Communications

Einstein's Theory of Relativity, Critical For GPS, Seen In Distant Stars (phys.org) 48

Using NASA's Chandra X-ray Observatory, astronomers have discovered that "gravitational redshift" exists in two stars orbiting each other in our galaxy about 29,000 light years (200,000 trillion miles) away from Earth. Gravitational redshifts, where light is shifted to redder colors because of gravity, "have tangible impacts on modern life, as scientists and engineers must take them into account to enable accurate positions for GPS," reports Phys.Org. From the report: The intriguing system known as 4U 1916-053 contains two stars in a remarkably close orbit. One is the core of a star that has had its outer layers stripped away, leaving a star that is much denser than the Sun. The other is a neutron star, an even denser object created when a massive star collapses in a supernova explosion. The neutron star (grey) is shown in this artist's impression at the center of a disk of hot gas pulled away from its companion (white star on left). These two compact stars are only about 215,000 miles apart, roughly the distance between the Earth and the Moon. While the Moon orbits our planet once a month, the dense companion star in 4U 1916-053 whips around the neutron star and completes a full orbit in only 50 minutes.

In the new work on 4U 1916-053, the team analyzed X-ray spectra -- that is, the amounts of X-rays at different wavelengths -- from Chandra. They found the characteristic signature of the absorption of X-ray light by iron and silicon in the spectra. In three separate observations with Chandra, the data show a sharp drop in the detected amount of X-rays close to the wavelengths where the iron or silicon atoms are expected to absorb the X-rays. One of the spectra showing absorption by iron -- the dips on the left and right -- is included in the main graphic. An additional graphic shows a spectrum with absorption by silicon. In both spectra the data are shown in grey and a computer model in red.

However, the wavelengths of these characteristic signatures of iron and silicon were shifted to longer, or redder wavelengths compared to the laboratory values found here on Earth (shown with the blue, vertical line for each absorption signature). The researchers found that the shift of the absorption features was the same in each of the three Chandra observations, and that it was too large to be explained by motion away from us. Instead they concluded it was caused by gravitational redshift.
The article goes on to explain how gravitational redshifts connect with Einstein's General Theory Relativity: "As predicted by Einstein's theory, clocks under the force of gravity run at a slower rate than clocks viewed from a distant region experiencing weaker gravity. This means that clocks on Earth observed from orbiting satellites run at a slower rate. To have the high precision needed for GPS, this effect needs to be taken into account or there will be small differences in time that would add up quickly, calculating inaccurate positions..."

The findings have been published in the Astrophysical Journal.
NASA

Voyager Spacecraft Detect An Increase In the Density of Space Outside the Solar System 88

As Voyager 2 moves farther and farther from the Sun, the density of space is increasing. "It's not the first time this density increase has been detected," notes SciencAlert. "Voyager 1, which entered interstellar space in 2012, detected a similar density gradient at a separate location." From the report: Voyager 2's new data show that not only was Voyager 1's detection legit, but that the increase in density may be a large-scale feature of the very local interstellar medium (VLIM). The Solar System's edge can be defined by a few different boundaries, but the one crossed by the Voyager probes is known as the heliopause, and it's defined by the solar wind.
[...]
One theory is that the interstellar magnetic field lines become stronger as they drape over the heliopause. This could generate an electromagnetic ion cyclotron instability that depletes the plasma from the draping region. Voyager 2 did detect a stronger magnetic field than expected when it crossed the heliopause. Another theory is that material blown by the interstellar wind should slow as it reaches the heliopause, causing a sort of traffic jam. This has possibly been detected by outer Solar System probe New Horizons, which in 2018 picked up the faint ultraviolet glow resulting from a buildup of neutral hydrogen at the heliopause. It's also possible that both explanations play a role. Future measurements taken by both Voyager probes as they continue their journey out into interstellar space could help figure it out. But that might be a long bet to take.
The findings have been published in The Astrophysical Journal Letters.
Space

Looking for Life? Researchers Identify 24 Exoplanets Even More Habitable Than Earth (gizmodo.com.au) 62

"Astrobiologists have identified 24 exoplanets that aren't just potentially habitable, they're potentially superhabitable, exhibiting an array of conditions more suitable to life than what's seen on Earth..." reports Gizmodo: For exoplanets to be superhabitable, they should be older, larger, heavier, warmer, and wetter compared to Earth, and ideally located around stars with longer lifespans than our own. So yeah, not only is Earth inferior, so too is our Sun, according to the new research...

