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  • richardmitnick 5:22 pm on November 25, 2022 Permalink | Reply
    Tags: "Here’s why some supermassive black holes blaze so brightly", Astronomers saw a telltale signature of shock waves shooting along a jet., , , , , , , IXPE, Science News,   

    From IXPE At The National Aeronautics and Space Administration Via “Science News” : “Here’s why some supermassive black holes blaze so brightly” 

    From IXPE

    At

    The National Aeronautics and Space Administration

    Via

    Science News

    11.23.22
    https://www.sciencenews.org/author/lisa-grossman

    Astronomers saw a telltale signature of shock waves shooting along a jet.

    1

    Blazars (one illustrated) are active black holes that shoot jets of charged particles into space. New work shows how order and chaos in those jets can launch the particles. Credit: NASA JPL-Caltech.

    For the first time, astronomers have observed how certain supermassive black holes launch jets of high-energy particles into space — and the process is shocking.

    Shock waves propagating along the jet of one such blazar contort magnetic fields that accelerate escaping particles to nearly the speed of light, astronomers report November 23 in Nature [below]. Studying such extreme acceleration can help probe fundamental physics questions that can’t be studied any other way.

    Blazars are active black holes that shoot jets of high-energy particles toward Earth, making them appear as bright spots from millions or even billions of light-years away (SN: 7/14/15). Astronomers knew that the jets’ extreme speeds and tight columnated beams had something to do with the shape of magnetic fields around black holes, but the details were fuzzy.

    Enter the Imaging X-Ray Polarimetry Explorer, or IXPE, an orbiting telescope launched in December 2021. Its mission is to measure X-ray polarization, or how X-ray light is oriented as it travels through space. While previous blazar observations of polarized radio waves and optical light probed parts of jets days to years after they’d been accelerated, polarized X-rays can see into a blazar’s active core (SN: 3/24/21).

    “In X-rays, you’re really looking at the heart of the particle acceleration,” says astrophysicist Yannis Liodakis of the University of Turku in Finland. “You’re really looking at the region where everything happens.”

    In March 2022, IPXE looked at an especially bright blazar called Markarian 501, located about 450 million light-years from Earth.

    Liodakis and colleagues had two main ideas for how magnetic fields might accelerate Markarian 501’s jet. Particles could be boosted by magnetic reconnection, where magnetic field lines break, reform and connect with other nearby lines. The same process accelerates plasma on the sun (SN: 11/14/19). If that was the particle acceleration engine, the polarization of light should be the same along the jet in all wavelengths, from radio waves to X-rays.

    Another option is a shock wave shooting particles down the jet. At the site of the shock, the magnetic fields suddenly switch from turbulent to ordered. That switch could send particles zooming away, like water through the nozzle of a hose. As the particles leave the shock site, turbulence should take over again. If a shock was responsible for the acceleration, short wavelength X-rays should be more polarized than longer wavelength optical and radio light, as measured by other telescopes.

    2
    The IXPE spacecraft (illustrated) observed polarized X-rays come from a blazar and its jet. The inset illustrates how particles in the jet hit a shock wave (white) and get boosted to extreme speeds, emitting high-energy X-ray light. As they lose energy, the particles emit lower energy light in visible, infrared and radio wavelengths (purple and blue), and the jet becomes more turbulent. Credit: Pablo Garcia/MSFC/NASA.

    That’s exactly what the researchers saw, Liodakis says. “We got a clear result,” he says, that favors the shock wave explanation.

    There is still work to do to figure out the details of how the particles flow, says astrophysicist James Webb of Florida International University in Miami. For one, it’s not clear what would produce the shock. But “this is a step in the right direction,” he says. “It’s like opening a new window and looking at the object freshly, and we now see things we hadn’t seen before. It’s very exciting.”

    Science paper:
    Nature
    See the science paper for instructive material with images.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Imaging X-ray Polarimetry Explorer (IXPE) exploits the polarization state of light from astrophysical sources to provide insight into our understanding of X-ray production in objects such as neutron stars and pulsar wind nebulae, as well as stellar and supermassive black holes. Technical and science objectives include:

    Improving polarization sensitivity by two orders of magnitude over the X-ray polarimeter aboard the Orbiting Solar Observatory OSO-8 (scientists see HEASARC: OSO-8).
    Providing simultaneous spectral, spatial, and temporal measurements.
    Determining the geometry and the emission mechanism of Active Galactic Nuclei and microquasars.
    Finding the magnetic field configuration in magnetars and determining the magnitude of the field.
    Finding the mechanism for X ray production in pulsars (both isolated and accreting) and the geometry.
    Determining how particles are accelerated in Pulsar-Wind Nebulae.

    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra,
    Spitzer and associated programs, and now the NASA/ESA/CSA James Webb Space Telescope. NASA shares data with various national and international organizations such as from the The Japan Aerospace Exploration Agency [国立研究開発法人宇宙航空研究開発機構](JP).

    and

    The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)

     
  • richardmitnick 7:50 am on September 29, 2022 Permalink | Reply
    Tags: "Here is how olivine may trigger deep earthquakes", , , , , , , Science News   

    From “Science News” : “Here is how olivine may trigger deep earthquakes” 

    From “Science News”

    9.26.22
    Nikk Ogasa

    1
    The transformation of olivine (the yellow-green mineral seen in this rock) into wadsleyite hundreds of kilometers underground may set off the deepest earthquakes ever recorded. Credit: Joel Papalini/iStock/Getty Images Plus.

    Cocooned within the bowels of the Earth, one mineral’s metamorphosis into another may trigger some of the deepest earthquakes ever detected.

    These cryptic tremors — known as deep-focus earthquakes — are a seismic conundrum. They violently rupture at depths greater than 300 kilometers, where intense temperatures and pressures are thought to force rocks to flow smoothly. Now, experiments suggest that those same hellish conditions might also sometimes transform olivine — the primary mineral in Earth’s mantle — into the mineral wadsleyite. This mineral switch-up can destabilize the surrounding rock, enabling earthquakes at otherwise impossible depths, mineral physicist Tomohiro Ohuchi and colleagues report September 15 in Nature Communications [below].

    “It’s been a real puzzle for many scientists because earthquakes shouldn’t occur deeper than 300 kilometers,” says Ohuchi, of Ehime University in Matsuyama, Japan.

