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  • richardmitnick 1:14 pm on September 17, 2021 Permalink | Reply
    Tags: "High-speed internet via airborne beams of light", BBC UK   

    From BBC (UK) : “High-speed internet via airborne beams of light” 

    From BBC (UK)

    Jane Wakefield

    Getting broadband over the Congo is a challenge. Credit: Getty Images.

    A novel way of delivering high-speed internet via beams of light through the air has successfully transmitted data across the Congo River.

    It means that citizens in Brazzaville and Kinshasa could get faster and cheaper broadband.

    Project Taara is one of Alphabet X’s (formerly Google X) so-called moonshot ideas.

    It grew out of Project Loon, a broadband project using balloons in the stratosphere, since shut down.

    The latest experiment means that a “particularly stubborn connectivity gap” between the two African cities – Brazzaville in the Republic of the Congo and Kinshasa in the Democratic Republic of Congo – has been filled, said the team in a blog.

    The cities lie only three miles apart but connecting them is tricky because traditional cable has to be routed around the river, making broadband prices five times more expensive.

    The hardware includes pointing and tracking beacons that beam light to each other across distance. Credit: Alphabet X.

    The wireless optical communications (WOC) system provided nearly 700 terabytes of data in 20 days with 99.9% availability, the team at X reported.

    “While we don’t expect to see perfect reliability in all kinds of weather and conditions in future, we’re confident Taara’s links will continue to deliver similar performance and will play a key role in bringing fast, more affordable connectivity to the 17 million people living in these cities,” it said in the blog.

    It is the latest iteration of the project which has been in development for three years. X is working with Econet Group and Liquid Telecom to bring high-speed internet to sub-Saharan Africa and has begun a commercial rollout in Kenya.

    The system uses very narrow, invisible beams of light to deliver high speeds, similar to the way traditional fibre in the ground uses light to carry data but without the cable casing.

    The technology, known as Free Space Optical Communications, grew out of experiments the team had previously used to beam lasers between balloons in Project Loon, which was shut down by Alphabet in February because it was no longer seen as commercially viable.

    It is not perfect and the team admits it will not offer full reliability in challenging conditions, such as fog, haze or when birds fly in front of the signal.

    The system does not work well in conditions that may interrupt the beam of light. Credit: Alphabet X.

    But it has been improved by adjusting the level of laser power being transmitted, which works a bit like a telescope, relying on mirrors, lights, software and hardware to move the beam to exactly where it needs to be. The team have also found ways to reduce errors due to interruptions such as birds flying through the link.

    “While places like foggy San Francisco may never be an ideal spot to use WOC, there are many, many places around the world with ideal weather conditions for Taara’s links,” the blog read.

    The technology has also been trialled in Kenya, India, the US and Mexico.

    See the full article here .


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  • richardmitnick 2:56 pm on January 3, 2021 Permalink | Reply
    Tags: "How a silence solved the weird maths inside black holes", “The singularity problem”, BBC UK, , By the 1950s Albert Einstein’s theory of General Relativity was wildly successful but many of its predictions were still regarded as improbable and untestable., Katie Bouman and Messier 87*, , Roger Penrose-Nobel Prize winner   

    From BBC (UK): “How a silence solved the weird maths inside black holes” 

    From BBC (UK)

    8th October 2020 [From Year End Wrap Up]
    Patchen Barss

    Theoretical physicist Roger Penrose had a moment’s inspiration that upended our view of the Universe, writes his biographer Patchen Barss.

    Roger Penrose has been awarded the Nobel Prize in Physics for his work on singularities. Credit: Alamy.

    On a crisp September day in 1964, Roger Penrose had a visit from an old friend. The British cosmologist Ivor Robinson was back in England from Dallas, Texas, where he lived and worked. Whenever the two met up, they never lacked for conversation, and their talk on this occasion was non-stop and wide ranging.

    As the pair walked near Penrose’s office at Birkbeck College in London, they paused briefly on the curb, waiting for a break in the traffic. The momentary halt in their stroll coincided with a lull in conversation and they fell into silence as they crossed the road.

    In that moment, Penrose’s mind drifted. It travelled 2.5 billion light years through the vacuum of outer space to the seething mass of a whirling quasar. He imagined how gravitational collapse was taking over, pulling an entire galaxy in deeper and closer to the centre. Like a twirling figure skater pulling their arms in close to their body, the mass would spin more and more quickly as it contracted.

    This brief mental flicker led to a revelation – one that 56 years later would win him the Nobel Prize in Physics. ­

    Like many relativists — theoretical physicists working to test, explore and extend Albert Einstein’s General Theory of Relativity — Penrose had spent the early 1960s studying a strange, but particularly knotty contradiction known as “the singularity problem”.

    Einstein published his General Theory in 1915, revolutionising scientists’ understanding of space, time, gravity, matter and energy. By the 1950s, Einstein’s theory was wildly successful, but many of its predictions were still regarded as improbable and untestable. His equations showed, for instance, that it was theoretically possible for gravitational collapse to force enough matter into a sufficiently small region that it would become infinitely dense, forming a “singularity” from which not even light could escape. These became known as black holes.

    But within such a singularity, the known laws of physics — including Einstein’s own theory of relativity that predicted it — would no longer apply.

    Singularities were fascinating to mathematical relativists for this very reason. Most physicists, however, agreed our Universe was too orderly to actually contain such regions. And even if singularities did exist, there would be no way to observe them.

    “There was huge scepticism for a long time,” says Penrose. “People expected there to be a bounce: that an object would collapse and swirl around in some complicated way, and come swishing back out again.”

    In the late 1950s, observations from the emerging field of radio astronomy threw these ideas into turmoil. Radio astronomers detected new cosmic objects that appeared to be very bright, very distant and very small. First known as “quasi-stellar objects” – later shortened to “quasars” – these objects appeared to exhibit too much energy in too small a space. While it seemed impossible, every new observation pointed toward the idea that quasars were ancient galaxies in the process of collapsing into singularities.

    Scientists were forced to ask themselves whether singularities were not as unlikely as everyone thought? Was this prediction of relativity more than just a mathematical flight of fancy?

    In Austin, Princeton, and Moscow, at Cambridge and Oxford, in South Africa, New Zealand, India, and elsewhere, cosmologists, astronomers, and mathematicians scrambled to find a definitive theory that could explain the nature of quasars.

    Most scientists approached the challenge by trying to identify highly specialised circumstances under which a singularity might form.

    Penrose, then a reader at Birkbeck College in London, took a different approach. His natural instinct had always been to search for general solutions, underlying principles and essential mathematical structures. He spent long hours at Birkbeck, working at a large chalkboard covered in curves and twists of diagrams of his own design.

    In 1963, a team of Russian theorists led by Isaac Khalatnikov published an acclaimed paper that confirmed what most scientists still believed – singularities were not a part of our physical Universe. In the Universe, they said, collapsing dust clouds or stars would indeed expand back out again long before they reached the point of singularity. There had to be some other explanation for quasars.

