroshio Current, one of the world's strongest, which runs along Japan's eastern coast, and transmit the power via seabed cables.... Japan's New Energy and Industrial Technology Development Organization (NEDO) estimates the Kuroshio Current could potentially generate as much as 200 gigawatts — about 60% of Japan's present generating capacity....

Japan is already the world's third largest generator of solar power and is investing heavily in offshore wind, but harnessing ocean currents could provide the reliable baseline power needed to reduce the need for energy storage or fossil fuels.

Thanks to long-time Slashdot reader AmiMoJo for sharing the article!
Space

How NASA's DAVINCI Mission Will Plunge Through Venus's Hellish Atmosphere (gizmodo.com) 69

"NASA's DAVINCI mission to Venus is scheduled for launch in 2029," reports Gizmodo, adding that a new paper "details this upcoming journey, a daring mission that could shed new light on the scorching hot planet's mysterious, and potentially habitable, past." Upon its arrival at the second planet from the Sun, the probe will plunge through Venus' atmosphere, ingesting its gases for approximately one hour before landing on the planet's surface, according to the paper published in The Planetary Science Journal. DAVINCI is designed to act as a flying chemistry lab, and it will use its built-in instruments to analyze Venus's atmosphere, temperatures, pressure and wind speed, while taking a few photos of its trip through planetary hell...

If it survives the atmospheric entry, the probe will — hopefully — land in the Alpha Regio mountains, which are roughly the size of Texas, according to the researchers behind the new paper. Under ideal conditions, the probe will operate for 17 to 18 minutes once it sticks the landing, but it isn't really required to operate on Venus since all the precious data will have already been collected during its atmospheric plunge.

Digital Trends calls Venus "a frontier in planetary science about which very little is known" — then explains why that is. The biggest issue for any potential mission to Venus is the heat, as the surface temperatures can be as high as 900 degrees Fahrenheit (475 degrees Celsius). That's hot enough to melt lead, and it wreaks havoc with electronics... The pressure at the surface is around 95 bars, or nearly 100 times the atmospheric pressure on Earth's surface, so engineering a probe for this kind of environment is kind of like building a submarine... To keep the probe active for as long as possible, it is spherical and covered in a thick titanium shell to withstand the pressure and insulate against the heat. Then there's more insulation inside this shell, made of special materials including astroquartz, a type of fiber made from fused quartz... It's then filled with carbon dioxide gas to protect the high-voltage electronics from sparking and to stop any Earth gases from leaking in during launch....

The descent sphere will also have a camera that will be snapping high-contrast images of the surface, which can then be built up into 3D maps. For a camera to operate from inside a metal sphere, though, you need a window. And glass isn't a great material for dealing with intensely high-pressure environments. That's why DAVINCI's window will be made not of glass but sapphire... "Our final images will have 10-centimeter resolution," said the team's principal investigator, Jim Garvin. "That's the scale you'd see looking out across your living room...."

Researchers know that the clouds of Venus have drops of sulfuric acid in them — and sulfuric acid eats through materials. It's a particular concern for the Kevlar lanyard that will attach the descent sphere to the parachute. So to test whether the lanyard can withstand the acidic environment, the engineers don't just suspend it in a few drops of acid — they coat the entire surface in acid, then test the lanyard's pull strength to make sure it can survive long enough to take the probe through the atmosphere even in the worst possible case.

SciTechDaily notes DAVINCI "is the first mission to study Venus using both spacecraft flybys and a descent probe....

"It will also provide the first descent imaging of the mountainous highlands of Venus while mapping their rock composition and surface relief at scales not possible from orbit."
Space

Remembering the Transit of Venus on Its 10th Anniversary (space.com) 27

"Venus crossed the sun's face 10 years ago today," writes Space.com. "Most people alive will never see the sight again."

Long-time Slashdot reader davidwr is still thinking about it: Slashdot, what are your memories of the 2012 or 2004 transits? What about other celestial events that you probably won't live long enough to see again?
At Space.com, astronomer Tom Kress points out Mercury transits are more common, occurring about 13 times each century — and supplies some context (along with some cool photos): In 1639, English astronomer Jeremiah Horrocks had improved on Kepler's tables using his own observations and aptitude for mathematics. He predicted a transit of Venus in December of that year with just a few weeks' notice, and sure enough it occurred. Kepler had miscalculated, and Horrocks became one of the only people in the world to have seen a transit of Venus....

