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  • richardmitnick 1:07 pm on November 16, 2021 Permalink | Reply
    Tags: "Black holes may be growing as the universe expands", , , , , Live Science (US)   

    From Live Science (US) : “Black holes may be growing as the universe expands” 

    From Live Science (US)

    Ben Turner

    A new hypothesis suggests the universe’s expansion could be causing all material objects to grow in mass.

    An artist’s depiction of the IC 10 X-1 system, a black hole lurks in the upper left corner. (Image credit: Universal History Archive/Universal Images Group via Getty Images)

    The universe’s black holes are bigger than astrophysicists expected them to be. Now, a new study suggests why: Every single black hole may be growing as the universe expands.

    The new hypothesis, called “cosmological coupling,” argues that as the universe expands outward after the Big Bang, all objects with mass grow with it too. And black holes, as some of the most massive objects to exist, grow the most.

    This hypothesis stems from the gravitational ripples in space-time that occur when two massive black holes get locked in orbit, spiral inward and collide. Since 2015, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo interferometer, which are designed to detect these gravitational waves, have observed many of these black hole mergers.

    Caltech /MIT Advanced aLigo

    But the waves contain a mystery. Based on the estimated size distribution of stars in the universe, black holes should have masses less than roughly 40 times the mass of the sun. But data taken from these gravitational waves show that many black holes are more than 50 solar masses, and some approach 100 solar masses.

    A common explanation for this mismatch is that black holes grow over time by gorging on gas, dust, stars and even other black holes. But because black holes often form after giant stellar explosions called supernovas, many black holes emerge in regions of space without any of this material. Astronomers have suggested alternative explanations, but all propose unseen changes to scientists’ current understanding of star life cycles. And none can explain the staggering size diversity of merged black holes that gravitational wave observatories have detected.

    The new paper, published Nov. 3 in The Astrophysical Journal Letters [no working links], proposes an explanation of both the large and small merged black hole masses: The ballooning masses of the black holes aren’t a result of anything they’re eating but are instead somehow tethered to the expansion of the universe itself.

    This would mean that all of the universe’s black holes — including the merging black holes detected in gravitational wave experiments, the wandering black holes at the outskirts of our galaxy and even the enormous supermassive black holes at the centers of most galaxies — are growing over time.

    To investigate their hypothesis, the researchers chose to model two merging black in a growing universe, rather than the static universes other research teams build for the sake of simplifying the complex equations (derived from Einstein’s theory of general relativity) that provide the foundations for black hole merger models.

    It takes just a few seconds for two spiraling black holes to merge, so assuming a static universe over that short time frame, as past work has done, seems sensible.

    Artist’s by now iconic conception of two merging black holes similar to those detected by LIGO. Credit: Aurore Simonnet /Caltech MIT Advanced aLIGO(US)/Sonoma State University (US).

    But the researchers disagree, they say that if scientists assume a static universe in their models, they could be ruling out potential changes to the two black holes over the billions of years they existed before reaching the point of collision

    “It’s an assumption that simplifies Einstein’s equations, because a universe that doesn’t grow has much less to keep track of,” study first author Kevin S. Croker, a professor in The University of Hawaii at Mānoa (US) Department of Physics and Astronomy, said in the statement. “There is a trade-off, though: Predictions may only be reasonable for a limited amount of time.”

    By simulating millions of pairs of stars — from their births to their deaths — the researchers were able to study the ones which died to form paired black holes and link how much they grew in proportion to the universe’s expansion. After comparing some predictions made by the model universe they had grown with LIGO-Virgo data, the researchers were surprised to see they matched well.

    “I have to say, I didn’t know what to think at first,” co-author Gregory Tarlé, a professor of physics at The University of Michigan (US), said in a statement. “It was such a simple idea, I was surprised it worked so well.”

    The hypothesis may sound outlandish, but cosmological coupling exists elsewhere in astrophysics. The most famous example of this is probably “red shift,” in which objects moving away have their light stretched to longer (and, therefore, redder) wavelengths.

    This means that as the universe expands and stars move away from each other — like dots drawn on an inflating balloon — the light particles, or photons, that the stars emit become redder over time, losing energy as they do so. The energy of light is said to be cosmologically coupled with the universe’s expansion.

    If the researchers are correct, it means everything with mass is getting bigger — suns, neutron stars, planets and even humans. Of course, this coupling would be much weaker for us than for black holes.