    Penrose was sceptical.

    The singularity at the heart of a black hole produces heat so intense that extremely bright radiation is blasted out in every direction. Credit: NASA.

    “I had the strong feeling that with the methods they were using, it was unlikely they could have come to a firm conclusion about it,” he says. “It seemed to me the problem needed to be looked at in a more general way than they were doing, which was a somewhat limited focus.”

    Still, while he rejected their arguments, he still could not develop a general solution for the singularity problem. That was until the visit by Robinson. Although Robinson too was researching the singularity problem, the pair didn’t discuss it during their conversation on that autumn day of 1964 in London.

    During the brief quiet of that fateful street crossing, however, Penrose realised that the Russians were wrong.

    All of that energy, movement and mass shrinking together would create a heat so intense that radiation would blast out on every wavelength in every direction. The smaller and faster it got, the brighter it would glow.

    He mentally mapped his chalkboard drawings and journal sketches onto that distant object, searching his mind for the point the Russians’ predicted, where this cloud would explode back out again.

    No such point existed. In his mind’s eye, Penrose at last saw how the collapse would continue unimpeded. Outside the densifying centre, the object would shine with more light than all the stars in our galaxy. And deep within, light would bend at dramatic angles, spacetime warping until every direction converged on every other.

    There would come a point of no return. Light, space and time would all come to a full stop. A black hole.

    At that moment, Penrose knew a singularity didn’t require any special circumstances. In our Universe, singularities weren’t impossible. They were inevitable.

    Stephen Hawking and Roger Penrose worked together to create theories on singularities during the 1970s. Credit: John Cairns/University of Oxford.

    Back on the other side of the street, he picked up his conversation with Robinson, and immediately forgot what he had been thinking about. They bid farewell, and Penrose returned to the chalk clouds and stacks of paper in his office.

    The rest of the afternoon went as normal, except Penrose found himself in an inordinately good mood. He could not figure out why. He began reviewing his day, investigating what might be powering his euphoria.

    His mind returned to that moment of silence crossing the street. And it all came flooding back. He had solved the singularity problem.

    He began writing down equations, testing, editing, rearranging. The argument was still rough, but it all worked. A gravitational collapse required only some very general, easy-to-meet energy conditions, to collapse into infinite density. Penrose knew at that moment there had to be billions of singularities littering the cosmos.

    It was an idea that would upend our understanding of the Universe and shape what we now know about it today.

    Within two months, Penrose had begun giving talks on the theorem. In mid-December, he submitted a paper to the academic journal Physical Review Letters, which was published on 18 January 1965 – just four months after he crossed the street with Ivor Robinson.

    The response was not quite what he hoped. The Penrose Singularity Theorem was debated. Refuted. Contradicted.

    The debate came to a head at the International Congress on General Relativity and Gravity in London later that year.

    “It was not very friendly. The Russians were pretty annoyed, and people were reluctant to admit they were mistaken,” says Penrose. The conference ended with the debate unresolved.

    But not long after, it came out that the Russian paper had errors in its calculations – the mathematics was fatally flawed, their thesis no longer tenable.

    “There was an error in the way they were doing it,” says Penrose.

    By late 1965, the Penrose Singularity Theorem was gaining traction all over the world. His singular flash of insight became a driving force in cosmology. He had done more than explain what a quasar was – he had revealed a major truth about the underlying reality of our Universe. Whatever models of the Universe people came up with from then on had to include singularities, which meant including science that goes beyond relativity.

    Singularities also began to seep into the public consciousness, thanks partly to their becoming known evocatively as “black holes”, a term first used publicly by American science journalist Ann Ewing.

    Stephen Hawking famously built on Penrose’s theorem to upend theories about the origin of the Universe after the pair worked together on singularities [Proceeding of The Royal Society A]. Singularities became central to every theory about the nature, history and future of the Universe. Experimentalists identified other singularities – including the one at the heart of the hypermassive black hole at the centre of our own galaxy discovered by Reinhard Genzel and Andrea Ghez, who shared the Nobel Prize in Physics with Penrose this year.

    Penrose himself went on to develop an alternative to the Big Bang Theory known as Conformal Cyclic Cosmology, the evidence for which could come from the remnant signals from ancient black holes.

    In 2013, engineer and computer scientist Katie Bouman* led a team of researchers which developed an algorithm that they hoped would allow black holes to be photographed.

    Now iconic image of Katie Bouman-Harvard Smithsonian Astrophysical Observatory after the image of Messier 87 was achieved. Headed from Harvard to Caltech as an Assistant Professor. Katie is on the committee for the next iteration of the EHT .

    In April 2019, the Event Horizons telescope used an algorithm to capture the first images of a black hole, providing dramatic visual confirmation of both Einstein’s and Penrose’s once controversial theories.

    EHT map.

    Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration released on 10 April 2019.

    While Penrose, now 89 years old, is pleased to have been awarded the highest honour in physics, the Nobel Prize, but there is something else pressing on his mind.

    “It feels weird. I’ve just been trying to adjust myself. It’s very flattering and a huge honour and much appreciated,” he tells me a few hours after receiving the news. “But on the other hand, I am trying to write three different (scientific) articles at the same time, and this makes it harder than it was before.” The phone, he explains, hasn’t stopped ringing with people congratulating him and journalists asking for interviews. And all that clamour is distracting him from focusing on his latest theories.

    Penrose knows better than anyone the power of silence and the flash of insight it can deliver.

    *It is not correct to say that Katie Bouman’s team’s algorithm was the one which enabled the capture of the image of the event horizon of Messier 87*. Nor is it correct to say that she “led a team of researchers”. She was in fact a very important person in this work and led one of four teams developing the hoped for successful algorithm. Alas, her team’s algorithm was not the winner of this friendly competition. It is correct to say she is “On the committee for the next iteration of the EHT”

    See the full article here .


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  • richardmitnick 1:48 pm on January 3, 2021 Permalink | Reply
    Tags: "What if the Universe has no end?", , , , , BBC UK, , , , In fact it’s possible that time has existed forever., Mirror Universe theory, , , , , Roger Penrose’s “Conformal Cyclic Cosmology” theory (CCC)   

    From BBC (UK): “What if the Universe has no end?” 

    From BBC (UK)

    19th January 2020 [Year End Wrap Up]
    Patchen Barss

    Credit: Getty Images.

    The Big Bang is widely accepted as being the beginning of everything we see around us, but other theories that are gathering support among scientists are suggesting otherwise.

    The usual story of the Universe has a beginning, middle, and an end.

    It began with the Big Bang 13.8 billion years ago when the Universe was tiny, hot, and dense. In less than a billionth of a billionth of a second, that pinpoint of a universe expanded to more than a billion, billion times its original size through a process called “cosmological inflation”.