As the new study points out, planets marginally older than Earth have a greater chance of being more habitable. When planets get old, "exhaustion of internally generated heat may result in eventual cooling, with consequences for global temperatures and atmospheric composition," write the authors. Earth is 4.5 billion years old, but planets between the ages of 5 billion and 8 billion years are likely to be more habitable, simply from a probabilistic standpoint...

To be clear, many of the criteria, such as atmospheric oxygen, plate tectonics, geomagnetism, and natural satellites, are currently beyond our ability to detect. What's more, only two of these planets, Kepler 1126 b and Kepler-69c, are scientifically validated planets, the remainder being on the list of unconfirmed Kepler Objects of Interest. Consequently, some of these "exoplanets" might not even be planets at all...

There are other limitations to consider as well. The authors are naturally biased towards Earth-like conditions, given that our planet provides the only known example of habitability. Life may proliferate under conditions not yet understood, and it's important to keep that in mind... We also don't know about the potential knock-off effects of these conditions. They sound good on paper, but the reality could be vastly different, as these environmental characteristics could collectively result in conditions wholly unsuitable for life.

"What's useful here is the criteria for planets that may not look exactly like Earth, but could be even more awesome locations for life," writes CNET.

"This could help us direct the resources of next-generation space telescopes like NASA's much-delayed James Webb."
Space

Physicists Argue That Black Holes From the Big Bang Could Be the Dark Matter (quantamagazine.org) 85

Long-time Slashdot reader fahrbot-bot quotes Quanta magazine: It was an old idea of Stephen Hawking's: Unseen "primordial" black holes might be the hidden dark matter. It fell out of favor for decades, but a new series of studies has shown how the theory can work...

Their very blackness makes it hard to estimate how many black holes inhabit the cosmos and how big they are. So it was a genuine surprise when the first gravitational waves thrummed through detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in September 2015. Previously, the largest star-size black holes had topped out at around 20 times the mass of the sun. These new ones were about 30 solar masses each — not inconceivable, but odd. Moreover, once LIGO turned on and immediately started hearing these sorts of objects merge with each other, astrophysicists realized that there must be more black holes lurking out there than they had thought. Maybe a lot more.

The discovery of these strange specimens breathed new life into an old idea — one that had, in recent years, been relegated to the fringe. We know that dying stars can make black holes. But perhaps black holes were also born during the Big Bang itself. A hidden population of such "primordial" black holes could conceivably constitute dark matter, a hidden thumb on the cosmic scale...

Following a flurry of recent papers, the primordial black hole idea appears to have come back to life. In one of the latest, published last week in the Journal of Cosmology and Astroparticle Physics, Karsten Jedamzik, a cosmologist at the University of Montpellier, showed how a large population of primordial black holes could result in collisions that perfectly match what LIGO observes. "If his results are correct — and it seems to be a careful calculation he's done — that would put the last nail in the coffin of our own calculation," said Ali-Haïmoud, who has continued to play with the primordial black hole idea in subsequent papers too. "It would mean that in fact they could be all the dark matter."

"It's exciting," said Christian Byrnes, a cosmologist at the University of Sussex who helped inspire some of Jedamzik's arguments. "He's gone further than anyone has gone before...." And with every subsequent observing run, LIGO has increased its sensitivity, allowing it to eventually either find such small black holes or set strict limits on how many can exist. "This is not one of these stories like string theory, where in a decade or three decades we might still be discussing if it's correct," Byrnes said.