Only six Venus transits have occurred since: in 1761 (as predicted by Kepler), 1769, 1874, 1882, 2004 and 2012. They come in pairs separated by eight years, but with more than a century between each set. The next transit won't occur until 2117 and, with this in mind, I made every effort to witness the entirety of the last one 10 years ago....

Shortly after noon local time, the black edge of the silhouette of Venus emerged on the face of the sun... A chorus of vocal awe erupted across the crowd of skywatchers, culminating in cheers of excitement as Venus' night-side began its rapid ingress onto the disk of the sun — a process that took just over 15 minutes....

I couldn't help but feel closer to Venus than I really was, standing on a huge terrestrial volcano and looking out at the most volcanic planet in the solar system.

Earth

Fusion Energy: the 35-Country Clean-Energy Effort to "Bottle the Sun' (cnn.com) 218

This week CNN published an article chronicling how 35 countries "have come together to try and master nuclear fusion, a process that occurs naturally in the sun — and all stars — but is painfully difficult to replicate on Earth.

"Fusion promises a virtually limitless form of energy that, unlike fossil fuels, emits zero greenhouse gases and, unlike the nuclear fission power used today, produces no long-life radioactive waste. Mastering it could literally save humanity from climate change, a crisis of our own making." If it is mastered, fusion energy will undoubtedly power much of the world. Just 1 gram of fuel as input can create the equivalent of eight tons of oil in fusion power. That's an astonishing yield of 8 million to 1. Atomic experts rarely like to estimate when fusion energy may be widely available, often joking that, no matter when you ask, it's always 30 years away. But for the first time in history, that may actually be true....

The main challenge is sustaining it. The tokamak in the UK — called the Joint European Torus, or JET — held fusion energy for five seconds, but that's simply the longest that machine will go for. Its magnets were made of copper and were built in the 1970s. Any more than five seconds under such heat would cause them to melt. ITER uses newer magnets that can last much longer, and the project aims to produce a 10-fold return on energy, generating 500 megawatts from an input of 50 megawatts.... The dimensions are mind-blowing. The tokamak will ultimately weigh 23,000 tons. That's the combined weight of three Eiffel towers. It will comprise a million components, further differing into no fewer than 10 million smaller parts.

This powerful behemoth will be surrounded by some of the largest magnets ever created. Their staggering size — some of them have diameters of up to 24 meters — means they are are too large to transport and must be assembled on site in a giant hall.... Even the digital design of this enormous machine sits across 3D computer files that take up more than two terabytes of drive space. That's the same amount of space you could save more than 160 million one-page Word documents on. Behind hundreds of workers putting the ITER project together are around 4,500 companies with 15,000 employees from all over the globe... Now commercial businesses are preparing to generate and sell fusion energy, so optimistic they are that this energy of the future could come online by mid-century.

But as ever with nuclear fusion, as one challenge is overcome another seems to crop up. The limited stocks and price of tritium is one, so ITER is trying to produce its own. On that front, the outlook isn't bad. The blanket within the tokamak will be coated with lithium, and as escaped plasma neutrons reach it, they will react with the lithium to create more tritium fuel... First plasma is now expected in 2025, and the first deuterium-tritium experiments are hoped to take place in 2035, though even those are now under review — delayed, in part, by the pandemic and persistent supply chain issues.

"This article has some nice photography," writes Slashdot reader technology_dude. "It really makes it hit home on the incredible amount of design and planning work that is required."

The article notes that when Stephen Hawking was asked which scientific discovery he'd like to see in his lifetime, Hawking answered, "I would like nuclear fusion to become a practical power source."
Space

Rare Sight For Amateur Astronomers as Five Planets Align (theguardian.com) 24

Amateur astronomers are preparing for a heavenly treat from Friday as the five planets visible to the naked eye line up in order of their distance from the sun across the pre-dawn sky. From a report: For those who can face the early start, and have an unobstructed view of the horizon to the east and south-east, Mercury, Venus, Mars, Jupiter and Saturn, could all be visible before the faintest, Mercury, vanishes in the glare of sunrise. It is not uncommon to see two or three planets close together, but the five that can be spotted with the naked eye have not appeared in order, as viewed from the northern hemisphere, since December 2004.