    Next came “the graceful exit”, when inflation stopped. The universe carried on expanding and cooling, but at a fraction of the initial rate. For the next 380,000 years, the Universe was so dense that not even light could move through it – the cosmos was an opaque, superhot plasma of scattered particles. When things finally cooled enough for the first hydrogen atoms to form, the Universe swiftly became transparent. Radiation burst out in every direction, and the Universe was on its way to becoming the lumpy entity we see today, with vast swaths of empty space punctuated by clumps of particles, dust, stars, black holes, galaxies, radiation, and other forms of matter and energy.

    Eventually these lumps of matter will drift so far apart that they will slowly disappear, according to some models. The Universe will become a cold, uniform soup of isolated photons.

    The Universe we can currently see is made up of clumps of particles, dust, stars, black holes, galaxies, radiation. Credit: NASA/JPL-Caltech/ESA/CXC/STScI.

    It’s not a particularly dramatic ending, although it does have a satisfying finality.

    But what if the Big Bang wasn’t actually the start of it all?

    Perhaps the Big Bang was more of a “Big Bounce”, a turning point in an ongoing cycle of contraction and expansion. Or, it could be more like a point of reflection, with a mirror image of our universe expanding out the “other side”, where antimatter replaces matter, and time itself flows backwards. (There might even be a “mirror you” pondering what life looks like on this side.)

    Or, the Big Bang might be a transition point in a universe that has always been – and always will be – expanding. All of these theories sit outside mainstream cosmology, but all are supported by influential scientists.

    The growing number of these competing theories suggests that it might now be time to let go of the idea that the Big Bang marked the beginning of space and time. And, indeed, that it may even have an end.

    Many competing Big Bang alternatives stem from deep dissatisfaction with the idea of cosmological inflation.

    Scars left by the Big Bang in a weak microwave radiation that permeates the entire cosmos provides clues about what the early Universe looked like. Credit: NASA.

    “I have to confess, I never liked inflation from the beginning,” says Neil Turok, the former director of the Perimeter Institute for Theoretical Physics in Waterloo, Canada.

    “The inflationary paradigm has failed,” adds Paul Steinhardt, Albert Einstein professor in science at Princeton University, and proponent of a “Big Bounce” model.

    “I always regarded inflation as a very artificial theory,” says Roger Penrose, emeritus Rouse Ball professor of mathematics at Oxford University. “The main reason that it didn’t die at birth is that it was the only thing people could think of to explain what they call the ‘scale invariance of the Cosmic Microwave Background temperature fluctuations’.”

    The Cosmic Microwave Background (or “CMB”) has been a fundamental factor in every model of the Universe since it was first observed in 1965.

    CMB per ESA/Planck.

    It’s a faint, ambient radiation found everywhere in the observable Universe that dates back to that moment when the Universe first became transparent to radiation.

    The CMB is a major source of information about what the early Universe looked like. It is also a tantalising mystery for physicists. In every direction scientists point a radio telescope, the CMB looks the same, even in regions that seemingly could never have interacted with one another at any point in the history of a 13.8 billion-year- old universe.

    “The CMB temperature is the same on opposite sides of the sky and those parts of the sky would never have been in causal contact,” says Katie Mack, a cosmologist at North Carolina State University. “Something had to connect those two regions of the Universe in the past. Something had to tell that part of the sky to be the same temperature as that part of the sky.”

    Without some mechanism to even out the temperature across the observable Universe, scientists would expect to see much larger variations in different regions.

    Inflation offers a way to solve this so-called “homogeneity problem”. With a period of insane expansion stretching out the Universe so rapidly that almost the entire thing ended up far beyond the region we can observe and interact with. Our observable universe expanded from one tiny homogeneous region within that primordial hot mess, producing the uniform CMB. Other regions beyond what we can observe might look very different.

    Theoretical physicists are increasingly finding that inflation theory fails to account for the spread of matter and energy observed in the Universe. Credit: NASA, ESA.

    “Inflation seems to be the thing that has enough support from the data that we can take it as the default,” says Mack. ”It’s the one I teach in my classes. But I always say that we don’t know for sure that this happened. But it seems to fit the data pretty well, and is what most people would say is most likely.”


    Alan Guth, from Highland Park High School and M.I.T., who first proposed cosmic inflation

    HPHS Owls

    Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes
    Alex Mittelmann, Coldcreation

    Alan Guth’s notes:

    Alan Guth’s original notes on inflation

    But there have always been shortcomings with the theory. Notably, there is no definitive mechanism to trigger inflationary expansion, or a testable explanation for how the graceful ending could happen. One idea put forward by proponents of inflation is that theoretical particles made up something called an “inflation field” that drove inflation and then decayed into the particles we see around us today.

    But even with tweaks like this, inflation makes predictions that have, at least thus far, not been confirmed. The theory says spacetime should be warped by primordial gravitational waves that ricocheted out across the Universe with the Big Bang. But while certain types of gravitational waves have been detected, none of these primordial ones have yet been found to support the theory.

    Quantum physics also forces inflation theories into very messy territory. Rare quantum fluctuations are predicted to cause inflation to break space up into an infinite number of patches with wildly different properties – a “multiverse” in which literally every imaginable outcome occurs.

    “The theory is completely indecisive,” says Steinhardt. “It can only say that the observable Universe might be like this or that or any other possibility you can imagine, depending on where we happen to be in the multiverse. Nothing is ruled out that is physically conceivable.”

    Steinhardt, who was one of the original architects of inflationary theory, ultimately got fed up with the lack of predictiveness and untestability.

    “Do we really need to imagine that there exist an infinite number of messy universes that we have never seen and never will see in order to explain the one simple and remarkably smooth Universe we actually observe?” he asks. “I say no. We have to look for a better idea.”

    Rather than being a beginning, the Big Bang could have been a moment of transition from one period of space and time to another – more of a bounce. Credit: Alamy.

    The problem might have to do with the Big Bang itself, and with the idea that there was a beginning to space and time.

    The “Big Bounce” theory agrees with the Big Bang picture of a hot, dense universe 13.8 billion years ago that began to expand and cool. But rather than being the beginning of space and time, that was a moment of transition from an earlier phase during which space was contracting.

    With a bounce rather than a bang, Steinhardt says, distant parts of the cosmos would have plenty of time to interact with each other, and to form a single smooth universe in which the sources of CMB radiation would have had a chance to even out.

    In fact, it’s possible that time has existed forever.

    “And if a bounce happened in our past, why could there not have been many of them?” says Steinhardt. “In that case, it is plausible that there is one in our future. Our expanding universe could start to contract, returning to that dense state and starting the bounce cycle again.”

    Steinhardt and Turok worked together on some early versions of the Big Bounce model, in which the Universe shrunk to such a tiny size that quantum physics took over from classical physics, leaving the predictions uncertain. But more recently, another of Steinhardt’s collaborators, Anna Ijjas, developed a model in which the Universe never gets so small that quantum physics dominates.