Moon

Astronomers Discover Possible 60s-Era Moon Rocket Booster Heading Back To Earth (teslarati.com) 66

An anonymous reader quotes Teslarati: On August 19th this year, astronomers using the Panoramic Survey Telescope and Rapid Response System observatory in Hawaii spotted an object destined to enter Earth orbit this fall. Designated as object 2020 SO, the item is now believed to be a rocket booster from NASA's Surveyor 2 mission which crash landed on the Moon in 1966 during the Apollo-era of the Cold War's space race.

"I suspect this newly discovered object 2020 SO to be an old rocket booster because it is following an orbit about the Sun that is extremely similar to Earth's, nearly circular, in the same plane, and only slightly farther away the Sun at its farthest point," Dr. Paul Chodas, the director of NASA's Center for Near Earth Object Studies, explained in comments to CNN.

"That's precisely the kind of orbit that a rocket stage separated from a lunar mission would follow, once it passes by the Moon and escapes into orbit about the Sun. It's unlikely that an asteroid could have evolved into an orbit like this, but not impossible," he said. This specific type of event has only happened once before, namely in 2002 with a Saturn V upper stage from Apollo 12, according to Dr. Chodas.

Space

The Only Black Hole We've Ever Seen Has a Shadow That Wobbles (technologyreview.com) 22

The supermassive black hole at the center of the M87 galaxy has a shadow crescent that moves, like a dancer in the dark. From a report: Over a year ago, scientists unleashed something incredible on the world: the first photo of a black hole ever taken. By putting together radio astronomy observations made with dishes across four continents, the collaboration known as the Event Horizon Telescope managed to peer 53 million light-years away and look at a supermassive black hole, which is 6.5 million times the mass of the sun and sits at the center of the galaxy Messier 87 (M87). The fiery historic image showed off a bright crescent of ultra-hot gas and debris orbiting the black hole's event horizon, the pitch-black central point-of-no-return that traps anything that goes over, even light. The EHT team had just made one of the most impressive achievements in the history of astronomy, but this was only the beginning. On Wednesday, members of the EHT collaboration published new findings in the Astrophysical Journal about M87's supermassive black hole (known as M87*), revealing two new major insights.

First, the shadow diameter of the event horizon doesn't change over time, which is exactly what Einstein's theory of general relativity predicts for a supermassive black hole of M87*'s size. However, the second insight is that the bright crescent adorning this shadow is far from stable: it wobbles. There's so much turbulent matter surrounding M87* that it makes sense the crescent would bug out and get fidgety. But the fact that we can watch it over time means we now have an established method for studying the physics of one of the most extreme kinds of environment in the entire universe.

Java

Oracle's Plan to Keep Java Developers from Leaving for Rust and Kotlin (zdnet.com) 90

ZDNet reports: Oracle has released version 15 of Java, the language created 25 years ago by James Gosling at Sun Microsystems, which Oracle snapped up in 2009 for about $7.4bn to gain what it said was the "most important software Oracle has ever acquired". Java 15, or Oracle Java Development Kit (JDK) 15, brings the Edwards-Curve digital signature algorithm, hidden classes, and former preview features that have been finalized, including text blocks, and the Z Garbage Collector, while the sealed-classes feature arrives and pattern matching and records emerge as a second preview...

In July, Java fell out of RedMonk's top two positions for the first time since 2012 and now resides behind JavaScript and Python in terms of popularity. Tiobe in September ranked Java in second position, behind C and ahead of Python.... But Java is still hugely popular and widely used in the enterprise, according to Oracle, which notes it is used by over 69% of full-time developers worldwide... It counts Arm, Amazon, IBM, Intel, NTT Data, Red Hat, SAP and Tencent among its list of notable contributors to JDK 15. Oracle also gave a special mention to Microsoft and cloud system monitoring service DataDog for fixes...

As part of Java's 25th anniversary, Oracle commissioned analyst firm Omdia to assess its six-month release strategy for Java and whether it would be enough to keep millions of Java developers away from memory-safe alternatives such as Kotlin, the language Google has endorsed for Android development, and Rust, a system programming language that was created at Mozilla. "In Omdia's opinion, the work Oracle began a few years ago in moving to a six-month update cycle and introducing a new level of modularity, puts the vendor in good stead with its constituency of approximately 12 million developers," Oracle said in its report on Omdia's analysis.