    Fig. 1: Summary of experimental conditions.
    2
    a Throughgoing faulting occurred. b No throughgoing faulting occurred. The long-dashed arrows indicate the P-T-t paths for our experiments. Squares, triangles, and diamonds represent the P-T-t path#1 (normal), #2 (overpressurized just before the deformation), and #3 (temperature ramping during the deformation), respectively. Large symbols represent the runs with throughgoing faulting (M2676, M3100, and M3425). Crosses show the lower limit of the peak temperature during the throughgoing faulting (estimated from the microstructures: see text for details). Short dashed lines are the estimated T-paths of shear heating. Red thick arrows show the temperature ranges during each deformation run of path#3. Solid and open symbols represent the runs in which the OL100 and OL92 samples were used, respectively. The equilibrium boundaries of α (olivine), β (wadsleyite), and γ (ringwoodite) for Mg1.8Fe0.2SiO4 are shown by gray solid lines14,34. Pale orange curve: solidus for dry lherzolite26. Dark-orange curve: liquidus for dry lherzolite26. Brown curve: melting of forsterite25. Pink curve: incongruent melting of γ-Fe2SiO4 to a liquid phase and stishovite (Sti)24 (i.e., the lower limit of the melting temperature of β/γ-Mg1.8Fe0.2SiO4). The M2472 run, in which a blow-out occurred in the early stage of deformation, is not shown.

    Fig. 2: Summary of experimental results as a function of temperature.
    3
    a Temperature dependence of the yield strength of the samples. Creep strength of olivine (Ol) is calculated assuming the Peierls creep for sintered dry/wet aggregates15,16,17, wet dislocation (disl.) creep18 and wet dislocation-accommodated grain boundary sliding (dislGBS; for a typical grain size of 10 µm)19. Water content of 190 wt. ppm is assumed for the calculations. b Temperature dependence of averaged acoustic emission (AE) rate (symbols) and cumulative AE energy release (gray bars). Symbols and red thick-arrows are the same as those in Fig. 1. The error bars represent the uncertainties in temperature or stress.

    More instructive images are available in the science paper.

    Deep-focus earthquakes usually occur at subduction zones where tectonic plates made of oceanic crust — rich in olivine — plunge toward the mantle (SN: 1/13/21). Since the quakes’ seismic waves lose strength during their long ascent to the surface, they aren’t typically dangerous. But that doesn’t mean the quakes aren’t sometimes powerful. In 2013, a magnitude 8.3 deep-focus quake struck around 609 kilometers below the Sea of Okhotsk, just off Russia’s eastern coast.

    Past studies [Nature Letters (below)] hinted that unstable olivine crystals could spawn deep quakes. But those studies tested other minerals that were similar in composition to olivine but deform at lower pressures, Ohuchi says, or the experiments didn’t strain samples enough to form faults.

    He and his team decided to put olivine itself to the test. To replicate conditions deep underground, the researchers heated and squeezed olivine crystals up to nearly 1100° Celsius and 17 gigapascals. Then the team used a mechanical press to further compress the olivine slowly and monitored the deformation.

    From 11 to 17 gigapascals and about 800° to 900° C, the olivine recrystallized into thin layers containing new wadsleyite and smaller olivine grains. The researchers also found tiny faults and recorded bursts of sound waves — indicative of miniature earthquakes. Along subducting tectonic plates, many of these thin layers grow and link to form weak regions in the rock, upon which faults and earthquakes can initiate, the researchers suggest.

    “The transformation really wreaks havoc with the [rock’s] mechanical stability,” says geophysicist Pamela Burnley of the University of Nevada, Las Vegas, who was not involved in the research. The findings help confirm that olivine transformations are enabling deep-focus earthquakes, she says.

    Next, Ohuchi’s team plans to experiment on olivine at even higher pressures to gain insights into the mineral’s deformation at greater depths.

    Science paper:
    Nature Communications
    Nature Letters

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

     
  • richardmitnick 7:18 am on September 29, 2022 Permalink | Reply
    Tags: "Mangrove forests expand and contract with a lunar cycle", , , , Science News   

    From Macquarie University (AU) Via “Science News” : “Mangrove forests expand and contract with a lunar cycle” 

    From Macquarie University (AU)

    Via

    “Science News”

    9.26.22
    Katherine Kornei

    1
    Mangrove forests in Australia (one shown) tend to grow according to a roughly 18-year lunar cycle, a new study finds.
    Credit: Krzysztof Dydynski/Lonely Planet RF/Getty Images.

    The glossy leaves and branching roots of mangroves are downright eye-catching, and now a study finds that the moon plays a special role in the vigor of these trees.

    Long-term tidal cycles set in motion by the moon drive, in large part, the expansion and contraction of mangrove forests in Australia, researchers report in the Sept. 16 Science Advances [below]. This discovery is key to predicting when stands of mangroves, which are good at sequestering carbon and could help fight climate change, are most likely to proliferate (SN: 11/18/21). Such knowledge could inform efforts to protect and restore the forests.

    Fig. 1. Long-phase tidal cycles influencing Australian coastal bioregions.
    2
    The modeled influence of the 18.6-year nodal cycle (A) and the 4.4-year perigean cycle (B) on tidal amplitude (Materials and Methods). Tidal form factor (C) ranges from semidiurnal (3), which influences the phasing of the nodal tidal cycle. Tidal range (D) varies markedly between bioregions.

    Fig. 2. Fitted overall trends of mangrove area and canopy condition (proportion of closed forest) Black lines are the estimate, and gray shaded areas are 95% confident intervals.
    3
    Across the coastal bioregions, both the extent and canopy condition of mangrove increased significantly (P < 0.001 for both canopy condition model and area model; table S1). The partial effect is the effect of “year” on the dependent variable when the other independent variables are kept constant.

    More instructive images are available in the science paper.

    Mangroves are coastal trees that provide habitat for fish and buffer against erosion (SN: 9/14/22). But in some places, the forests face a range of threats, including coastal development, pollution and land clearing for agriculture. To get a bird’s-eye view of these forests, Neil Saintilan, an environmental scientist at Macquarie University in Sydney, and his colleagues turned to satellite imagery. Using NASA and U.S. Geological Survey Landsat data from 1987 to 2020, the researchers calculated how the size and density of mangrove forests across Australia changed over time.

    After accounting for persistent increases in these trees’ growth — probably due to rising carbon dioxide levels, higher sea levels and increasing air temperatures — Saintilan and his colleagues noticed a curious pattern. Mangrove forests tended to expand and contract in both extent and canopy cover in a predictable manner. “I saw this 18-year oscillation,” Saintilan says.

    That regularity got the researchers thinking about the moon. Earth’s nearest celestial neighbor has long been known to help drive the tides, which deliver water and necessary nutrients to mangroves. A rhythm called the lunar nodal cycle could explain the mangroves’ growth pattern, the team hypothesized.