    “It’s a rather prosaic, conservative idea described at all times by classical equations,” Steinhardt says. “Inflation says there’s a multiverse, that there’s an infinite number of ways the Universe might come out, and we just happen to live in the one that is smooth and flat. That’s possible but not likely. This Big Bounce model says this is how the Universe must be.”

    Neil Turok has also been exploring another avenue for a simpler alternative to inflationary theory, the “Mirror Universe”. It predicts that another universe dominated by antimatter, but governed by the same physical laws as our own, is expanding outwards on the other side of the Big Bang – a kind of “anti-universe”, if you like.

    “I take one thing away from the observations of the last 30 years, which is that the Universe is unbelievably simple,” he says. “At large scales, it is not chaotic. It is not random. It’s incredibly ordered and regular and requires very few numbers to describe everything.”

    Our forward-time flowing universe could have a perfect reflection that also extends out in reverse from the event we call the Big Bang. Credit: Alamy.

    With this in mind, Turok sees no place for a multiverse, higher dimensions, or new particles to explain what can be seen when we look up at the heavens. The Mirror Universe offers all that – and might also solve one of the Universe’s big mysteries.

    If you add up all the known mass in a galaxy – stars, nebulae, black holes and so on – the total doesn’t create enough gravity to explain the motion within and between galaxies. The remainder seems to be made up of something we cannot currently see – Dark Matter. This mysterious stuff accounts for about 85% of the matter in the universe.

    The Mirror Universe model predicts that the Big Bang produced a particle known as “right-handed neutrinos” in abundance. While particle physicists have yet to directly see any of these particles, they are pretty sure they exist. And it is these that make up dark matter, according to those who support the Mirror Universe theory.

    “It’s the only particle on that list (of particles in the Standard Model) that has the two requisite properties that we haven’t directly observed it yet, and it could be stable,” says Latham Boyle, another leading proponent of the Mirror Universe theory and a colleague of Turok at the Perimeter Institute.

    Perhaps the most challenging alternative to the Big Bang and inflation is Roger Penrose’s “Conformal Cyclic Cosmology” theory (CCC). Like the Big Bounce, it involves a universe that might have existed forever. But in CCC, it never goes through a period of contraction – it only ever expands.

    “The view I have is that the Big Bang was not the beginning,” says Penrose. “The entire picture of what we know nowadays, the whole history of the Universe, is what I call one ‘aeon’ in a succession of aeons.”

    Penrose’s model predicts that much of the matter in the Universe will eventually be dragged into ultra-massive black holes. As the Universe expands and cools to near absolute zero, those black holes will “boil away” through a phenomenon called Hawking Radiation.

    “You have to think in terms of something like a googol years, which means a number one with 100 zeros,” says Penrose. “That’s the number of years or more for the really big ones to finally evaporate away. And then you’ve got a universe really dominated by photons (particles of light).”

    Penrose says at this point, the Universe begins to look much as it did at its start, setting the stage for the start of another aeon.

    Conformal Cyclic Cosmology predicts that much of the Universe will be pulled into enormous black holes that will then boil away. Credit: NASA/JPL-Caltech.

    One of the predictions of CCC is that there might be a record of the previous aeon in the cosmic microwave background radiation that originally inspired the inflation model. When hyper-massive black holes collide, the impact creates a huge release of energy in the form of gravitational waves. When giant black holes finally evaporate, they release a huge amount of energy in the form of low-frequency photons. Both of these phenomena are so powerful, Penrose says, that they can “burst through to the other side” of a transition from one aeon to the next, each leaving its own kind of “signal” embedded in the CMB like an echo from the past.

    Penrose calls the patterns left behind by evaporating black holes “Hawking Points”.

    For the first 380,000 years of the current aeon, these would have been nothing more than tiny points in the cosmos, but as the Universe has expanded, they would appear as “splotches” across the sky.

    Penrose has been working with Polish, Korean and Armenian cosmologists to see if these patterns can actually be found by comparing measurements of the CMB with thousands of random patterns.

    “The conclusion we come to is that we see these spots in the sky with 99.98% confidence,” Penrose says. The physics world has, however, remained largely skeptical of these results to date and there has been limited interest among cosmologists about even attempting to replicate Penrose’s analysis.

    It is unlikely that we will ever be able to directly observe what happened in the first moments after the Big Bang, let alone the moments before. The opaque superheated plasma that existed in the early moments will likely forever obscure our view. But there are other potentially observable phenomena such as primordial gravitational waves, primordial black holes, right-handed neutrinos, that could provide us some clues about which of the theories about our universe are correct.

    “As we develop new theories and new models of cosmology, those will give us other interesting predictions that can that we can look for,” says Mack. “The hope is not necessarily that we’re going to see the beginning more directly, but that maybe through some roundabout way we’ll better understand the structure of physics itself.”

    Until then, the story of our universe, its beginnings and whether it has an end, will continue to be debated.

    See the full article here .


    Please help promote STEM in your local schools.

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  • richardmitnick 6:42 pm on January 2, 2021 Permalink | Reply
    Tags: As the first man-made objects to leave our Solar System the Voyager spacecrafts 1 and 2 are venturing into uncharted territory billions of miles from home. No other spacecraft have travelled as far., Astronomers can only receive Voyager’s information thanks to a massive array of satellite dishes and advanced technology not even existent when the spacecraft were launched., , , , BBC UK, By keeping the interstellar medium at bay the solar wind also keeps out a life-threatening bombardment of radiation and deadly high-energy particles – such as cosmic rays., , , Interstellar space, Kuiper Belt and Oort Cloud, , NASA Voyager 1 and 2-built and launched in 1970s., NASA/IBEX mission, Scientists have been building up a picture of what the interstellar medium is made of thanks largely to observations with radio and X-ray telescopes., The solar wind – a constant powerful stream of charged particles or plasma spraying out in every direction from the Sun.   

    From BBC (UK): “The weird space that lies outside our Solar System” 

    From BBC (UK)

    Credit: NASA/STScI/Aura.

    8th September 2020 [Just now in social media.]
    Patchen Barss

    The mysterious dark vacuum of interstellar space is finally being revealed by two intrepid spacecraft that have become the first human-made objects to leave our Solar System.

    Heliosphere-heliopause showing positions of two Voyager spacecraft. Credit: NASA.

    Far from the protective embrace of the Sun, the edge of our Solar System would seem to be a cold, empty, and dark place. The yawning space between us and the nearest stars was for a long time thought to be a frighteningly vast expanse of nothingness.

    Until recently, it was somewhere that humankind could only peer into from afar. Astronomers paid it only passing attention, preferring instead to focus their telescopes on the glowing masses of our neighbouring stars, galaxies and nebula.

    But two spacecraft, built and launched in 1970s, have for the past few years been beaming back our first glimpses from this strange region we call interstellar space.

    NASA/Voyager 1.

    NASA/Voyager 2.

    As the first man-made objects to leave our Solar System, they are venturing into uncharted territory, billions of miles from home. No other spacecraft have travelled as far.