"However, Oracle and the Java programming language need an ongoing series of innovative, must-have, and 'delightful' features that make the language even more user friendly and cloud capable. These will keep existing Java developers happy while steering potential Java developers away from newer languages like Rust and Kotlin."

Space

Venus Might Host Life, New Discovery Suggests (scientificamerican.com) 55

There is something funky going on in the clouds of Venus. Telescopes have detected unusually high concentrations of the molecule phosphine -- a stinky, flammable chemical typically associated with feces, farts and rotting microbial activity -- in an atmospheric layer far above the planet's scorching surface. From a report: The finding is curious because here on Earth, phosphine is essentially always associated with living creatures, either as a by-product of metabolic processes or of human technology such as industrial fumigants and methamphetamine labs. Although toxic to many organisms, the molecule has been singled out as a potentially unambiguous signature of life because it is so difficult to make through ordinary geological or atmospheric action. Swathed in sulfuric acid clouds and possessing oppressive surface pressures and temperatures hot enough to melt lead, Venus is a hellish world. But the particular cloud layer where the phosphine is present happens to be relatively balmy, with ample sunlight and Earth-like atmospheric pressure and temperature. The results will have to be carefully vetted by the scientific community. Yet they seem likely to spark renewed interest in exploring our sister planet next door.

"It's a really puzzling discovery because phosphine doesn't fit in our conception of what kinds of chemicals should be in Venus's atmosphere," says Michael Wong, an astrobiologist at the University of Washington. Planetary scientist Sanjay Limaye of the University of Wisconsin-Madison agrees. "The bottom line is we don't know what's going on," he says. (Neither Wong nor Sanjay were involved in the work.) After the sun and moon, Venus is the brightest object visible to the naked eye in Earth's sky. For thousands of years, people told stories about the glittering jewel that appeared around sunrise and sunset. Venus's brilliance is what made it attractive to Jane Greaves, a radio astronomer at Cardiff University in England. She typically focuses her attention on distant newborn planetary systems but wanted to test her molecular identification abilities on worlds within our cosmic backyard. In 2017 Greaves observed Venus with the James Clerk Maxwell Telescope (JCMT) on Mauna Kea in Hawaii, searching for bar code-like patterns of lines in the planet's spectrum that would indicate the presence of different chemicals. While doing so, she noticed a line associated with phosphine. The data suggested the molecule was present at around 20 parts per billion in the planet's atmosphere, a concentration between 1,000 and a million times greater than that in Earth's atmosphere. "I was stunned," Greaves says.
Further reading: The original paper in the journal Nature Astronomy; and the case for life on Venus.
Google

Google Reverses Lifelong Carbon Emissions To Fight Climate Change (cnet.com) 38

A few months after Microsoft pledged to undo by 2050 the climate harm it's done to the atmosphere by emitting carbon dioxide into the atmosphere, Google said it's already done so. "We have eliminated Google's entire carbon legacy," Chief Executive Sundar Pichai said Monday in a blog post. From a report: Carbon dioxide, which can trap heat from the sun in the earth's atmosphere in a process called the greenhouse effect, is a key part of climate change problems humans are causing on the planet. Google said it became carbon neutral in 2007, meaning it offset carbon emissions related to its operations. That's typically done by purchasing "carbon offsets," actions like planting trees, but carbon offsets are a complex and sometimes shady business. The search and Android giant reversed its carbon footprint by buying "high-quality" carbon offsets, Pichai said. Carbon emissions are a major issue for companies seeking to become more environmentally responsible. Google has long pushed for sustainable operations. That's easier at a profitable tech giant, though, than at a more conventional business.
Space

Is Planet Nine a Black Hole? (nytimes.com) 105

"Astrophysicists have recently begun hatching plans to find out just how weird Planet Nine might be," reports the New York Times. Long-time Slashdot reader fahrbot-bot shares their report: Although it is probably wishful thinking, some astronomers contend that a black hole may be lurking in the outer reaches of our solar system. All summer, they have been arguing over how to find it, if indeed it is there, and what to do about it, proposing plans that are only halfway out of this world...