"This is really cool," said Prof Beth Biller, personal chair of exoplanet characterisation at Edinburgh University's institute for astronomy. "We now know of many other stars hosting multiple planets. This is a rare opportunity to see the same thing closer to home, with all five 'naked eye' planets in our solar system visible at once." The planets of the solar system orbit the sun in a remarkably narrow plane, meaning that when viewed from Earth, they appear to lie close to an imaginary line in the sky called the ecliptic. The five planets will rise above the horizon in the early hours of Friday, though it may be hard to see them all until later in the month.

Earth

Hit Hard by High Energy Costs, Hawaii Looks To the Sun (nytimes.com) 115

Nearly a third of Hawaii's single-family houses have rooftop solar panels -- more than twice the percentage in California -- and officials expect many more homes to add panels and batteries in the coming years. From a report: Even before energy prices surged globally this year, homeowners, elected leaders and energy executives in Hawaii had decided that rooftop solar panels were one of the best ways to meet demand for energy and tame the state's high power costs. Russia's invasion of Ukraine has only strengthened the state's embrace of renewable energy. Electricity rates in Hawaii jumped 34 percent in April from a year earlier because many of its power plants burn oil, about a third of which came from Russia last year.

While Hawaii faces unique challenges, the state's reliance on solar carries lessons for other states and countries looking to fight climate change and bring down energy costs. The state has increased the use of renewable energy in large part by getting electric utilities to accept rooftop solar rather than fight it, as energy companies in California, Florida and other states have been doing. "In Hawaii, we've come to the recognition that rooftop solar is going to be an important part of our grid, has to be part of our grid," said Shelee Kimura, president and chief executive of Hawaiian Electric Company, the state's largest power provider. "Some people think we're crazy. Some people think we're pretty amazing."

Sci-Fi

Famous 'Alien' Wow! Signal May Have Come From Distant, Sunlike Star (space.com) 36

Researchers may have pinpointed the source of a famous supposed alien broadcast discovered nearly a half century ago. Space.com reports: The prominent and still-mysterious Wow! Signal, which briefly blared in a radio telescope the night of Aug. 15, 1977, may have come from a sun-like star located 1,800 light-years away in the constellation Sagittarius. "The Wow! Signal is considered the best SETI (or the search for extraterrestrial intelligence) candidate radio signal that we have picked up with our telescopes," Alberto Caballero, an amateur astronomer, told Live Science. [...] The Wow! Signal most likely came from some kind of natural event and not aliens, Caballero told Live Science, though astronomers have ruled out a few possible origins like a passing comet. Still, Caballero noted that in our infrequent attempts to say hello to E.T., humans have mostly produced one-time broadcasts, such as the Arecibo message sent toward the globular star cluster M13 in 1974. The Wow! Signal may have been something similar, he added.

Knowing that the Big Ear telescope's two receivers were pointing in the direction of the constellation Sagittarius on the night of the Wow! Signal, Caballero decided to search through a catalog of stars from the European Space Agency's Gaia satellite to look for possible candidates. "I found specifically one sun-like star," he said, an object designated 2MASS 19281982-2640123 about 1,800 light-years away that has a temperature, diameter and luminosity almost identical to our own stellar companion. Caballero's findings appeared May 6 in the International Journal of Astrobiology.
"I think this is perfectly worth doing because we want to point our instruments in the direction of things we think are interesting," Rebecca Charbonneau, a historian who studies SETI at the Harvard-Smithsonian Center for Astrophysics and who wasn't involved in the work, told Live Science. "There are billions of stars in the galaxy, and we have to figure out some way to narrow them down," she added.

But she wonders if looking for only sun-like stars is too limiting. "Why not just look at a bunch of stars?" she asked.
Space

Shards of the Planet Mercury May Be Hiding on Earth (nytimes.com) 5

New research explains how meteorites called aubrites may actually be shattered pieces of the planet closest to the sun from the early days of the solar system. From a report: Mercury does not make sense. It is a bizarre hunk of rock with a composition that is unlike its neighboring rocky planets. "It's way too dense," said David Rothery, a planetary scientist at the Open University in England. Most of the planet, the closest to the sun, is taken up by its core. It lacks a thick mantle like Earth has, and no one is quite sure why. One possibility is that the planet used to be much bigger -- perhaps twice its current bulk or more. Billions of years ago, this fledgling proto-Mercury, or super Mercury, could have been hit by a large object, stripping away its outer layers and leaving the remnant we see behind.