    And they have revealed that beyond the boundaries of our solar system lies an invisible region of chaotic, frothing activity.

    “When you look at different parts of the electromagnetic spectrum, that area of space is very different from the blackness we perceive with our eyes,” says Michele Bannister, an astronomer at the University of Canterbury in Christchurch, New Zealand, who studies the outer reaches of the Solar System. “Magnetic fields are fighting and pushing and tied up with each other. The image you should have is like the plunge pool under Niagara Falls.”

    Explosions like supernovae fling cosmic rays out in all directions into interstellar space Credit: NASA/ESA Hubble.

    Instead of tumbling water, however, the turbulence is the result of the solar wind – a constant, powerful stream of charged particles, or plasma, spraying out in every direction from the Sun – as it crashes into a cocktail of gas, dust, and cosmic rays that blows between star systems, known as the “interstellar medium”.

    Scientists have been building up a picture of what the interstellar medium is made of over the past century, thanks largely to observations with radio and X-ray telescopes.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    NRAO Karl G Jansky Very Large Array, located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

    ASTRON LOFAR Radio Antenna Bank, Netherlands.

    SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO).

    Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

    NASA Chandra X-ray Space Telescope

    ESA/XMM Newton X-ray telescope (EU).

    NASA/DTU/ASI NuSTAR X-ray telescope.

    They have revealed it is composed of extremely diffuse ionised hydrogen atoms, dust, and cosmic rays interspersed with dense molecular clouds of gas thought to be the birthplace of new stars.

    But its exact nature just outside our solar system has been largely a mystery, principally because the Sun, all eight planets and a distant disc of debris known as the Kuiper Belt, are all contained within a giant protective bubble formed by the solar wind, known as the heliosphere [above]. As the Sun and its surrounding planets hurtle through the galaxy, this bubble buffets against the interstellar medium like an invisible shield, keeping out the majority of harmful cosmic rays and other material.

    Kuiper Belt. Minor Planet Center

    But its life-saving properties also make it more difficult to study what lies beyond the bubble.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase.

    Even determining its size and shape is difficult from within.

    “It’s like you’re inside your home and you want to know what it looks like. You have to go outside and take a look to really tell,” says Elena Provornikova, a postdoctoral researcher at the Johns Hopkins University Applied Physics Laboratory. “The only way to get an idea is to travel far away from the Sun, look back, and take an image from outside the heliosphere.”

    This is no simple task. Compared to the whole of the Milky Way, our Solar System looks smaller than a grain of rice floating in the middle of the Pacific. And yet, the outer edge of the heliosphere is still so distant that it took more than 40 years for the Voyager 1 and Voyager 2 spacecraft [both above] to reach it as they flew from Earth.

    Voyager 1, which took a more direct route through the Solar System, passed out into interstellar space in 2012, before Voyager 2 joined it in 2018. Currently around 13 billion and 11 billion miles from Earth respectively, they are now drifting out, ever further into the space beyond our Solar System, sending back more data as they do.

    The car-sized Voyager spacecraft were launched in 1977 and are now beaming back data from interstellar space. Credit: NASA/JPL-Caltech.

    What these two aging probes revealed about the boundary between the heliosphere and the interstellar medium has provided fresh clues about how our Solar System formed, and how life on Earth is even possible. Far from being a distinct boundary, the very edge of our Solar System actually churns with roiling magnetic fields, clashing stellar windstorms, storms of high energy particles and swirling radiation.

    The size and shape of the heliosphere bubble alters as the Sun’s output changes, and as we pass through different regions of the interstellar medium. When the solar wind rises or falls, it changes the outward pressure on the bubble.

    In 2014, the Sun’s activity surged, sending what amounted to a solar-wind hurricane sweeping out into space. The blast quickly washed over Mercury and Venus at close to 800 km per second (497 miles per second). After two days and 150 million km (93.2 million miles), it enveloped Earth. Fortunately, our planet’s magnetic field [magnetosphere above] shielded us from its powerful, damaging radiation.

    The gust pushed past Mars a day later and carried on through the asteroid belt toward the distant gas giants – Jupiter, Saturn, Uranus and after more than two months, Neptune, which orbits nearly 4.5 billion km (2.8 billion miles) from the Sun.

    After more than six months, the wind finally reached a point more than 13 billion km (8.1 billion miles) from the Sun known as the “termination shock”. Here, the Sun’s magnetic field, which propels the solar wind, becomes weak enough for interstellar medium to push against it.

    The solar wind gust emerged from the termination shock traveling at less than half its previous speed – the hurricane downgraded to a tropical storm. Then in late 2015, it overtook the irregularly shaped form of Voyager 2, which is about the size of a small car. The plasma surge was detected by Voyager’s 40-year-old sensing technologies, powered by a slowly decaying plutonium battery.

    The probe beamed data back toward Earth, which even at the speed of light took 18 hours to reach us. Astronomers could only receive Voyager’s information thanks to a massive array of 70-metre satellite dishes and advanced technology that hadn’t been imagined, let alone invented, when the probe left Earth in 1977.

    NASA Canberra, AU, Deep Space Network. Credit: NASA.

    NASA Deep Space Network dish, Goldstone, CA, USA. Altitude 2,950 ft (900 m). Credit: NASA.

    NASA Deep Space Network Madrid Spain. Credit: NASA.

    The Sun produces a constant barrage of high energy particles known as the solar wind, which can rise and fall with the activity of our star (Credit: NASA)

    The solar wind surge reached Voyager 2 while it was still just inside our Solar System. A little more than a year later, the last gasps of the dying wind reached Voyager 1, which had crossed over into interstellar space in 2012.

    The different routes taken by the two probes meant one was about 30 degrees above the solar plane, the other the same amount below. The solar wind burst reached them in different regions at different times, which provided useful clues about the nature of the heliopause.

    The data revealed that the turbulent boundary is millions of kilometres thick. It covers billions of square kilometres around the surface of the heliosphere.

    The heliosphere is also unexpectedly large, which suggests that the interstellar medium in this part of the galaxy is less dense than people thought. The Sun cuts a path through interstellar space like a boat moving through water, creating a “bow wave” and stretching a wake out behind it, possibly with a tail (or tails) in shapes similar to those of comets. Both Voyagers exited through the “nose” of the heliosphere, and so provided no information about the tail.

    “The estimate from the Voyagers is that the heliopause is about one astronomical unit thick (93 million miles, which is the average distance between the Earth and the Sun),” says Provornikova. “It’s not really a surface. It’s a region with complex processes. And we don’t know what’s going on there.”

    Not only do solar and interstellar winds create a turbulent tug of war in the boundary region, but particles appear to swap charges and momentum. As a result, a portion of the interstellar medium becomes converted to solar wind, actually increasing the outward push of the bubble.