    “Cosmological coupling does apply to other objects and material in the universe, but the strength of the coupling is so weak that you cannot see its effects,” Croker told Live Science. “For the types of black hole we have hypothesized, the coupling can be a million times larger than what you’d expect from the core of the sun. And even for these sorts of black holes, you might have to wait hundreds of millions of years to just double your mass.”

    It may just be an interesting idea for now, but as gravitational wave detectors become more sensitive over time, more and more data will become available to test the hypothesis, Croker said.

    “Planned upgrades to LIGO-Virgo, plus the data they will collect over the next decade, will describe many more black hole mergers,” Croker said. “The more data that is collected, the more powerfully we can test our hypothesis. Space-based gravity wave experiments, like LISA [the Laser Interferometer Space Antenna], may allow us to see the mass gain directly in single systems.”

    Gravity is talking. Lisa will listen. Dialogos of Eide.

    European Space Agency(EU)/National Aeronautics and Space Administration (US) eLISA space based, the future of gravitational wave research.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 12:55 pm on October 13, 2021 Permalink | Reply
    Tags: "Scientists capture image of bizarre 'electron ice' for the first time", , Live Science (US), , Wigner crystal — a strange honeycomb-pattern material inside another material made entirely out of electrons.   

    From Live Science (US) : “Scientists capture image of bizarre ‘electron ice’ for the first time” 

    From Live Science (US)

    Ben Turner

    The scanning tunnelling image of the graphene sheet shows the honeycomb imprint of the ‘electron ice’ underneath it. (Image credit: H. Li et al./Nature)

    Physicists have taken the first ever image of a Wigner crystal — a strange honeycomb-pattern material inside another material made entirely out of electrons.

    Hungarian physicist Eugene Wigner first theorized this crystal in 1934, but it’s taken more than eight decades for scientists to finally get a direct look at the “electron ice.” The fascinating first image shows electrons squished together into a tight, repeating pattern — like tiny blue butterfly wings, or pressings of an alien clover.

    The researchers behind the study, published on Sept. 29 in the journal Nature, say that while this isn’t the first time that a Wigner crystal has been plausibly created or even had its properties studied, the visual evidence they collected is the most emphatic proof of the material’s existence yet.

    “If you say you have an electron crystal, show me the crystal,” study co-author Feng Wang, a physicist at The University of California (US), told Nature News.

    Inside ordinary conductors like silver or copper, or semiconductors like silicon, electrons zip around so fast that they are barely able to interact with each other. But at very low temperatures, they slow down to a crawl, and the repulsion between the negatively charged electrons begins to dominate. The once highly mobile particles grind to a halt, arranging themselves into a repeating, honeycomb-like pattern to minimize their total energy use.

    To see this in action, the researchers trapped electrons in the gap between atom-thick layers of two tungsten semiconductors — one tungsten disulfide and the other tungsten diselenide. Then, after applying an electric field across the gap to remove any potentially disruptive excess electrons, the researchers chilled their electron sandwich down to 5 degrees above absolute zero. Sure enough, the once-speedy electrons stopped, settling into the repeating structure of a Wigner crystal.

    The researchers then used a device called a scanning tunneling microscope (STM) to view this new crystal. STMs work by applying a tiny voltage across a very sharp metal tip before running it just above a material, causing electrons to leap down to the material’s surface from the tip. The rate that electrons jump from the tip depends on what’s underneath them, so researchers can build up a picture of the Braille-like contours of a 2D surface by measuring current flowing into the surface at each point.

    But the current provided by the STM was at first too much for the delicate electron ice, “melting” it upon contact. To stop this, the researchers inserted a single-atom layer of graphene just above the Wigner crystal, enabling the crystal to interact with the graphene and leave an impression on it that the STM could safely read — much like a photocopier. By tracing the image imprinted on the graphene sheet completely, the STM captured the first snapshot of the Wigner crystal, proving its existence beyond all doubt.

    Now that they have conclusive proof that Wigner crystals exist, scientists can use the crystals to answer deeper questions about how multiple electrons interact with each other, such as why the crystals arrange themselves in honeycomb orderings, and how they “melt.” The answers will offer a rare glimpse into some of the most elusive properties of the tiny particles.

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 11:59 am on October 1, 2021 Permalink | Reply
    Tags: "Lava eruption at Kilauea spews 'Pele's hair' volcanic glass into Hawaii's skies", , Live Science (US),   

    From Live Science (US) : “Lava eruption at Kilauea spews ‘Pele’s hair’ volcanic glass into Hawaii’s skies” 

    From Live Science (US)

    Laura Geggel

    Pilots flying by the volcano reported seeing “Pele’s hair.”