    Over the course of 18.6 years, the plane of the moon’s orbit around Earth slowly tips. When the moon’s orbit is the least tilted relative to our planet’s equator, semidiurnal tides — which consist of two high and two low tides each day — tend to have a larger range. That means that in areas that experience semidiurnal tides, higher high tides and lower low tides are generally more likely. The effect is caused by the angle at which the moon tugs gravitationally on the Earth.

    Saintilan and his colleagues found that mangrove forests experiencing semidiurnal tides tended to be larger and denser precisely when higher high tides were expected based on the moon’s orbit. The effect even seemed to outweigh other climatic drivers of mangrove growth, such as El Niño conditions. Other regions with mangroves, such as Vietnam and Indonesia, probably experience the same long-term trends, the team suggests.

    Having access to data stretching back decades was key to this discovery, Saintilan says. “We’ve never really picked up before some of these longer-term drivers of vegetation dynamics.”

    It’s important to recognize this effect on mangrove populations, says Octavio Aburto-Oropeza, a marine ecologist at the Scripps Institution of Oceanography in La Jolla, Calif., who was not involved in the research.

    Scientists now know when some mangroves are particularly likely to flourish and should make an extra effort at those times to promote the growth of these carbon-sequestering trees, Aburto-Oropeza says. That might look like added limitations on human activity nearby that could harm the forests, he says. “We should be more proactive.”

    Science paper:
    Science Advances

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Macquarie University campus

    Established in 1964, Macquarie University (AU)began as a bold experiment in higher education. Built to break from traditions: to be distinctive, progressive, and to be transformational. Today our pioneering history continues to be a source of inspiration as we celebrate our place among the best and brightest minds.

    Recognised internationally, Macquarie University is consistently ranked in the top two per cent of universities in the world* and within the top 10 in Australia*.

    Our research is leading the way in ground-breaking discoveries. Our academics are at the forefront of innovation and, as accomplished researchers, we are embracing the opportunity to tackle the big issues of our time.

    Led by the Vice-Chancellor, Professor S Bruce Dowton, Macquarie is home to five faculties. The fifth and newest – Faculty of Medicine and Health Sciences – was formed in 2014. We are also home to some of Australia’s most exceptional facilities – hubs of innovation that unite our students, researchers, academics and partners to achieve extraordinary things.

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  • richardmitnick 8:09 am on August 25, 2022 Permalink | Reply
    Tags: "The discovery of the Kuiper Belt revamped our view of the solar system", , , , , Science News, Thirty years ago astronomers learned that Pluto had neighbors.   

    From “Science News” : “The discovery of the Kuiper Belt revamped our view of the solar system” 

    From “Science News”

    8.23.22
    Katherine Kornei

    1
    The solar system’s Kuiper Belt is beyond Neptune’s orbit and home to Pluto and a slew of other icy bodies. Credit: Ari Gea/SayoStudio.

    Thirty years ago astronomers learned that Pluto had neighbors.

    On a Hawaiian mountaintop in the summer of 1992, a pair of scientists spotted a pinprick of light inching through the constellation Pisces. That unassuming object — located over a billion kilometers beyond Neptune — would rewrite our understanding of the solar system.

    Rather than an expanse of emptiness, there was something, a vast collection of things in fact, lurking beyond the orbits of the known planets.

    The scientists had discovered the Kuiper Belt, a doughnut-shaped swath of frozen objects left over from the formation of the solar system.

    As researchers learn more about the Kuiper Belt, the origin and evolution of our solar system is coming into clearer focus. Closeup glimpses of the Kuiper Belt’s frozen worlds have shed light on how planets, including our own, might have formed in the first place. And surveys of this region, which have collectively revealed thousands of such bodies, called Kuiper Belt objects, suggest that the early solar system was home to pinballing planets.

    The humble object that kick-started it all is a chunk of ice and rock roughly 250 kilometers in diameter. It was first spotted 30 years ago this month.

    Staring into space

    In the late 1980s, planetary scientist David Jewitt and astronomer Jane Luu, both at MIT at the time, were several years into a curious quest. The duo had been using telescopes in Arizona to take images of patches of the night sky with no particular target in mind. “We were literally just staring off into space looking for something,” says Jewitt, now at UCLA.

    An apparent mystery motivated the researchers: The inner solar system is relatively crowded with rocky planets, asteroids and comets, but there was seemingly not much out beyond the gas giant planets, besides small, icy Pluto. “Maybe there were things in the outer solar system,” says Luu, who now works at the University of Oslo and Boston University. “It seemed like a worthwhile thing to check out.”

    Poring over glass photographic plates and digital images of the night sky, Jewitt and Luu looked for objects that moved extremely slowly, a telltale sign of their great distance from Earth. But the pair kept coming up empty. “Years went by, and we didn’t see anything,” Luu says. “There was no guarantee this was going to work out.”

    The tide changed in 1992. On the night of August 30, Jewitt and Luu were using a University of Hawaii telescope on the Big Island. They were employing their usual technique for searching for distant objects: Take an image of the night sky, wait an hour or so, take another image of the same patch of sky, and repeat. An object in the outer reaches of the solar system would shift position ever so slightly from one image to the next, primarily because of the movement of Earth in its orbit. “If it’s a real object, it would move systematically at some predicted rate,” Luu says.

    By 9:14 p.m. that evening, Jewitt and Luu had collected two images of the same bit of the constellation Pisces. The researchers displayed the images on the bulbous cathode-ray tube monitor of their computer, one after the other, and looked for anything that had moved. One object immediately stood out: A speck of light had shifted just a touch to the west.

    But it was too early to celebrate. Spurious signals from high-energy particles zipping through space — cosmic rays — appear in images of the night sky all of the time. The real test would be whether this speck showed up in more than two images, the researchers knew.

    Jewitt and Luu nervously waited until 11 p.m. for the telescope’s camera to finish taking a third image. The same object was there, and it had moved a bit farther west. A fourth image, collected just after midnight, revealed the object had shifted position yet again. This is something real, Jewitt remembers thinking. “We were just blown away.”

    2
    The way the circled object shifted position in the sky (time stamps at right) told Jewitt and Luu that the object, dubbed 1992 QB1, was distant. It was the first evidence of the icy zone called the Kuiper Belt.D. Jewitt/UCLA.

    Based on the object’s brightness and its leisurely pace — it would take nearly a month for it to march across the width of the full moon as seen from Earth — Jewitt and Luu did some quick calculations. This thing, whatever it was, was probably about 250 kilometers in diameter. That’s sizable, about one-tenth the width of Pluto. It was orbiting far beyond Neptune. And in all likelihood, it wasn’t alone.