While a nice idea, there has never been direct evidence for it. But some researchers think they have found something. In work presented [PDF] at the Lunar and Planetary Science Conference in Houston in March, Camille Cartier, a planetary scientist at the University of Lorraine in France, and colleagues said pieces of this proto-Mercury may be hiding in museums and other meteorite collections. Studying them could unlock the planet's mysteries. "We don't have any samples of Mercury" at the moment, said Dr. Cartier. Gaining such specimens "would be a small revolution" in understanding the natural history of the solar system's smallest planet. According to the Meteoritical Society, nearly 70,000 meteorites have been gathered around the world from places as remote as the Sahara and Antarctica, finding their way into museums and other collections. Most are from asteroids ejected from the belt between Mars and Jupiter, while more than 500 come from the moon. More than 300 are from Mars.

Space

New Calculations of Solar Spectrum Resolve Decade-Long Controversy About the Sun's Chemical Composition (phys.org) 18

Researchers from the University of Gottingen have published new calculations of the physics of the sun's atmosphere that resolve the apparent contradiction between the modern standard model of solar evolution and the "tried-and-true" method called spectral analysis. "The new calculations of the physics of the sun's atmosphere yield updated results for abundances of different chemical elements, which resolve the conflict," reports Phys.Org. "Notably, the sun contains more oxygen, silicon and neon than previously thought. The methods employed also promise considerably more accurate estimates of the chemical compositions of stars in general." From the report: Highly accurate helioseismic measurements gave results about the sun's interior structure that were at odds with the solar standard models. According to helioseismology, the so-called convective region within our sun where matter rises and sinks down again, like water in a boiling pot, was considerably larger than the standard model predicted. The speed of sound waves near the bottom of that region also deviated from the standard model's predictions, as did the overall amount of helium in the sun. To top it off, certain measurements of solar neutrinos -- fleeting elementary particles, hard to detect, reaching us directly from the sun's core regions -- were slightly off compared to experimental data, as well. Astronomers had what they soon came to call a "solar abundances crisis," and in search of a way out, some proposals ranged from the unusual to the downright exotic. Did the sun maybe accrete some metal-poor gas during its planet-forming phase? Is energy being transported by the notoriously non-interacting dark matter particles?

The newly published study by Ekaterina Magg, Maria Bergemann and colleagues has managed to resolve that crisis, by revisiting the models on which the spectral estimates of the sun's chemical composition are based. [...] In this study they tracked all chemical elements that are relevant to the current models of how stars evolved over time, and applied multiple independent methods to describe the interactions between the sun's atoms and its radiation field in order to make sure their results were consistent. For describing the convective regions of our sun, they used existing simulations that take into account both the motion of the plasma and the physics of radiation ("STAGGER" and "CO5BOLD"). For the comparison with spectral measurements, they chose the data set with the highest available quality: the solar spectrum published by the Institute for Astro- and Geophysics, University of GÃttingen. "We also extensively focused on the analysis of statistical and systematic effects that could limit the accuracy of out results," notes Magg. The new calculations showed that the relationship between the abundances of these crucial chemical elements and the strength of the corresponding spectral lines was significantly different from what previous authors had claimed. Consequently, the chemical abundances that follow from the observed solar spectrum are somewhat different than stated in previous analysis.

"We found, that according to our analysis the sun contains 26% more elements heavier than helium than previous studies had deduced," explains Magg. In astronomy, such elements heavier than helium are called "metals." Only on the order of a thousandth of a percent of all atomic nuclei in the sun are metals; it is this very small number that has now changed by 26% of its previous value. Magg adds: "The value for the oxygen abundance was almost 15% higher than in previous studies." The new values are, however, in good agreement with the chemical composition of primitive meteorites ("CI chondrites") that are thought to represent the chemical make-up of the very early solar system. When those new values are used as the input for current models of solar structure and evolution, the puzzling discrepancy between the results of those models and helioseismic measurements disappears.