    The Kilauea eruption, as seen at dawn local time on Sept. 30. Lava fountains are spurting out at multiple fissure locations at the base and west wall of the crater, and a lava lake is growing within Halema’uma’u. (Image credit: B. Carr/

    Kilauea volcano is erupting, sending lava and thread-like pieces of volcanic glass, known as Pele’s hair, into Hawaii’s skies, according to the U.S. Geological Survey (USGS) and the National Weather Service.

    The eruption began at about 3:20 p.m. local Hawaii time Wednesday (Sept. 29), when the USGS Hawaiian Volcano Observatory detected a glow from its webcam at Kilauea summit. That glow indicated a lava eruption happening at Halema’uma’u crater — a pit crater nestled in the much larger Kilauea caldera, or crater.

    The webcam footage also revealed fissures at the base of Halema’uma’u crater that were releasing lava flows onto the surface of the lava lake that had been active until May 2021, the USGS said in a statement. However, the eruption at Kilauea — located within Hawaii Volcanoes National Park, on Hawaii’s Big Island — is confined to Halema’uma’u crater, meaning it’s not currently a threat to the public.

    “At this time, we don’t believe anybody or any residents are in danger, but we do want to remind folks the park remains open,” Cyrus Johnasen, a Hawaii County spokesperson, told Hawaii news station KHON2 on Sept. 29. “It will remain open until the evening. Please proceed with caution,” especially for those with respiratory conditions, he added.

    However, the part of the park where the eruption is happening is currently closed to the public, according to the USGS.

    A low lava fountain near the center of the growing Halema’uma’u lava lake. (Image credit: M. Patrick/USGS)

    Due to the eruption, the Hawaiian Volcano Observatory has elevated Kilauea’s volcano alert level from “watch” to “warning” and its aviation color code from orange to red, which warns pilots about possible ash emissions. Those are the highest warning levels, meaning a “major volcanic eruption is imminent, underway or suspected, with hazardous activity both on the ground and in the air,” according to the USGS.

    The eruption within Halema’uma’u crater is spewing low lava fountains in the center of the lava lake (pictured) and along the western wall of Halema’uma’u. (Image credit: M. Patrick/USGS)

    Meanwhile, several pilots flying aircraft near Kilauea Wednesday evening reported seeing volcanic glass known as Pele’s hair, according to the National Weather Service. The golden, sharp strands of glass — named for Pele, the Hawaiian goddess of fire and volcanoes — form when gas bubbles within lava burst at the surface.

    “The skin of the bursting bubbles flies out, and some of the skin becomes stretched into these very long threads, sometime[s] as long as a couple of feet [more than half a meter] or so,” Don Swanson, a research geologist at the Hawaiian Volcano Observatory, previously told Live Science.

    Pele’s hair can be beautiful, but it poses a danger if it’s ingested through drinking water, Swanson cautioned.

    The current eruption is the latest of a long string of volcanic activity at Kilauea. At an elevation of 4,009 feet (1,222 m) aboveground, the shield-shaped volcano has a magma-pumping system that extends more than 37 miles (60 kilometers) below Earth, according to the USGS. Kilauea has erupted 34 times since 1952, and it erupted almost continuously from 1983 to 2018 along its East Rift Zone. A vent at Halema’uma’u crater was home to an active lava pond and a vigorous gas plume from 2008 to 2018.

    Kilauea’s volcanic activity also made headlines in May 2018, when the lava lake at the summit caldera drained just as the Eastern Rift Zone revved to life with lava fountains and new fissures, whose lava created a red-hot river that destroyed hundreds of houses before draining into the ocean.

    From December 2020 to May 2021, a summit eruption made a lava lake within Halema’uma’u crater, and in August 2021, a series of small earthquakes rattled the summit.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 8:31 am on September 6, 2021 Permalink | Reply
    Tags: "An 'Internet apocalypse' could ride to Earth with the next solar storm new research warns", , Geomagnetics, Live Science (US),   

    From Live Science (US): “An ‘Internet apocalypse’ could ride to Earth with the next solar storm, new research warns” 

    From Live Science (US)

    Brandon Specktor

    The underwater cables that connect nations could go offline for months, the study warns.

    The sun is always showering Earth with a mist of magnetized particles known as solar wind. For the most part, our planet’s magnetic shield blocks this electric wind from doing any real damage to Earth or its inhabitants, instead sending those particles skittering toward the poles and leaving behind a pleasant aurora in their wake.