    Although Jewitt and Luu had been diligently combing the night sky for years, they had observed only a tiny fraction of it. There were possibly thousands more objects out there like this one just waiting to be found, the two concluded.

    The realization that the outer solar system was probably teeming with undiscovered bodies was mind-blowing, Jewitt says. “We expanded the known volume of the solar system enormously.” The object that Jewitt and Luu had found, 1992 QB1 (SN: 9/26/92, p. 196), introduced a whole new realm.

    Just a few months later, Jewitt and Luu spotted a second object also orbiting far beyond Neptune (SN: 4/10/93, p. 231). The floodgates opened soon after. “We found 40 or 50 in the next few years,” Jewitt says. As the digital detectors that astronomers used to capture images grew in size and sensitivity, researchers began uncovering droves of additional objects. “So many interesting worlds with interesting stories,” says Mike Brown, an astronomer at Caltech who studies Kuiper Belt objects.

    Finding all of these frozen worlds, some orbiting even beyond Pluto, made sense in some ways, Jewitt and Luu realized. Pluto had always been an oddball; it’s a cosmic runt (smaller than Earth’s moon) and looks nothing like its gas giant neighbors. What’s more, its orbit takes it sweeping far above and below the orbits of the other planets. Maybe Pluto belonged not to the world of the planets but to the realm of whatever lay beyond, Jewitt and Luu hypothesized. “We suddenly understood why Pluto was such a weird planet,” Jewitt says. “It’s just one object, maybe the biggest, in a set of bodies that we just stumbled across.” Pluto probably wouldn’t be a member of the planet club much longer, the two predicted. Indeed, by 2006, it was out (SN: 9/2/06, p. 149).

    Up-close look

    The discovery of 1992 QB1 opened the world’s eyes to the Kuiper Belt, named after Dutch-American astronomer Gerard Kuiper. In a twist of history, however, Kuiper predicted that this region of space would be empty. In the 1950s, he proposed that any occupants that might have once existed there would have been banished by gravity to even more distant reaches of the solar system.

    In other words, Kuiper anti-predicted the existence of the Kuiper Belt. He turned out to be wrong.

    Today, researchers know that the Kuiper Belt stretches from a distance of roughly 30 astronomical units from the sun — around the orbit of Neptune — to roughly 55 astronomical units. It resembles a puffed-up disk, Jewitt says. “Superficially, it looks like a fat doughnut.”

    The frozen bodies that populate the Kuiper Belt are the remnants of the swirling maelstrom of gas and dust that birthed the sun and the planets. There’s “a bunch of stuff that’s left over that didn’t quite get built up into planets,” says astronomer Meredith MacGregor of the University of Colorado-Boulder. When one of those cosmic leftovers gets kicked into the inner solar system by a gravitational shove from a planet like Neptune and approaches the sun, it turns into an object we recognize as a comet (SN: 9/12/20, p. 14). Comets that circle the sun once only every 200 years or more typically derive from the solar system’s even more distant repository of icy bodies known as the Oort cloud.

    3
    There are many places in the solar system where icy bodies congregate: the asteroid belt roughly between Jupiter and Mars (top), the doughnut-shaped Kuiper Belt beyond the gas giant planets (middle) and the most distant zone, the Oort cloud (bottom).Mark Garlick/Science Source

    In scientific parlance, the Kuiper Belt is a debris disk (SN Online: 7/28/21). Distant solar systems contain debris disks, too, scientists have discovered [The Astrophysical Journal (below)]. “They’re absolutely directly analogous to our Kuiper Belt,” MacGregor says [The Astrophysical Journal (below)].

    In 2015, scientists got their first close look at a Kuiper Belt object when NASA’s New Horizons spacecraft flew by Pluto (SN Online: 7/15/15).

    The pictures that New Horizons returned in the following years were thousands of times more detailed than previous observations of Pluto and its moons. No longer just a few fuzzy pixels, the worlds were revealed as rich landscapes of ice-spewing volcanoes and deep, jagged canyons (SN: 6/22/19, p. 12; SN Online: 7/13/18). “I’m just absolutely ecstatic with what we accomplished at Pluto,” says Marc Buie, an astronomer at the Southwest Research Institute in Boulder, Colo., and a member of the New Horizons team. “It could not possibly have gone any better.”

    But New Horizons wasn’t finished with the Kuiper Belt. On New Year’s Day of 2019, when the spacecraft was almost 1.5 billion kilometers beyond Pluto’s orbit, it flew past another Kuiper Belt object. And what a surprise it was. Arrokoth — its name refers to “sky” in the Powhatan/Algonquian language — looks like a pair of pancakes joined at the hip (SN: 12/21/19 & 1/4/20, p. 5; SN: 3/16/19, p. 15). Roughly 35 kilometers long from end to end, it was probably once two separate bodies that gently collided and stuck. Arrokoth’s bizarre structure sheds light on a fundamental question in astronomy: How do gas and dust clump together and grow into larger bodies?

    One long-standing theory, called planetesimal accretion, says that a series of collisions is responsible. Tiny bits of material collide and stick together on repeat to build up larger and larger objects, says JJ Kavelaars, an astronomer at the University of Victoria and the National Research Council of Canada. But there’s a problem, Kavelaars says.

    4
    In 2019, New Horizons flew by Arrokoth (above), a roughly 35-kilometer-long Kuiper Belt object.NASA, JHU-APL, SWRI.

    As objects get large enough to exert a significant gravitational pull, they accelerate as they approach one another. “They hit each other too fast, and they don’t stick together,” he says. It would be unusual for a large object like Arrokoth, particularly with its two-lobed structure, to have formed from a sequence of collisions.

    More likely, Arrokoth was born from a process known as gravitational instability, researchers now believe. In that scenario, a clump of material that happens to be denser than its surroundings grows by pulling in gas and dust. This process can form planets on timescales of thousands of years, rather than the millions of years required for planetesimal accretion. “The timescale for planet formation completely changes,” Kavelaars says.

    If Arrokoth formed this way, other bodies in the solar system probably did too. That may mean that parts of the solar system formed much more rapidly than previously believed, says Buie, who discovered Arrokoth in 2014. “Already Arrokoth has rewritten the textbooks on how solar system formation works.”

    What they’ve seen so far makes scientists even more eager to study another Kuiper Belt object up close. New Horizons is still making its way through the Kuiper Belt, but time is running out to identify a new object and orchestrate a rendezvous. The spacecraft, which is currently 53 astronomical units from the sun, is approaching the Kuiper Belt’s outer edge. Several teams of astronomers are using telescopes around the world to search for new Kuiper Belt objects that would make a close pass to New Horizons. “We are definitely looking,” Buie says. “We would like nothing better than to fly by another object.”