Earlier this year, Edward Witten, a theoretical physicist at the Institute for Advanced Study in Princeton, chimed in... Dr. Witten suggested borrowing a trick from Breakthrough Starshot, the proposal by Russian philanthropist Yuri Milner and Dr. Hawking to send thousands of laser-propelled microscopic probes to the nearest star system, Alpha Centauri. Dr. Witten suggested sending hundreds of similarly small probes outward in all directions to explore the solar system. By keeping track of incoming signals from the probes, scientists on Earth would be able to tell if and when each one sped up or slowed down as it encountered the gravitational field of Planet Nine or anything else out there.

Key to this plan would be the ability of the probes to keep pinging Earth precisely every hundred-thousandth of a second. In May, astronomers Scott Lawrence and Zeeve Rogoszinski of the University of Maryland suggested instead monitoring the trajectories of the probes with high-resolution radio telescopes, which would obviate the need for high-precision clocks on the probes.

Another idea came from Avi Loeb, chair of the astronomy department at Harvard and leader of a scientific advisory board for Breakthrough Starshot: in July Dr. Loeb was back, with a student, Amir Siraj, and a new idea for finding the Planet Nine black hole. If a black hole were out there, they argued, it would occasionally rip apart small comets, causing bright flares that could soon be spotted by the new Vera C. Rubin Observatory, previously known as the Large Synoptic Survey Telescope, now under construction in Chile. The observatory's mission, starting in 2021, is to make a movie of the universe, producing a panorama of the entire southern night sky every few days and revealing anything that has changed or moved. Such flares should occur a few times a year, they noted. "Our calculations show that the flares will be bright enough for the Vera Rubin Observatory to rule out or confirm Planet Nine as a black hole within one year of monitoring the sky with its L.S.S.T. survey," Dr. Loeb wrote in an email.

Moreover, because the Rubin telescope examines such a large swath of sky, it could detect or rule out black holes of similar size all the way out to the Oort cloud, a vague and diffuse assemblage of protocomets and primordial, frozen riffraff a trillion miles from the sun, they said.

The prospect of finding a black hole in our own solar system "is as startling as finding evidence that someone might be living in the shed in your backyard," Dr. Loeb said in the email. "If so, who is it, and how did it get there?"

Power

Researchers Use Supercomputer to Design New Molecule That Captures Solar Energy (liu.se) 36

A reader shares some news from Sweden's Linköping University: The Earth receives many times more energy from the sun than we humans can use. This energy is absorbed by solar energy facilities, but one of the challenges of solar energy is to store it efficiently, such that the energy is available when the sun is not shining. This led scientists at Linköping University to investigate the possibility of capturing and storing solar energy in a new molecule.

"Our molecule can take on two different forms: a parent form that can absorb energy from sunlight, and an alternative form in which the structure of the parent form has been changed and become much more energy-rich, while remaining stable. This makes it possible to store the energy in sunlight in the molecule efficiently", says Bo Durbeej, professor of computational physics in the Department of Physics, Chemistry and Biology at LinkÃping University, and leader of the study...

It's common in research that experiments are done first and theoretical work subsequently confirms the experimental results, but in this case the procedure was reversed. Bo Durbeej and his group work in theoretical chemistry, and conduct calculations and simulations of chemical reactions. This involves advanced computer simulations, which are performed on supercomputers at the National Supercomputer Centre, NSC, in Linköping. The calculations showed that the molecule the researchers had developed would undergo the chemical reaction they required, and that it would take place extremely fast, within 200 femtoseconds. Their colleagues at the Research Centre for Natural Sciences in Hungary were then able to build the molecule, and perform experiments that confirmed the theoretical prediction...

"Most chemical reactions start in a condition where a molecule has high energy and subsequently passes to one with a low energy. Here, we do the opposite — a molecule that has low energy becomes one with high energy. We would expect this to be difficult, but we have shown that it is possible for such a reaction to take place both rapidly and efficiently", says Bo Durbeej.