Mars

After 28 Flights, Is NASA's 'Ingenuity' Mars Helicopter Nearing the End of Its Life? (msn.com) 61

After traveling 300 miles on the underbelly of the Perseverance rover, the "Ingenuity" helicopter has made 28 different flights over the surface of Mars, reports the Washington Post, staying aloft for a total of nearly one hour, flying 4.3 miles with a maximum speed of 12.3 miles per hour and a top altitude of 39 feet. "It's traversed craters, taken photos of regions that would be hard to reach on the ground, and served as a surprisingly resilient scout that has adapted to the changing Martian atmosphere and survived its harsh dust storms and frigid nights.

"Now the engineers and scientists at NASA's Jet Propulsion Laboratory are worried that their four-pound, solar-powered drone on Mars, may be nearing the end of its life." Winter is setting in on Mars. The dust is kicking up, coating Ingenuity's solar panels and preventing it from fully charging its six lithium-ion batteries. This month, for the first time since it landed on Mars more than a year ago, Ingenuity missed a planned communications session with Perseverance, the Mars rover that it relies on to send data and receive commands from Earth. Will a dust-coated Ingenuity survive a Martian winter where temperatures routinely plunge below minus-100 degrees Fahrenheit? And if it doesn't, how should the world remember the little helicopter that cost $80 million to develop and more than five years to design and build? Those closest to the project say that as time winds down for Ingenuity, it's hard to overstate its achievements....

"We built it as an experiment," Lori Glaze, the director of NASA's planetary science division, told The Washington Post. "So it didn't necessarily have the flight-qualified parts that we use on the big missions like Perseverance." Some, such as components from smartphones, were even bought off-the-shelf, so "there were chances that they might not perform in the environment as we expected. And so there was a risk that it wasn't going to work.... What happened was, and this is really key, after Ingenuity performed so well on those first five flights, the science team from Perseverance came to us and said, 'You know what, we want this helicopter to keep operating to help us in our exploration and achieving our science goals,' " Glaze said.

So NASA decided to keep flying....

On April 29, it took its last flight to date, No. 28, a quarter-of-a-mile jaunt that lasted two-and-a-half minutes. Now NASA wonders if that will be the last one. The space agency thinks the helicopter's inability to fully charge its batteries caused the helicopter to enter a low-power state. When it went dormant, the helicopter's onboard clock reset, the way household clocks do after a power outage. So the next day, as the sun rose and began to charge the batteries, the helicopter was out of sync with the rover: "Essentially, when Ingenuity thought it was time to contact Perseverance, the rover's base station wasn't listening," NASA wrote.

Then NASA did something extraordinary: Mission controllers commanded Perseverance to spend almost all of May 5 listening for the helicopter.

Finally, little Ingenuity phoned home.

The radio link, NASA said, "was stable," the helicopter was healthy, and the battery was charging at 41 percent.

But, as NASA warned, "one radio communications session does not mean Ingenuity is out of the woods. The increased (light-reducing) dust in the air means charging the helicopter's batteries to a level that would allow important components (like the clock and heaters) to remain energized through the night presents a significant challenge."

Maybe Ingenuity will fly again. Maybe not.

"At this point, I can't tell you what's going to happen next," Glaze said. "We're still working on trying to find a way to fly it again. But Perseverance is the primary mission, so that we need to start setting our expectations appropriately."

For Ingenuity's "Wright Brothers moment" — when it flew for the first time on another planet — it was actually carrying a postage-sized bit of fabric from the Wright Brothers original 1903 aircraft.
Space

The Milky Way's Black Hole Comes to Light (nytimes.com) 65

Astronomers announced today that they had pierced the veil of darkness and dust at the center of our Milky Way galaxy to capture the first picture of "the gentle giant" dwelling there: A supermassive black hole, a trapdoor in space-time through which the equivalent of 4 million suns have been dispatched to eternity, leaving behind only their gravity and a violently bent space-time. From a report: The image, released in six simultaneous news conferences in Washington, D.C., and around the globe, showed a lumpy doughnut of radio emission framing an empty space as dark and silent as death itself. The new image joins the first ever picture of a black hole, produced in 2019 by the same team, which photographed the monster at the heart of the M87. The new image shows new details of the astrophysical violence and gravitational weirdness holding sway at the center of our placid-looking hive of starlight.