    All eyes on the Kuiper Belt

    Astronomers are also getting a wide-angle view of the Kuiper Belt by surveying it with some of Earth’s largest telescopes. At the Canada-France-Hawai’i Telescope on Mauna Kea — the same mountaintop where Jewitt and Luu spotted 1992 QB1 — astronomers recently wrapped up the Outer Solar System Origins Survey.

    It recorded more than 800 previously unknown Kuiper Belt objects, bringing the total number known to roughly 3,000.

    This cataloging work is revealing tantalizing patterns in how these bodies move around the sun, MacGregor says. Rather than being uniformly distributed, the orbits of Kuiper Belt objects tend to be clustered in space. That’s a telltale sign that these bodies got a gravitational shove in the past, she says.

    The cosmic bullies that did that shoving, most astronomers believe, were none other than the solar system’s gas giants. In the mid-2000s, scientists first proposed that planets like Neptune and Saturn probably pinballed toward and away from the sun early in the solar system’s history (SN: 5/5/12, p. 24). That movement explains the strikingly similar orbits of many Kuiper Belt objects, MacGregor says. “The giant planets stirred up all of the stuff in the outer part of the solar system.”

    Refining the solar system’s early history requires observations of even more Kuiper Belt objects, says Meg Schwamb, an astronomer at Queen’s University Belfast in Northern Ireland. Researchers expect that a new astronomical survey, slated to begin next year, will find roughly 40,000 more Kuiper Belt objects. The Vera C. Rubin Observatory, being built in north-central Chile, will use its 3,200-megapixel camera to repeatedly photograph the entire Southern Hemisphere sky every few nights for 10 years.

    That undertaking, the Legacy Survey of Space and Time, or LSST, will revolutionize our understanding of how the early solar system evolved, says Schwamb, a cochair of the LSST Solar System Science Collaboration.

    It’s exciting to think about what we might learn next from the Kuiper Belt, Jewitt says. The discoveries that lay ahead will be possible, in large part, because of advances in technology, he says. “One picture with one of the modern survey cameras is roughly a thousand pictures with our setup back in 1992.”

    But even as we uncover more about this distant realm of the solar system, a bit of awe should always remain, Jewitt says. “It’s the largest piece of the solar system that we’ve yet observed.”

    Science papers:
    The Astrophysical Journal 2017
    The Astrophysical Journal 2017
    Nature 1993

    See the full article here .


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  • richardmitnick 9:57 am on July 28, 2022 Permalink | Reply
    Tags: "Quantum entanglement makes quantum communication even more secure", "Quantum entanglement": a mysterious relationship between particles that links their properties even when separated over long distances., , , , Science News   

    From “Science News”: “Quantum entanglement makes quantum communication even more secure” 

    From “Science News”

    7.27.22
    Emily Conover

    Three studies show quantum devices don’t have to be perfectly understood to be snoop-proof.

    1
    Quantum entanglement, a type of ethereal link between particles, improves the security of quantum communication, as demonstrated in three experiments (the one pictured, by researchers in France, Switzerland and England, used strontium ions in its test). Credit: David Nadlinger/University of Oxford.

    Stealthy communication just got more secure, thanks to quantum entanglement.

    Quantum physics provides a way to share secret information that’s mathematically proven to be safe from the prying eyes of spies. But until now, demonstrations of the technique, called quantum key distribution, rested on an assumption: The devices used to create and measure quantum particles have to be known to be flawless. Hidden defects could allow a stealthy snoop to penetrate the security unnoticed.

    Now, three teams of researchers have demonstrated the ability to perform secure quantum communication without prior confirmation that the devices are foolproof. Called device-independent quantum key distribution, the method is based on quantum entanglement, a mysterious relationship between particles that links their properties even when separated over long distances.

    In everyday communication, such as the transmission of credit card numbers over the internet, a secret code, or key, is used to garble the information, so that it can be read only by someone else with the key. But there’s a quandary: How can a distant sender and receiver share that key with one another while ensuring that no one else has intercepted it along the way?

    Quantum physics provides a way to share keys by transmitting a series of quantum particles, such as particles of light called photons, and performing measurements on them. By comparing notes, the users can be sure that no one else has intercepted the key. Those secret keys, once established, can then be used to encrypt the sensitive intel (SN: 12/13/17). By comparison, standard internet security rests on a relatively shaky foundation of math problems that are difficult for today’s computers to solve, which could be vulnerable to new technology, namely quantum computers (SN: 6/29/17).

    But quantum communication typically has a catch. “There cannot be any glitch that is unforeseen,” says quantum physicist Valerio Scarani of the National University of Singapore. For example, he says, imagine that your device is supposed to emit one photon but unknown to you, it emits two photons. Any such flaws would mean that the mathematical proof of security no longer holds up. A hacker could sniff out your secret key, even though the transmission seems secure.

    Device-independent quantum key distribution can rule out such flaws. The method builds off of a quantum technique known as a Bell test, which involves measurements of entangled particles. Such tests can prove that quantum mechanics really does have “spooky” properties, namely nonlocality, the idea that measurements of one particle can be correlated with those of a distant particle. In 2015, researchers performed the first “loophole-free” Bell tests, which certified beyond a doubt that quantum physics’ counterintuitive nature is real (SN: 12/15/15).

    “The Bell test basically acts as a guarantee,” says Jean-Daniel Bancal of CEA Saclay in France. A faulty device would fail the test, so “we can infer that the device is working properly.”

    In their study, Bancal and colleagues used entangled, electrically charged strontium atoms separated by about two meters. Measurements of those ions certified that their devices were behaving properly, and the researchers generated a secret key, the team reports in the July 28 Nature [below].

    Typically, quantum communication is meant for long-distance dispatches. (To share a secret with someone two meters away, it would be easier to simply walk across the room.) So Scarani and colleagues studied entangled rubidium atoms 400 meters apart. The setup had what it took to produce a secret key, the researchers report in the same issue of Nature below]. But the team didn’t follow the process all the way through: The extra distance meant that producing a key would have taken months.

    In the third study, published in the July 29 Physical Review Letters [below], researchers wrangled entangled photons rather than atoms or ions. Physicist Wen-Zhao Liu of the University of Science and Technology of China in Hefei and colleagues also demonstrated the capability to generate keys, at distances up to 220 meters. This is particularly challenging to do with photons, Liu says, because photons are often lost in the process of transmission and detection.