    And while a solar wind surge can provide interesting data, it seems to have a surprisingly small effect on the bubble’s overall size and shape. It appears that what happens outside the heliosphere matters much more than what happens within. The solar wind can wax or wane over time without appearing to dramatically affect the bubble. But if that bubble moves into a region of the galaxy with denser or less dense interstellar wind, then it will shrink or grow.

    But many questions remain unanswered, including those around exactly how typical our protective solar-wind bubble might be.

    The Sun’s heliosphere forms a long tail as it pushes its way through the interstellar medium on its journey around the galaxy. Credit: NASA.

    Provornikova says understanding more about our own heliosphere can tell us more about whether we’re alone in the universe.

    “What we study in our own system will tell us about the conditions for the development of life in other stellar systems,” she says.

    This is largely because by keeping the interstellar medium at bay, the solar wind also keeps out a life-threatening bombardment of radiation and deadly high-energy particles – such as cosmic rays – from deep space.

    Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

    Cosmic rays are protons and atomic nuclei streaming through space at nearly the speed of light. They can be generated when stars explode, when galaxies collapse into black holes, and other cataclysmic cosmic events. The region outside our Solar System is thick with a steady rain of these high-speed subatomic particles, which would be powerful enough to cause deadly radiation poisoning on a less sheltered planet.

    “Voyager definitively said that 90% of this radiation gets filtered out by the Sun,” says Jamie Rankin, a heliophysics researcher at Princeton University, and the first person to write a PhD thesis based on the Voyagers’ interstellar data. “If we didn’t have the solar wind protecting us, I don’t know if we’d be alive.”

    Three additional NASA probes will soon join the Voyagers in interstellar space, although two have already run out of power and stopped returning data. These few tiny pinpricks in the giant boundary will only ever provide limited information on their own. Fortunately, more expansive observation can be done closer to home.

    NASA’s International Boundary Explorer (IBEX), a tiny satellite that has orbited Earth since 2008, detects particles called “energetic neutral atoms” that pass through the interstellar boundary.


    IBEX creates three dimensional maps of the interactions happening all around the edge of the heliosphere.

    The IBEX mission has detected a ribbon of high energy atoms being reflected back from the edge of the heliosphere by the galactic magnetic field (Credit: NASA)

    “You can think of IBEX maps as sort of the ‘Doppler radar’ and the Voyagers as on-the-ground weather stations,” says Rankin. She has used data from Voyagers, IBEX, and other sources to analyse smaller surges in the solar wind, and is currently working on a paper based on the much larger blast that began in 2014. Already, the evidence shows that the heliosphere was shrinking when Voyager 1 passed the boundary, but was expanding again when Voyager 2 crossed over.

    “It’s quite a dynamic boundary,” she says. “It’s pretty amazing that this discovery was captured in IBEX’s 3D maps, which enabled us to track the local responses from the Voyagers at the same time.”

    IBEX has revealed just how dynamic the boundary can be. In its first year it detected a giant ribbon of energetic atoms snaking across the boundary that changed over time, with features appearing and disappearing as briefly as six months. The ribbon turns out to be a region at the nose of the heliosphere where solar wind particles bounce off the galactic magnetc field and are reflected back into the Solar System.

    When Voyager 2 left the solar system it detected a dramatic spike in cosmic rays from which the heliosphere protects us. Credit: NASA/JPL-Caltech/GSFC.

    But there is a twist to the Voyager story. Although they have left the heliosphere, they are still within range of many of our Sun’s other influences. The Sun’s light, for instance, would be visible to the naked human eye from other stars. Our star’s gravity also extends well beyond the heliosphere, holding in place a distant, sparse sphere of ice, dust, and space debris known as the Oort Cloud.

    Voyager 1 crossed over into interstellar space in 2012 100 Astronomical Units from the Sun but it still has the vast Oort Cloud ahead of it. Credit: NASA/JPL-Caltech.

    Oort objects still orbit the Sun, despite floating far out in interstellar space. While some comets have orbits that reach all the way out to the Oort cloud, a region 186-930 billion miles (300-1,500 billion km) is generally considered too distant for us to send probes of our own.

    These distant objects have barely changed since the Solar System began, and may hold keys to everything from how planets form to how likely life is to arise in our universe. And with each wave of new data, new mysteries and questions also emerge.

    Provornikova says there may be a blanket of hydrogen covering some or all of the heliosphere, whose effects have yet to be decoded. In addition, the heliosphere appears to be careening into an interstellar cloud of particles and dust left over from ancient cosmic events whose effects on the boundary – and on those of us who live within it – have not been predicted.

    “It could change the dimensions of the heliosphere, it could change its shape,” says Provornikova. “It could have different temperatures, different magnetic fields, different ionisation and all these different parameters. It’s very exciting because it’s an area of many discoveries, and we know so little about this interaction between our star and the local galaxy.”

    Whatever happens, two car-sized assortments of metal bolted to small parabolic dishes – the intrepid Voyager probes – will be our Solar System’s vanguard, revealing ever more about this strange and uncharted territory as we plough onwards through space.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 6:34 pm on November 30, 2020 Permalink | Reply
    Tags: "One of biology's biggest mysteries 'largely solved' by AI", BBC UK, DeepMind protein studies, , Dr Davis Baker- Baker Lab- U Washington, Predicting how a protein folds into a unique three-dimensional shape has puzzled scientists for half a century.,   

    From BBC (UK): “One of biology’s biggest mysteries ‘largely solved’ by AI” 

    From BBC (UK)

    Helen Briggs

    A DeepMind model of a protein from the Legionnaire’s disease bacteria (Casp-14). Credit: AP.

    One of biology’s biggest mysteries has been solved using artificial intelligence, experts have announced.

    Predicting how a protein folds into a unique three-dimensional shape has puzzled scientists for half a century.

    London-based AI lab, DeepMind, has largely cracked the problem, say the organisers of a scientific challenge.

    A better understanding of protein shapes could play a pivotal role in the development of novel drugs to treat disease.

    The advance by DeepMind is expected to accelerate research into a host of illnesses, including Covid-19.

    Their program determined the shape of proteins at a level of accuracy comparable to expensive and time-consuming lab methods, they say.

    Dr Andriy Kryshtafovych, from University of California (UC), Davis in the US, one of the panel of scientific adjudicators, described the achievement as “truly remarkable”.

    “Being able to investigate the shape of proteins quickly and accurately has the potential to revolutionise life sciences,” he said.

    What are proteins?

    Proteins are present in all living things where they play a central role in the chemical processes essential for life.

    Made up of strings of amino acids, they fold up in an infinite number of ways into elaborate shapes that hold the key to how they carry out their vital functions.

    Getty Images

    Many diseases are linked to the roles of proteins in catalysing chemical reactions (enzymes), fighting disease (antibodies) or acting as chemical messengers (hormones such as insulin).

    “Even tiny rearrangements of these vital molecules can have catastrophic effects on our health, so one of the most efficient ways to understand disease and find new treatments is to study the proteins involved,” said Dr John Moult of the University of Maryland, US, the chair of the panel of scientific adjudicators.