Black holes were an unwelcome consequence of Albert Einstein's general theory of relativity, which attributes gravity to the warping of space and time by matter and energy, much as a mattress sags under a sleeper. Einstein's insight led to a new conception of the cosmos, in which space-time could quiver, bend, rip, expand, swirl and even disappear forever into the maw of a black hole, an entity with gravity so strong that not even light could escape it. Einstein disapproved of this idea, but the universe is now known to be speckled with black holes. Many are the remains of dead stars that collapsed inward on themselves and just kept going. But there seems to be a black hole at the center of nearly every galaxy, ours included, that can be millions or billions of times as massive than our sun. Astronomers still do not understand how these supermassive black holes have grown so big.

Moon

NASA Is Sending Artificial Female Bodies To the Moon To Study Radiation Risks (gizmodo.com) 66

An anonymous reader quotes a report from Gizmodo: Helga and Zohar are headed for a trip around the Moon on an important mission, measuring radiation risks for female astronauts for the first time. The inanimate pair are manikins modeled after the body of an adult woman. For the Artemis 1 mission, in which an uncrewed Orion capsule will travel to the Moon and back, one of the manikins will be outfitted with a newly developed radiation protection vest. Helga and Zohar, as they're called, won't be alone, as they'll be joined by a third manikin that will collect data about flight accelerations and vibrations. Artemis 1 is scheduled to blast off later this year. The Artemis program aims to return humans to the Moon for the first time in over 50 years, but this time the space agency has vowed to land the first woman on the dusty lunar surface. [...]

The Helga and Zohar manikins are part of the MARE experiment, designed by the German Aerospace Center (DLR). The experiment will use two identical representations of the female body to investigate radiation exposure throughout the flight of the Artemis 1 mission, which may last up to six weeks. Artemis 1 will set the stage for Artemis 2, in which an Orion capsule carrying real humans will fly to the Moon and back (without landing), possibly as early as 2024. [...] Here's how it will work. The manikins are made from materials that mimic the bones, soft tissues, and organs of an adult woman, all of which will be tracked by more than 10,000 passive sensors and 34 active radiation detectors, according to DLR. One of the manikins, Helga, will fly to the Moon unprotected while the other one, Zohar, will wear a radiation protection vest called the AstroRad (which was developed by American aerospace company Lockheed Martin and Israeli startup StemRad).

As they travel aboard the Orion spacecraft to the Moon, Helga and Zohar will be affected by the harsh environment of space. The manikins, having traveled beyond the protective shielding of Earth's magnetosphere, will be exposed to various types of space radiation, like charged particles produced by the Sun or energy particles trapped within Earth's atmosphere. Space radiation is known to alter molecules of DNA, which is obviously not good for human health. Upon their arrival back at Earth, data collected from the two manikins will help researchers to better understand the level of protection provided by the newly developed AstroRad vest.

United States

Pilots Contend With Record Number of Laser Strikes, FAA Says (nytimes.com) 97

Several readers have shared this report: One foggy night in December 2018, David Hill was trying to land a helicopter when a beam of light suddenly overwhelmed his night vision goggles. Mr. Hill, an emergency services pilot, had been called to airlift a teenager who had been badly injured in an all-terrain vehicle crash from a village 35 miles north of Madison, Wis. But now, Mr. Hill was temporarily blinded. Flying about 500 feet above the ground, he tried to get his bearings. It was "like looking into the sun, and all I can see are bright spots," he recalled. A person had pointed a laser at his helicopter. From 2010 to 2021, close to 70,000 pilots reported similar episodes, according to the Federal Aviation Administration. Last year it recorded more than 9,700 cases, a record high, and a 41 percent increase from 2020. When a laser pointer reaches a cockpit, the light can disorient or "completely incapacitate" a pilot, who on a commercial airplane could be responsible for hundreds of passengers, the F.A.A. said. Some commercial flight paths have been disrupted, causing pilots to change course or even turn around. "What you might see as a toy has the capacity to momentarily blind the crew member," Billy Nolen, the acting administrator of the F.A.A., said. Though no plane has ever been reported to have crashed as a result of a laser strike, Mr. Nolen said in a phone interview that there was always a risk of a "tragic outcome." He added, "This is not an arcade game."
Idle

50 Years Later: a Rebirth for Polaroid's 'Instant Cameras'? (fastcompany.com) 46

In 1972, photo prints that developed before your eyes were "downright magical," argues Fast Company — "and still meaningful today."