    But sometimes, every century or so, that wind escalates into a full-blown solar storm — and, as new research presented at the SIGCOMM 2021 data communication conference warns, the results of such extreme space weather could be catastrophic to our modern way of life.

    In short, a severe solar storm could plunge the world into an “internet apocalypse” that keeps large swaths of society offline for weeks or months at a time, Sangeetha Abdu Jyothi, an assistant professor at The University of California-Irvine (US), wrote in the new research paper. (The paper has yet to appear in a peer-reviewed journal).

    “What really got me thinking about this is that with the pandemic we saw how unprepared the world was. There was no protocol to deal with it effectively, and it’s the same with internet resilience,” Abdu Jyothi told WIRED. “Our infrastructure is not prepared for a large-scale solar event.”

    Part of the problem is that extreme solar storms (also called coronal mass ejections) are relatively rare; scientists estimate the probability of an extreme space weather directly impacting Earth to be between 1.6% to 12% per decade, according to Abdu Jyothi’s paper.

    In recent history, only two such storms have been recorded — one in 1859 and the other in 1921. The earlier incident, known as the Carrington Event, created such a severe geomagnetic disturbance on Earth that telegraph wires burst into flame, and auroras — usually only visible near the planet’s poles — were spotted near equatorial Colombia. Smaller storms can also pack a punch; one in March 1989 blacked out the entire Canadian province of Quebec for nine hours.

    Since then, human civilization has become much more reliant on the global internet, and the potential impacts of a massive geomagnetic storm on that new infrastructure remain largely unstudied, Abdu Jyothi said. In her new paper, she tried to pinpoint the greatest vulnerabilities in that infrastructure.

    The good news is, local and regional internet connections are likely at low risk of being damaged because fiber-optic cables themselves aren’t affected by geomagnetically induced currents, according to the paper.

    However, the long undersea internet cables that connect continents are a different story. These cables are equipped with repeaters to boost the optical signal, spaced at intervals of roughly 30 to 90 miles (50 to 150 kilometers). These repeaters are vulnerable to geomagnetic currents, and entire cables could be made useless if even one repeater goes offline, according to the paper.

    If enough undersea cables fail in a particular region, then entire continents could be cut off from one another, Abdu Jyothi wrote. What’s more, nations at high latitudes — such as the U.S. and the U.K. — are far more susceptible to solar weather than nations at lower latitudes. In the event of a catastrophic geomagnetic storm, it’s those high-latitude nations that are most likely to be cut off from the network first. It’s hard to predict how long it would take to repair underwater infrastructure, but Abdu Jyothi suggests that large-scale internet outages that last weeks or months are possible.

    In the meantime, millions of people could lose their livelihoods.

    “The economic impact of an Internet disruption for a day in the US is estimated to be over $7 billion,” Abdu Jyothi wrote in her paper. “What if the network remains non-functional for days or even months?”

    If we don’t want to find out, then grid operators need to start taking the threat of extreme solar weather seriously as global internet infrastructure inevitably expands. Laying more cables at lower latitudes is a good start, Abdu Jyothi said, as is developing resilience tests that focus on the effects of large-scale network failures.

    When the next big solar storm does blast out of our star, people on Earth will have about 13 hours to prepare for its arrival, she added. Let’s hope we’re ready to make the most of that time when it inevitably arrives.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 2:16 pm on August 28, 2021 Permalink | Reply
    Tags: "Earthquake swarm rocks the ground at Hawai'i's Kilauea volcano", , , , , Live Science (US),   

    From Live Science (US): “Earthquake swarm rocks the ground at Hawaii’s Kilauea volcano” 

    From Live Science (US)

    Harry Baker

    A lava lake inside the Pu’u ‘Ō’ō crater in Kilauea’s’ eastern rift zone during a previous eruption. (Image credit: Shutterstock)

    Kilauea volcano gave scientists and local Hawaiians a scare this week, when a swarm of more than 140 earthquakes in just 12 hours prompted authorities to raise the alarm over a possible imminent eruption.

    But now, Kilauea’s brief rumble is over; the volcano did not erupt and is barely registering any earthquakes.

    The Geological Survey (US) made this report on Thursday (Aug. 26).

    However, Kilauea’s flare of activity set scientists on edge. The earthquake swarm occurred between 4:30 p.m. local time (10:30 p.m. EDT) Monday (Aug. 23) and 4:30 a.m. local time (10:30 a.m. EDT) Tuesday (Aug. 24) beneath the south part of Kilauea’s summit caldera, with a peak in activity around 1:30 a.m. local time (7:30 a.m. EDT) Wednesday.