    “There are tens of thousands of human proteins and many billions in other species, including bacteria and viruses, but working out the shape of just one requires expensive equipment and can take years.”

    How does the challenge work?

    In 1972, Christian Anfinsen was awarded a Nobel Prize for his work showing that it should be possible to determine the shape of proteins based on the sequence of their amino acid building blocks.

    Every two years, scores of teams from more than 20 countries blindly attempt to predict using computers the shape of a set of around 100 proteins from their amino acid sequences.

    At the same time, the 3-D structures are worked out in the lab by biologists using traditional techniques like X-ray crystallography and NMR spectroscopy, which determine the location of each atom relative to each other in the protein molecule.

    A team of scientists from CASP (the Community Wide Experiment on the Critical Assessment of Techniques for Protein Structure Prediction) then compares these predictions with 3-D structures solved using experimental methods.

    CASP uses a metric known as the global distance test to assess accuracy, ranging from 0-100. A score of around 90, which DeepMind’s AlphaFold program achieved, is regarded as comparable with lab techniques.

    What happened this year?

    In the latest round of the challenge, Casp-14, AlphaFold determined the shape of around two thirds of the proteins with accuracy comparable to laboratory experiments.

    The assessors said accuracy with most of the other proteins was also high, though not quite at that level.

    AlphaFold is based on a concept called deep learning. In this process, the structure of a folded protein is represented as a spatial graph.

    The program then “learns” using information on the 3-D shapes of known proteins held in the Public Database of Proteins.

    The AI program was able to do in a matter of days what might take years at the laboratory bench.

    How will this information be used?

    Knowing the 3-D structure of a protein is important in drug design and in understanding human diseases, including cancer, dementia and infectious diseases.

    The virus that causes Covid-19 has distinctive spike proteins (in red). Credit: Getty Images.

    One example is Covid-19, where scientists have been studying how the spike protein on the surface of the Sars-CoV-2 virus interacts with receptors in human cells.

    Prof Andrew Martin from University College London (UCL), a former CASP entrant and assessor, told BBC News: “Understanding how a protein sequence folds up into three dimensions is really one of the fundamental questions of biology.

    “The whole way in which a protein functions is dependent on its three-dimensional structure and protein function is relevant to everything in health and disease.

    “By knowing the three-dimensional structures of proteins we can help to design drugs and intervene with health problems whether those be infections or inherited disease.”

    Prof Dame Janet Thornton of EMBL’s European Bioinformatics Institute in Hinxton, UK, said that how proteins fold to create “exquisitely unique three-dimensional structures” is one of biology’s biggest mysteries.

    “A better understanding of protein structures and the ability to predict them using a computer means a better understanding of life, evolution and, of course, human health and disease,” she explained.

    What happens next?

    Other scientists will want to look at the data to determine how accurate the AI method is and how well it performs at a very detailed level.

    There’s still a knowledge gap, including working out how multiple proteins fit together and how proteins interact with other molecules, such as DNA and RNA.

    “Now that the problem has been largely solved for single proteins, the way is open for development of new methods for determining the shape of protein complexes – collections of proteins that work together to form much of the machinery of life, and for other applications,” said Dr Kryshtafovych.

    Sorry, I have to insert here Dr David Baker, U Washington (US) and the Baker Lab’s rosetta@home, a project running on BOINC software [Berkeley Open Infrastructure for Network Computing] from UC Berkeley’s Space Science Laboratory. Baker’s project has been successfully synthesizing proteins for years.

    U Washington,Dr. David Baker, Baker Lab.

    David Baker’s Rosetta@home project, a project running on BOINC software from UC Berkeley

    This is not to take anything away from the success of DeepMind which is addressing negative actions in DNA.

    I was a BOINC cruncher for quite some time, winding up with almost 37 million credits, still in the 99th percentile for all of BOINC of all time when I finally had to quit because of my own problems.

    My BOINC

    See the full article here .


    Please help promote STEM in your local schools.

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  • richardmitnick 3:15 pm on November 28, 2020 Permalink | Reply
    Tags: "Polar scientists wary of impending satellite gap", American IceSat-2 mission, BBC UK, ESA/NASA Sentinel-6 Michael Freilich, European CryoSat-2, NASA IceBridge mission, , Why is Thwaites Glacier so important?   

    From BBC (UK): “Polar scientists wary of impending satellite gap” 

    From BBC (UK)

    Jonathan Amos

    It’s satellites that have tracked the loss of ice in the Antarctic and the Arctic. Credit: Rob Larter/BAS.

    There is going to be a gap of several years in our ability to measure the thickness of ice at the top and bottom of the world, scientists are warning.

    The only two satellites dedicated to observing the poles are almost certain to die before replacements are flown.

    This could leave us blind to some important changes in the Arctic and the Antarctic as the climate warms.

    The researchers have raised their concerns with the European Commission and the European Space Agency.

    A letter detailing the problem – and possible solutions – was sent to leading EC and ESA officials this week; and although the US space agency (NASA) has not formally been addressed, it has been made aware of the correspondence.

    Dog kennel’ satellite blasts off on ocean mission

    ESA/NASA Sentinel-6 Michael Freilich

    New Sentinels to check the pulse of Earth

    Greenland and Antarctica ice loss accelerating

    At issue is the longevity of the European CryoSat-2 and American IceSat-2 missions.

    ESA/CryoSat 2

    NASA ICESat 2 lauched in 2018

    These spacecraft carry instruments called altimeters that gauge the shape and elevation of ice surfaces.

    They’ve been critical in recording the loss of sea-ice volume and the declining mass of glaciers.

    What’s unique about the satellites is their orbits around the Earth. They fly to 88 degrees North and South from the equator, which means they see the entire Arctic and Antarctic regions, bar a small circle about 430km in diameter at the poles themselves.

    In contrast, most other satellites don’t usually go above 83 degrees. As a consequence, they miss, for example, a great swathe of the central Arctic Ocean and its frozen floes.

    The worry is that CryoSat-2 and IceSat-2 will have been decommissioned long before any follow-ups get launched.

    CryoSat-2 is already way beyond its design life. It was put in space in 2010 with the expectation it would work for at least 3.5 years. Engineers think they can keep it operating until perhaps 2024, but battery degradation and a fuel leak suggest not for much longer.

    IceSat-2 was launched in 2018 with a design life of three years, but with the hope – and expectation – it can operate productively deep into the decade (see footnote).

    The satellites’ orbits leave only a very small hole in their measurements at the poles. Credit: ESA.

    “Without successful mitigation, there will be a gap of between two and five years in our polar satellite altimetry capability,” the scientists’ letter states. “This gap will introduce a decisive break in the long-term records of ice sheet and sea-ice thickness change and polar oceanography and this, in turn, will degrade our capacity to assess and improve climate model projections.”

    The only satellite replacement currently in prospect is the EC/Esa mission codenamed Cristal. It will be like Cryosat, although with much greater capability thanks to a dual-frequency radar altimeter.