The researchers will now examine how the stored energy can be released from the energy-rich form of the molecule in the best way...

Programming

'If Everyone Hates Object-Oriented Programming, Why Is It Still So Widely Spread?' (stackoverflow.blog) 386

Object-oriented programming "has been wildly successful. But was the success just a coincidence?" asks Stack Overflow's blog: Asking why so many widely-used languages are OOP might be mixing up cause and effect. Richard Feldman argues in his talk that it might just be coincidence. C++ was developed in the early 1980s by Bjarne Stroustrup, initially as a set of extensions to the C programming language. Building on C , C++ added object orientation but Feldman argues it became popular for the overall upgrade from C including type-safety and added support for automatic resource management, generic programming, and exception handling, among other features.

Then Java wanted to appeal to C++ programmers and doubled down on the OOP part. Ultimately, Sun Microsystems wanted to repeat the C++ trick by aiming for greatest familiarity for developers adopting Java. Millions of developers quickly moved to Java due to its exclusive integration in web browsers at the time. Seen this way, OOP seems to just be hitching a ride, rather than driving the success.

While acknowledging OOP cornerstones like encapsulation, inheritance, polymorphism, the article still takes a skeptical stance. "Seems like in 2020, there is not so much that OOP can do that other programming paradigms cannot, and a good programmer will use strategies from multiple paradigms together in the battle against complexity."
NASA

Volunteers Spot Almost 100 Cold Brown Dwarfs Near Our Sun (space.com) 36

Citizen scientists have spotted almost 100 of our sun's nearest neighbors. Space.com reports: In a new study, members of the public -- including both professional scientists and volunteers -- discovered 95 brown dwarfs (celestial objects too big to be considered planets and too small to be considered stars) near our sun through the NASA-funded citizen science project Backyard Worlds: Planet 9. They made this discovery with the help of astronomers using the National Science Foundations National Optical-Infrared Astronomy Research Laboratory. Brown dwarfs are unusual celestial objects -- much heavier than planets but not massive enough to become stars. The celestial objects can be seriously hot (think thousands of degrees Fahrenheit), but these 95 newly-discovered neighbors are surprisingly cool. Some of these weird worlds are even relatively close to Earth's temperature and could be cool enough to have water clouds in their atmospheres, according to the statement.
Earth

A Car-Sized Asteroid Made the Closest Earth Flyby a Space Rock Has Ever Survived (space.com) 56

New submitter louisfreeman shares a report from Space.com: A newly discovered car-sized asteroid just made the closest-known flyby to Earth without hitting our planet. On Sunday (Aug. 16), the asteroid, initially labeled ZTF0DxQ and now formally known to astronomers as 2020 QG, swooped by Earth at a mere 1,830 miles (2,950 kilometers) away. That gives 2020 QG the title of closest asteroid flyby ever recorded that didn't end with the space rock's demise. What's slightly concerning is the fact that the flyby wasn't expected.

The Palomar Observatory didn't detect the zooming asteroid until about six hours after the object's closest approach. "The asteroid approached undetected from the direction of the sun," Paul Chodas, the director of NASA's Center for Near Earth Object Studies, told Business Insider. "We didn't see it coming."
Power

Transparent Solar Panels For Windows Hit Record 8% Efficiency (umich.edu) 60

Bodhammer shares a report from the University of Michigan: In a step closer to skyscrapers that serve as power sources, a team led by University of Michigan researchers has set a new efficiency record for color-neutral, transparent solar cells. The team achieved 8.1% efficiency and 43.3% transparency with an organic, or carbon-based, design rather than conventional silicon. While the cells have a slight green tint, they are much more like the gray of sunglasses and automobile windows.

The new material is a combination of organic molecules engineered to be transparent in the visible and absorbing in the near infrared, an invisible part of the spectrum that accounts for much of the energy in sunlight. In addition, the researchers developed optical coatings to boost both power generated from infrared light and transparency in the visible range -- two qualities that are usually in competition with one another. The color-neutral version of the device was made with an indium tin oxide electrode. A silver electrode improved the efficiency to 10.8%, with 45.8% transparency. However, that version's slightly greenish tint may not be acceptable in some window applications.