    This is according to the USGS.

    The earthquakes were tiny; most registered at below magnitude 1.0, with the most violent reaching magnitude 3.3. The tectonic activity also coincided with a shift in the ground formation to the west of the swarm, which the USGS said “may indicate an intrusion of magma occurring about 0.6 to 1.2 miles (1 to 2 kilometers) beneath the south caldera.”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

  • richardmitnick 10:23 am on August 10, 2021 Permalink | Reply
    Tags: "Origin of dinosaur-ending asteroid possibly found. And it's dark", , Live Science (US), The impact was caused by a giant dark primitive asteroid from the outer reaches of the solar system's main asteroid belt.   

    From Live Science (US) : “Origin of dinosaur-ending asteroid possibly found. And it’s dark” 

    From Live Science (US)

    Mara Johnson-Groh

    A giant asteroid collided with Earth on the Yucatan Peninsula some 66 million years ago, as shown in this illustration. Credit: MARK GARLICK/SCIENCE PHOTO LIBRARY via Getty Images)

    About 66 million years ago, an estimated 6-mile-wide (9.6 kilometers) object slammed into Earth, triggering a cataclysmic series of events that resulted in the demise of non-avian dinosaurs.

    Now, scientists think they know where that object came from.

    According to new research, the impact was caused by a giant dark primitive asteroid from the outer reaches of the solar system’s main asteroid belt, situated between Mars and Jupiter.

    This region is home to many dark asteroids — space rocks with a chemical makeup that makes them appear darker (reflecting very little light) compared with other types of asteroids.

    “I had a suspicion that the outer half of the asteroid belt — that’s where the dark primitive
    asteroids are — may be an important source of terrestrial impactors,” said David Nesvorný, a researcher from the Southwest Research Institute (US) in Colorado, who led the new study. “But I did not expect that the results [would] be so definitive,” adding that this might not be true for smaller impactors.

    Clues about the object that ended the reign of non-avian dinosaurs have previously been found buried in the Chicxulub crater, a 90-mile-wide (145 km) circular scar in Mexico’s Yucatan Peninsula left by the object’s collision.

    Geochemical analysis of the crater has suggested that the impacting object was part of a class of carbonaceous chondrites — a primitive group of meteorites that have a relatively high ratio of carbon and were likely made very early on in the solar system’s history.

    Based on this knowledge, scientists have previously tried to pinpoint the impactor’s origin, but many theories have crumbled over time. Researchers have previously suggested the impactor came from a family of asteroids from the inner part of the main asteroid belt, but follow-up observations of those asteroids found they didn’t have the right composition. Another study, this one published in February in the journal Scientific Reports, suggested the impact was caused by a long-period comet, Live Science reported. But that research has since come under criticism, according to a June paper published in the journal Astronomy & Geophysics.

    In the new study, published in the November 2021 issue of the journal Icarus, researchers developed a computer model to see how often main belt asteroids escape toward Earth and if such escapees could be responsible for the dinosaur-ending crash.

    Simulating over hundreds of millions of years, the model showed thermal forces and gravitational tugs from planets periodically slingshotting large asteroids out of the belt. On average, an asteroid more than 6 miles wide from the outer edge of the belt was flung into a collision course with Earth once every 250 million years, the researchers found. This calculation makes such an event five times more common than previously thought and consistent with the Chicxulub crater created just 66 million years ago, which is the only known impact crater thought to have been produced by such a large asteroid in the last 250 million years. Furthermore, the model looked at the distribution of “dark” and “light” impactors in the asteroid belt and showed half of the expelled asteroids were the dark carbonaceous chondrites, which matches the type thought to have caused Chicxulub crater.

    “This is just an excellent paper,” said Jessica Noviello, NASA fellow in the postdoctoral management program at the Universities Space Research Association at Goddard Space Flight Center, who was not involved with the new research. “I think they make a good argument for why [the Chicxulub impactor] could have come from that part of the solar system.”

    In addition to possibly explaining the origin of the Chicxulub crater impactor, the findings also help scientists understand the origins of other asteroids that have struck Earth further in the past. Neither of the other two largest impact craters on Earth, the Vredefort crater in South Africa and the Sudbury Basin in Canada, have known impactor origins. The results could also help scientists predict where future large impactors might originate..

    “We find in the study that some 60% of large terrestrial impactors come from the outer half of the asteroid belt … and most asteroids in that zone are dark/primitive,” Nesvorný told Live Science. “So there is a 60% — 3 in 5 — probability that the next one will come from the same region.”

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

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