    Industry has started work on the spacecraft but it won’t launch until 2027/28, maybe even later because full funding to make this date a reality is not yet in place.

    Dr Josef Aschbacher, the director of Earth observation at ESA, said his agency was working as fast as it could to plug the gap.

    “This is a concern; we recognise it,” he told the BBC. “We’ve put plans in motion to build Cristal as quick as we can. Despite Covid, despite heavy workloads and video conferences by everyone – we have gone through the evaluation… and Cristal was kicked off in early September.”

    An option for Europe? NASA IceBridge mission.The Americans flew a stop-gap laser altimeter on aeroplanes. Credit: NASA.

    Just over 10% of the near-600 signatories to the letter are American scientists.

    Dr Thomas Zurbuchen, the head of science at NASA, is not being sent the letter because it is primarily aimed at European funders – and most of the signatories are European. Nonetheless, Dr Zurbuchen is aware of the letter and its contents.

    He said he was hopeful any polar gap could be plugged or minimised.

    “I think there are multiple options at this moment in time that we can deploy to that end, in partnership or otherwise,” he commented.

    Arctic sea-ice shrinks to near record low extent
    ‘The sea-ice is dying’: Historic Arctic trip ends
    German ship completes historic Arctic expedition
    RV Polarstern returns to the port city Bremerhaven early on Monday. Credit: Annika Meyer.
    ‘Doomsday Glacier’ vulnerability seen in new maps

    Why is Thwaites Glacier so important?

    Flowing off the west of the Antarctic continent, Thwaites is almost as big as Great Britain.

    It’s a majestic sight, with its buoyant front, or “ice shelf”, pushing far out to sea and kicking off huge icebergs. But satellite monitoring indicates this glacier is melting at an accelerating rate.

    In the 1990s it was losing just over 10 billion tonnes of ice a year. Today, it’s more like 80 billion tonnes. The cause of the melting is thought to be the influx of relatively warm bottom-water drawn in from the wider ocean.

    Currently, Thwaites’ ice loss contributes approximately 4% to the annual rise in global sea-levels, with the potential to add 65cm in total should the whole glacier collapse.

    No-one thinks this will happen in the short-to-medium term, but Thwaites is considered particularly vulnerable in a warming world, and scientists would like to know precisely how fast any changes might occur.

    One of those solutions in Europe would be to run a version of Nasa’s IceBridge project.

    NASA IceBridge, an airborne platform that the US agency operated in the eight years between the end of the very first IceSat mission in 2010 and the launch of IceSat-2 in 2018 [above].

    An aeroplane flew a laser altimeter over the Arctic and the Antarctic to gather some limited data-sets that could eventually be used to tie the two IceSat missions together.

    There are many who think a European “CryoBridge” is the most affordable and near-term option to mitigate the empty years between CryoSat-2 and Cristal.

    ESA/Airbus Copernicus Polar Ice and Snow Topography Altimeter CRISTAL Mission depiction.

    The cost of manufacture of the airborne radar altimeter could be accomplished for perhaps €5m (£4.5m), scientists believe, but its design and fabrication would likely take two years. Such a project would therefore have to get under way relatively soon. It would, of course, also need an operational budget.

    The signatories to the letter sent to the EC and ESA include leading scientists using CryoSat and IceSat data, the president of the International Glaciology Society, and lead authors on the United Nations’ Intergovernmental Panel on Climate Change, which prepares the authoritative state-of-the-climate reports for world governments.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 1:38 pm on October 12, 2020 Permalink | Reply
    Tags: "German ship completes historic Arctic expedition", BBC UK, Disappearence of Arctic Polar ice., , R/V Polarstern DE   

    From BBC UK: “German ship completes historic Arctic expedition” 

    From BBC UK

    Jonathan Amos

    R/V Polarstern DE

    The German R/V Polarstern has sailed back into its home port after completing a remarkable expedition to the Arctic Ocean.

    The ship spent a year in the polar north, much of it with its engines turned off so it could simply drift in the sea-ice.

    The point was to study the Arctic climate and how it is changing.

    And expedition leader, Prof Markus Rex, returned with a warning. “The sea-ice is dying,” he said.

    “The region is at risk. We were able to witness how the ice disappears and in areas where there should have been ice that was many metres thick, and even at the North Pole – that ice was gone,” the Alfred Wegener Institute scientist told a media conference in Bremerhaven on Monday.

    Arctic sea-ice shrinks to near record low extent
    Warmth shatters section of Greenland ice shelf
    Europe and US line up to measure Antarctic sea-ice

    Mid-winter in the Arctic is accompanied by 24-hour darkness. Credit: Stefan Hendricks.

    R/V Polarstern was on station to document this summer’s floes shrink to their second lowest ever extent in the modern era.

    The floating ice withdrew to just under 3.74 million sq km (1.44 million sq miles). The only time this minimum has been beaten in the age of satellites was 2012, when the pack ice was reduced to 3.41 million sq km.

    The downward trend is about 13% per decade, averaged across the month of September.

    “This reflects the warming of the Arctic,” said Prof Rex. “The ice is disappearing and if in a few decades we have an ice-free Arctic – this will have a major impact on the climate around the world.”

    On occasions the expedition was harassed by polar bears. Credit: Esther Horvath.

    The €130m (£120m/$150m) cruise set off from Tromsø, Norway, on 20 September last year. The project was named the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC).

    The idea was to recreate the historic voyage of Norwegian polar researcher Fridtjof Nansen, who undertook the first ice drift through the Arctic Ocean more than 125 years ago.

    R/V Polarstern embedded itself in the ice on the Siberian side of the Arctic basin with the intention of floating across the top of the world and emerging from the floes just east of Greenland.

    In the course of this drift, hundreds of researchers came aboard to study the region’s environment.

    They deployed a battery of instruments to try to understand precisely how the ocean and atmosphere are responding to the warming forced on the Arctic by the global increase in greenhouse gases.

    Investigations were conducted to improve future measurements made from space. Credit: MOSAIC/AWI.

    Coronavirus only briefly interrupted the expedition – not by making participants ill, but by obliging the ship at one point to leave the floes to go pick up its next rotation of scientists. Other ships and planes were supposed to deliver the participants direct to R/V Polarstern, but international movement restrictions made this extremely challenging in the early-to-middle part of this year.

    Despite the hiatus, Prof Rex declared the MOSAiC project a huge success.

    The mass of data and samples now in the possession of researchers would make the modelling they use to project future climate change much more robust, he explained.

    It was as if the MOSAiC scientists had been shown the inner workings of an intricate clock, he said.

    “We looked at all the different elements, down to the different screws of this Arctic system. And now we understand the entire clockwork better than ever before. And maybe we can rebuild this Arctic system on a computer model,” he told reporters.

    Prof Rex said the sea-ice was very thin or even absent in places where it used to be thick. Credit: Steffen Graupner.


    See the full article here .


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