A new article at Fast Company points out that while Polaroid went bankrupt twice, and stopped making cameras in 2007, "Then an unexpected thing happened: It turned out that even Polaroid couldn't kill Polaroid." Even as instant photography's eulogies were being written, a band of enthusiasts known as The Impossible Project bought the last Polaroid factory that hadn't been hastily dismantled and started producing film packs again. The task required reformulating its own chemistry from scratch, and it was years until the results reached the vicinity of original Polaroid quality. Fans were very patient.

Eventually, the Impossible Project and Polaroid came under the same ownership, adopted Polaroid as the unified brand, and started making instant cameras again. The new models start at $100 and look a lot like that 1977 OneStep, even when they're adorably miniaturized. It's almost as if Polaroid's years in limbo were a bad dream.... Polaroid and several smaller companies refurbish old models, replacing worn parts and otherwise returning them to optimum performance. Repairing an SX-70 generally involves permanently removing its leather, but replacement skins are available in an array of styles, from the traditional to the psychedelic.

Increasingly, yesteryear's Polaroid cameras are springing back to life in surprising ways. Wisconsin-based Retrospekt not only revives old models, but also encases antique innards in new plastic shells, allowing it to sell branding crossovers such as Malibu Barbie and Pepsi-themed Polaroid cameras. Hong Kong's Mint offers a camera called the SLR670 that's really a restored SX-70 accompanied by a gizmo that plugs into the flash port to allow for manual settings. And Open SX-70 is a project to smarten up the SX-70 by replacing its 1970s circuit board with a tiny Arduino computer.

Other things I learned from the article:
  • "Each film pack contained its own battery, so the camera would never run out of juice at an inopportune moment."
  • Kodak was forced out of the instant photography market in 1986 by a Polaroid patent infringement suit in which Polaroid won $925 million in damages.
  • Edwin Land's "final gambit to revolutionize photography" was 1977's wildly unpopular Polavision instant home movies.
  • There's a 1974 ad for the cameras narrated by Laurence Olivier.

Power

California Ran On Nearly 100% Clean Energy This Month (bloombergquint.com) 202

An anonymous reader quotes a report from Bloomberg: California, which aims to have a carbon-free power grid within 25 years, got a short glimpse of that possibility earlier this month. The state's main grid ran on more than 97% renewable energy at 3:39 p.m. on Sunday April 3, breaking a previous record of 96.4% that was set just a week earlier, the California Independent System Operator said Thursday in a statement. While these all-time highs are for a brief time, they solidly demonstrate the advances being made to reliably achieve California's clean energy goals," said California ISO CEO Elliot Mainzer said in the statement.

Power production from the sun and wind typically peak in the spring, due to mild temperatures and the angle of the sun allowing for an extended period of strong solar production, the grid operator said. While hitting the new renewable record is remarkable, the state has found itself scrambling for power supplies during the past two summers as it has added more intermittent sources and retired natural-gas plants for environmental reasons. California has set a target to have a zero-carbon power system by 2045.

NASA

Hubble Telescope Confirms Largest Comet Nuclear Ever Seen (npr.org) 33

NASA's Hubble Space Telescope has confirmed the largest icy comet nucleus ever seen by scientists. NPR reports: The nucleus of comet C/2014 UN271 (Bernardinelli-Bernstein) is about 80 miles in diameter, which is larger than the state of Rhode Island, NASA says. The comet's nucleus is about 50 times larger than that of most comets, and its mass is estimated to be a gigantic 500 trillion tons.

Comet C/2014 UN271 was discovered by astronomers Pedro Bernardinelli and Gary Bernstein using archival images from the Cerro Tololo Inter-American Observatory in Chile. The comet has been observed since 2010, when it was 3 billion miles away from the sun, and has been studied since then. NASA says there was a challenge in measuring the comet's nucleus because it was too far away for the Hubble telescope to determine its size. Instead, scientists had to make a computer model that was adjusted to fit the images of the comet's bright light that they got from the telescope's data.

Despite traveling at 22,000 mph, the massive comet is still coming from the edge of the solar system. But NASA assures us that it will never get closer than 1 billion miles away from the sun -- and even then, that won't be until 2031. The previous record-holder for largest comet nucleus was discovered in 2002. Comet C/2002 VQ94 was approximately 60 miles across.

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