    Loophole-free Bell tests are already no easy feat, and these techniques are even more challenging, says physicist Krister Shalm of the National Institute of Standards and Technology in Boulder, Colo. “The requirements for this experiment are so absurdly high that it’s just an impressive achievement to be able to demonstrate some of these capabilities,” says Shalm, who wrote a perspective in the same issue of Nature [below].

    That means that the technique won’t see practical use anytime soon, says physicist Nicolas Gisin of the University of Geneva, who was not involved with the research.

    Still, device-independent quantum key distribution is “a totally fascinating idea,” Gisin says. Bell tests were designed to answer a philosophical question about the nature of reality — whether quantum physics really is as weird as it seems. “To see that this now becomes a tool that enables something else,” he says, “this is the beauty.”

    Science papers:
    Nature

    Nature

    Physical Review Letters

    Nature

    See the full article here .


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  • richardmitnick 8:50 am on July 14, 2022 Permalink | Reply
    Tags: "The most distant rotating galaxy hails from 13.3 billion years ago", , , , , Science News, The galaxy MACS1149-JD1 started spinning just 500 million years after the Big Bang.   

    From “Science News”: “The most distant rotating galaxy hails from 13.3 billion years ago” 

    From “Science News”

    7.13.22
    Lisa Grossman

    The galaxy MACS1149-JD1 started spinning just 500 million years after the Big Bang.

    1
    The galaxy MACS1149-JD1 about 13.3 billion light-years away (inset in this image of a galaxy cluster from the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array) is the most distant galaxy to show signs of rotation.

    ALMA/ESO, NAOJ and NRAO; NASA, ESA Hubble Space Telescope; W. Zheng/JHU, M. Postman/STScI; the CLASH Team; T. Hasimoto et al/Nature 2018

    There is a galaxy spinning like a record in the early universe — far earlier than any others have been seen twirling around.

    Astronomers have spotted signs of rotation in the galaxy MACS1149-JD1, JD1 for short, which sits so far away that its light takes 13.3 billion years to reach Earth. “The galaxy we analyzed, JD1, is the most distant example of a rotational galaxy,” says astronomer Akio Inoue of Waseda University in Tokyo.

    “The origin of the rotational motion in galaxies is closely related to a question: how galaxies like the Milky Way formed,” Inoue says. “So, it is interesting to find the onset of rotation in the early universe.”

    JD1 was discovered in 2012. Due to its great distance from Earth, its light had been stretched, or redshifted, into longer wavelengths, thanks to the expansion of the universe. That redshifted light revealed that JD1 existed just 500 million years after the Big Bang.

    Astronomers used light from the entire galaxy to make that measurement. Now, using the Atacama Large Millimeter/submillimeter Array in Chile for about two months in 2018, Inoue and colleagues have measured more subtle differences in how that light is shifted across the galaxy’s disk. The new data show that, while all of JD1 is moving away from Earth, its northern part is moving away slower than the southern part.

    JD1 spins at about 180,000 kilometers per hour, roughly a quarter the spin speed of the Milky Way. The galaxy is also smaller than modern spiral galaxies. So JD1 may be just starting to spin, Inoue says.

    The James Webb Space Telescope will observe JD1 in the next year to reveal more clues to how that galaxy, and others like ours, formed.

    The researchers report in the July 1 Astrophysical Journal Letters.

    See the full article here .


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  • richardmitnick 10:28 am on April 21, 2022 Permalink | Reply
    Tags: "'Goldilocks' stars may pose challenges for any nearby habitable planets", , , , , Far-ultraviolet radiation from orange dwarfs could endanger planetary atmospheres., Science News   

    From Science News: “‘Goldilocks’ stars may pose challenges for any nearby habitable planets” 

    From Science News

    April 20, 2022
    Ken Croswell

    Far-ultraviolet radiation from orange dwarfs could endanger planetary atmospheres.

    1
    Orange dwarfs, such as those of the nearby double-star system 70 Ophiuchi (illustrated), could have life-bearing planets — but not if far-ultraviolet light leads to the destruction of their atmospheres. Credit: Chris Butler/Science Source.

    Some astronomers have called these orange suns “Goldilocks stars” (SN: 11/18/09). They are dimmer and age more slowly than yellow sunlike stars, thus offering an orbiting planet a more stable climate. But they are brighter and age faster than red dwarfs, which often spew large flares. However, new observations show that orange dwarfs emit lots of ultraviolet light long after birth, potentially endangering planetary atmospheres, researchers report in a paper submitted March 29.

    Using data from the Hubble Space Telescope, astronomer Tyler Richey-Yowell and her colleagues examined 39 orange dwarfs. Most are moving together through the Milky Way in two separate groups, either 40 million or 650 million years old.

    To Richey-Yowell’s surprise, she and her team found that the ultraviolet flux didn’t drop off from the younger orange stars to the older ones — unlike the case for yellow and red stars. “I was like, `What the heck is going on?’” says Richey-Yowell, of Arizona State University in Tempe.

    In a stroke of luck, another team of researchers supplied part of the answer. As yellow sunlike stars age, they spin more slowly, causing them to be less active and emit less UV radiation. But for orange dwarfs, this steady spin-down stalls when the stars are roughly a billion years old, astronomer Jason Lee Curtis at Columbia University and colleagues reported in 2019.

    “[Orange] stars are just much more active for a longer time than we thought they were,” Richey-Yowell says. That means these possibly not-so-Goldilocks stars probably maintain high levels of UV light for more than a billion years.

    And that puts any potential life-forms inhabiting orbiting planets on notice. Far-ultraviolet light — whose photons, or particles of light, have much more energy than the UV photons that give you vitamin D — tears molecules in a planet’s atmosphere apart. That leaves behind individual atoms and electrically charged atoms and groups of atoms known as ions. Then the star’s wind — its outflow of particles — can carry the ions away, stripping the planet of its air.

    But not all hope is lost for aspiring life-forms that have an orange dwarf sun. Prolonged exposure to far-ultraviolet light can stress planets but doesn’t necessarily doom them to be barren, says Ed Guinan, an astronomer at Villanova University in Pennsylvania who was not involved in the new work. “As long as the planet has a strong magnetic field, you’re more or less OK,” he says.

    Though far-ultraviolet light splits water and other molecules in a planet’s atmosphere, the star’s wind can’t remove the resulting ions if a magnetic field as strong as Earth’s protects them. “That’s why the Earth survived” as a life-bearing world, Guinan says. In contrast, Venus might never have had a magnetic field, and Mars lost its magnetic field early on and most of its air soon after.

    “If the planet doesn’t have a magnetic field or has a weak one,” Guinan says, “the game is over.”