Both versions can be manufactured at large scale, using materials that are less toxic than other transparent solar cells. The transparent organic solar cells can also be customized for local latitudes, taking advantage of the fact that they are most efficient when the sun's rays are hitting them at a perpendicular angle. They can be placed in between the panes of double-glazed windows. [The team is] working on several improvements to the technology, with the next goal being to reach a light utilization efficiency of 7% and extending the cell lifetime to about 10 years. They are also investigating the economics of installing transparent solar cell windows into new and existing buildings.
The research has been published in the journal Proceedings of the National Academy of Sciences.
NASA

NASA Is Tracking a Vast, Growing Anomaly In Earth's Magnetic Field (sciencealert.com) 59

fahrbot-bot shares a report from ScienceAlert: NASA is actively monitoring a strange anomaly in Earth's magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa. This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers. The space agency's satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.

The primary source is considered to be a swirling ocean of molten iron inside Earth's outer core, thousands of kilometers below the ground. A huge reservoir of dense rock called the African Large Low Shear Velocity Province, located about 2,900 kilometers (1,800 miles) below the African continent, disturbs the field's generation, resulting in the dramatic weakening effect -- which is aided by the tilt of the planet's magnetic axis. It's not just moving, however. Even more remarkably, the phenomenon seems to be in the process of splitting in two, with researchers this year discovering that the SAA appears to be dividing into two distinct cells, each representing a separate centre of minimum magnetic intensity within the greater anomaly. Just what that means for the future of the SAA remains unknown, but in any case, there's evidence to suggest that the anomaly is not a new appearance.

Sun Microsystems

CNO Neutrinos From the Sun Are Finally Detected (syfy.com) 32

An anonymous reader quotes a report from SyFy: For the first time, scientists have detected neutrinos coming from the Sun's core that got their start via the CNO process, an until-now theorized type of stellar nuclear fusion. [...] The Borexino neutrino observatory is 1400 meters under the rock below the Gran Sasso mountain in Italy. It has an 8.5 meter wide nylon balloon filled with 280 tons of pseudocumene, surrounded by a tank of water, surrounded by over 2200 very sensitive photon detectors. They turned everything on, then waited. Over the course of July 2016 - February 2020 (1072 days), they painstakingly recorded all the events, and had to go through heroic efforts to prevent all manners of other reactions that also create little light flashes from interfering with their experiment. They also had to distinguish proton-proton chain neutrinos from ones made in the CNO cycle, but the neutrinos have different energies, which makes it possible to separate them out. They just announced their results: They detected the CNO neutrinos! About 20 per day interacted with the pseudocumene -- 20 per day, when sextillions of them had passed through! -- about what you'd expect from theory.

This is an important discovery for a lot of reasons. For one thing, while the proton-proton chain dominates in the Sun, in stars with more than about 1.3 times the Sun's mass the CNO cycle dominates (it kicks in strongly at higher temperatures), so knowing how it works in the Sun tells us about other stars. Also, the presence of heavier elements (what astronomers misleadingly call metals, meaning any element heavier than hydrogen and helium) can affect the fusion rate in the Sun's CNO cycle, and the amount of these metals isn't perfectly well known; different methods to measure them yield slightly different amounts, but enough to mess up what we know about the fusion in the core. This experiment agrees with ones that find a lower metal content. That has a ripple effect on a lot of other ideas, including details on how we think the Sun and planets formed, how the Sun ages, and how it will die. All that, from less than two dozen neutrinos a day, while countless more go undetected.

Earth

Scientists Spot Space Junk With Lasers In Broad Daylight 37

Researchers from the Institute for Space Research at the Austrian Academy of Sciences have developed a technique in which lasers can measure the position of space debris during daylight conditions. Details of this unprecedented achievement were published in Nature Communications. Gizmodo reports: Prior to this, lasers could only detect space junk during twilight, as ground stations enter into darkness and objects near the horizon remain illuminated by the Sun's rays. This small window of opportunity severely minimizes the amount of time available to search for and characterize these orbiting objects, which can threaten crucial satellites.