    What’s needed, Richey-Yowell says, is a study of older orange dwarfs to see exactly when their UV output declines. That will be a challenge, though. The easiest way to find stars of known age is to study a cluster of stars, but most star clusters get ripped apart well before their billionth birthday (SN: 7/24/20). As a result, star clusters somewhat older than this age are rare, which means the nearest examples are distant and harder to observe.

    See the full article here .


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  • richardmitnick 10:58 am on April 14, 2022 Permalink | Reply
    Tags: "How ancient and recurring climate changes may have shaped human evolution", , , Science News   

    FromScience News: “How ancient and recurring climate changes may have shaped human evolution” 

    From Science News

    4.13.22
    Bruce Bower

    1
    A new study claims climate change–induced travels of a disputed hominid species called Homo heidelbergensis, represented here by a roughly 600,000-year-old East African skull, led to the evolution of H. sapiens in southern Africa and Neandertals in Europe. Credit: Ryan Somma/Flickr (CC BY-SA 2.0)

    Recurring climate changes may have orchestrated where Homo species lived over the last 2 million years and how humankind evolved.

    Ups and downs in temperature, rainfall and plant growth promoted ancient hominid migrations within and out of Africa that fostered an ability to survive in unfamiliar environments, say climate physicist and oceanographer Axel Timmermann and colleagues. Based on how the timing of ancient climate variations matched up with the comings and goings of different fossil Homo species, the researchers generated a novel — and controversial — outline of human evolution. Timmermann, of Pusan National University [부산대학교](KR), and his team present that scenario April 13, 2022 in Nature.

    Here’s how these scientists tell the story of humankind, starting roughly 2 million years ago. By that time, Homo erectus had already begun to roam outside Africa, while an East African species called H. ergaster stuck close to its home region. H. ergaster probably evolved into a disputed East African species called H. heidelbergensis, which split into southern and northern branches between 850,000 and 600,000 years ago. These migrations coincided with warmer, survival-enhancing climate shifts that occur every 20,000 to 100,000 years due to variations in Earth’s orbit and tilt that modify how much sunlight reaches the planet.

    Then, after traveling north to Eurasia, H. heidelbergensis possibly gave rise to Denisovans around 430,000 years ago, the researchers say. And in central Europe, harsh habitats created by recurring ice ages spurred the evolution of H. heidelbergensis into Neandertals between 400,000 and 300,000 years ago. Finally, in southern Africa between 310,000 and 200,000 years ago, increasingly harsh environmental conditions accompanied a transition from H. heidelbergensis to H. sapiens, who later moved out of Africa.

    But some researchers contend [Evolutionary Anthropology] that H. heidelbergensis, as defined by its advocates, contains too many hard-to-categorize fossils to qualify as a species.

    An alternative view to the newly proposed scenario suggests that, during the time that H. heidelbergensis allegedly lived, closely related Homo populations periodically split up, reorganized and bred with outsiders, without necessarily operatingIt has proven difficult to show more definitively that ancient environmental changes caused transitions in hominid evolution. For instance, a previous proposal that abrupt climate shifts resulted in rainy, resource-rich stretches of southern Africa’s coast, creating conditions where H. sapiens then evolved (SN: 3/31/21), still lacks sufficient climate, fossil and other archaeological evidence. as distinct biological species (SN: 12/13/21). In this view, mating among H. sapiens groups across Africa starting as early as 500,000 years ago eventually produced a physical makeup typical of people today. If so, that would undermine the validity of a neatly branching evolutionary tree of Homo species leading up to H. sapiens, as proposed by Timmermann’s group.

    The new scenario derives from a computer simulation of the probable climate over the last 2 million years, in 1,000-year intervals, across Africa, Asia and Europe. The researchers then examined the relationship between simulated predictions of what ancient habitats were like in those regions and the dates of known hominid fossil and archaeological sites. Those sites range in age from around 2 million to 30,000 years old.

    Previous fossil evidence indicates that H. erectus spread as far as East Asia and Java (SN: 12/18/19). Timmermann’s climate simulations suggest that H. erectus, as well as H. heidelbergensis and H. sapiens, adapted to increasingly diverse habitats during extended travels. Those migrations stimulated brain growth and cultural innovations that “may have made [all three species] the global wanderers that they were,” Timmermann says.

    The new habitat simulations also indicate that H. sapiens was particularly good at adjusting to hot, dry regions, such as northeastern Africa and the Arabian Peninsula.

    Climate, habitat and fossil data weren’t sufficient to include additional proposed Homo species in the new evolutionary model, including H. floresiensis in Indonesia (SN: 3/30/16) and H. naledi in South Africa (SN: 5/9/17).

    It has proven difficult [Trends in Ecology and Evolution] to show more definitively that ancient environmental changes caused transitions in hominid evolution. For instance, a previous proposal that abrupt climate shifts resulted in rainy, resource-rich stretches of southern Africa’s coast, creating conditions where H. sapiens then evolved (SN: 3/31/21), still lacks sufficient climate, fossil and other archaeological evidence.

    Paleoanthropologist Rick Potts of the Smithsonian Institution in Washington, D.C., has developed another influential theory about how climate fluctuations influenced human evolution that’s still open to debate. A series of climate-driven booms and busts in resource availability, starting around 400,000 years ago in East Africa, resulted in H. sapiens evolving as a species with a keen ability to survive in unpredictably shifting environments, Potts argues (SN: 10/21/20). But the new model indicates that ancient H. sapiens often migrated into novel but relatively stable environments, Timmermann says, undermining support for Potts’ hypothesis, known as variability selection.

    The new findings need to be compared with long-term environmental records at several well-studied fossil sites in Africa and East Asia before rendering a verdict on variability selection, Potts says.

    The new model “provides a great framework” to evaluate ideas such as variability selection, says paleoclimatologist Rachel Lupien of Lamont-Doherty Earth Observatory in Palisades, N.Y. That’s especially true, Lupien says, if researchers can specify whether climate and ecosystem changes that played out over tens or hundreds of years were closely linked to ancient Homo migrations.

    For now, much remains obscured on the ancient landscape of human evolution.

    See the full article here.


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  • richardmitnick 9:51 am on April 3, 2022 Permalink | Reply
    Tags: "The universe’s background starlight is twice as bright as expected", , , , National Aeronautics Space Agency New Horizons spacecraft, Science News,   

    From Science News: “The universe’s background starlight is twice as bright as expected” 

    From Science News

    March 22, 2022
    Liz Kruesi

    1
    From a vantage point far from the sun and light-scattering interplanetary dust (illustrated, center), the New Horizons spacecraft is well-positioned to measure the visible background glow of the universe.Credit: The National Aeronautics and Space Administration, Joseph Olmsted/The Space Telescope Science Institute.