"We are used to the idea that you can only see stars at night, and this has similarly been true for observing debris with telescopes, except with a much smaller time window to observe low-orbit objects," explained Tim Flohrer, Head of ESA's Space Debris Office, in an ESA press release. "Using this new technique, it will become possible to track previously 'invisible' objects that had been lurking in the blue skies, which means we can work all day with laser ranging to support collision avoidance." The new technique differs from conventional methods in that it can track objects during daylight hours, which it does using a combination of telescopes, light deflectors, and filters that track light at specific wavelengths. So even when the sky is bright and blue, scientists can increase a target's contrast, making previously invisible objects visible. Keys to this method include additional telescopes and the ability to visualize space debris against the blue sky background in real-time. In daylight tests, the distances to 40 different objects were measured with the new technique, which had never been done before.
Space

Spacecraft Made From Ultra Thin Foam Could Reach Proxima Centauri In 185 Years (newsweek.com) 155

An anonymous reader quotes Newsweek: A hypothetical spacecraft made from an extremely thin layer of a synthetic foam could technically make it to our closest neighboring star Proxima Centauri in just 185 years, scientists have said. If Voyager were to make the same journey, it would take around 73,000 years, according to NASA.

In a study that is due to be published in the journal Astronomy & Astrophysics, René Heller from the Max Planck Institute for Solar System Research, Germany, and colleagues, propose the spacecraft as a precursor to interstellar travel — beyond our own solar system. They estimate a prototype would cost around $1 million, while the launch of an interplanetary mission would be around $10 million.

The spacecraft would be made from aerographite. This is a carbon-based foam that is around 15,000 times more lightweight than aluminium. It is versatile and light enough that it could be used to create solar sails — "which harness energy from the sun for propulsion, a process called solar photon pressure... In most cases, photons would have little impact on an object. But if the target is an ultralight material, such as aerographite, then the target can actually be pushed to significant speed," he said.

"We found out that a thin layer of aerographite, with a thickness of about 1 millimeter (0.04 inches), can be pushed to speeds that are sufficiently high to let it escape the solar system. Once it has gained an initial push from the solar radiation pressure, it will simply float through space...."

Heller said these spacecraft could travel far faster than any probe ever sent by humans before.

Displays

William English, Engineer Behind 'The Mother of All Demos', Dies at 91 (msn.com) 18

An anonymous reader quotes The Los Angeles Times: On Dec. 9, 1968, the then-small world of computer engineering was shaken to its core by a presentation of new technologies projected onto a screen in a San Francisco hall. The attendees at the historic event saw demonstrations of video conferencing, the first public use of a computer mouse, hyperlinking in which clicking a word in a document transported the user to an entirely new document — and more. The man who was the star of the hands-on show seen in the hall was Douglas Engelbart, whose team at the research center SRI in Menlo Park, California, had been developing them for years.

But the man who had designed what is known now as "The Mother of All Demos" and was working behind the scenes to make sure they all worked was William K. English, who died Sunday at the age of 91. Bill English played an indispensable role in more than Engelbart's demo... In 1965 the lab received a NASA grant to invent a technology for moving a cursor and selecting an item on a display screen; Engelbart developed the concept, but it was English who designed the first prototype &mdash the mouse...

English essentially choreographed Engelbart's presentation. Just as important, he made sure there were no technical glitches. That was a challenge, since Engelbart would be in San Francisco demonstrating a system that was being operated 30 miles away in Menlo Park, the two sites connected via a microwave relay. The event went off virtually without a hitch, and a new world was born. "Doug wasn't doing it," recalls Roberta, who had worked as Engelbart's secretary. "It was all Bill." Engelbart died in 2013.

English also participated in an early research project "into the psychological effects of LSD," according to the article.

But a few years after the legendary demo, English was recruited for Xerox's legendary Palo Alto Research Center, "where he helped midwife PARC's invention of the personal computer and other innovations... He subsequently left Xerox to join Sun Microsystems and later the pioneering electronic game console maker 3DO."

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