    Even when you remove the bright stars, the glowing dust and other nearby points of light from the inky, dark sky, a background glow remains. That glow comes from the cosmic sea of distant galaxies, the first stars that burned, faraway coalescing gas — and, it seems, something else in the mix that’s evading researchers.

    Astronomers estimated the amount of visible light pervading the cosmos by training the New Horizons spacecraft, which flew past Pluto in 2015, on a spot on the sky mostly devoid of nearby stars and galaxies (SN: 12/15/15).

    That estimate should match measurements of the total amount of light coming from galaxies across the history of the universe. But it doesn’t, researchers report in the March 1 Astrophysical Journal Letters.

    “It turns out that the galaxies that we know about can account for about half of the level we see,” says Tod Lauer, an astronomer at the National Science Foundation’s NOIRLab in Tucson, Ariz.

    For decades, astronomers have measured the extragalactic background light in different wavelengths, from radio waves to gamma rays (SN: 8/23/13; SN: 11/29/18). This provides a census of the universe and gives researchers hints into the processes that emit those types of light.

    But the background visible light — dubbed the cosmic optical background, or COB — is challenging to measure from the inner solar system. Here, lots of interplanetary dust scatters sunlight, washing out the much fainter COB. The Pluto-visiting New Horizons spacecraft, however, is far enough from the sun that scattered sunlight doesn’t flood the spacecraft’s images.

    2
    Sunlight scattering off dust near Earth makes for a lovely photograph (seen here from La Silla Observatory in Chile as a column of light), but it hampers observations of the faint cosmic background.Y. Beletsky/The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europaiche Sûdsternwarte] (EU)(CL).

    So in September 2021, Lauer and colleagues pointed the spacecraft’s LORRI camera toward a patch of sky and took a bunch of pictures.

    They digitally removed all known sources of light — individual stars, nearby galaxies, even heat from the spacecraft’s nuclear power source (SN: 2/18/16) — and measured what was left to estimate the COB.

    Then they used large archives of galaxy observations, like those from the Hubble Space Telescope, to calculate the light emitted by all the galaxies in the universe. The measured COB is roughly twice as bright as that calculation.

    While Lauer’s group previously noted a discrepancy [The Astrophysical Journal], this new measurement reveals a wider difference, and with smaller uncertainty. “There’s clearly an anomaly. Now we need to try to understand it and explain it,” says coauthor Marc Postman, an astronomer at the Space Telescope Science Institute in Baltimore, Md.

    There are several astronomical reasons that could explain the discrepancy. Perhaps, says Postman, rogue stars stripped from galaxies linger in intergalactic space. Or maybe, he says, there is “a very faint population of very compact galaxies that are just below the detection limits of Hubble.” If it’s the latter case, astronomers should know in the next couple years because NASA’s recently launched James Webb Space Telescope will see these even-fainter galaxies (SN: 10/6/21).

    Another possibility is the researchers missed something in their analysis. “I’m glad it got done; it’s absolutely a necessary measurement,” says astrophysicist Michael Zemcov of The Rochester Institute of Technology in New York who was not involved in this study. Perhaps they’re missing some additional glow from the New Horizons spacecraft and its LORRI instrument, or they didn’t factor in some additional foreground light. “I think there’s a conversation there about details.”

    See the full article here .

    See also the Noirlab UArizona STScI article here.


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  • richardmitnick 10:54 am on July 15, 2021 Permalink | Reply
    Tags: "Hurricanes may not be becoming more frequent but they’re still more dangerous", , , , , , Paleotempestology, , Science News   

    From Princeton University (US) and From National Oceanic and Atmospheric Administration (US) via Science News : “Hurricanes may not be becoming more frequent but they’re still more dangerous” 

    Princeton University

    From Princeton University (US)

    and

    From National Oceanic and Atmospheric Administration (US)

    via

    Science News

    July 13, 2021
    Carolyn Gramling

    There aren’t more of the storms now than there were roughly 150 years ago, a study suggests.

    1
    Hurricane Iota raged toward Central America on November 16, 2020, as a Category 5 storm — the 30th named storm in a record-breaking season. Iota’s rapid intensification may be linked to global warming, but a 150-year record of Atlantic hurricanes suggests no long-term trend in storm frequency. Credit: National Oceanic and Atmospheric Administration (US).

    Climate change is helping Atlantic hurricanes pack more of a punch, making them rainier, intensifying them faster and helping the storms linger longer even after landfall. But a new statistical analysis of historical records and satellite data suggests that there aren’t actually more Atlantic hurricanes now than there were roughly 150 years ago, researchers report July 13 in Nature Communications.

    The record-breaking number of Atlantic hurricanes in 2020, a whopping 30 named storms, led to intense speculation over whether and how climate change was involved (SN: 12/21/20). It’s a question that scientists continue to grapple with, says Gabriel Vecchi, a climate scientist at Princeton University (US). “What is the impact of global warming — past impact and also our future impact — on the number and intensity of hurricanes and tropical storms?”

    Satellite records over the last 30 years allow us to say “with little ambiguity how many hurricanes, and how many major hurricanes [Category 3 and above] there were each year,” Vecchi says. Those data clearly show that the number, intensity and speed of intensification of hurricanes has increased over that time span.

    But “there are a lot of things that have happened over the last 30 years” that can influence that trend, he adds. “Global warming is one of them.” Decreasing aerosol pollution is another (SN: 11/21/19). The amount of soot and sulfate particles and dust over the Atlantic Ocean was much higher in the mid-20th century than now; by blocking and scattering sunlight, those particles temporarily cooled the planet enough to counteract greenhouse gas warming. That cooling is also thought to have helped temporarily suppress hurricane activity in the Atlantic.

    To get a longer-term perspective on trends in Atlantic storms, Vecchi and colleagues examined a dataset of hurricane observations from the National Oceanic and Atmospheric Administration (US) that stretches from 1851 to 2019. It includes old-school observations by unlucky souls who directly observed the tempests as well as remote sensing data from the modern satellite era.

    2

    How to directly compare those different types of observations to get an accurate trend was a challenge. Satellites, for example, can see every storm, but earlier observations will count only the storms that people directly experienced. So the researchers took a probabilistic approach to fill in likely gaps in the older record, assuming, for example, that modern storm tracks are representative of pre-satellite storm tracks to account for storms that would have stayed out at sea and unseen. The team found no clear increase in the number of storms in the Atlantic over that 168-year time frame. One possible reason for this, the researchers say, is a rebound from the aerosol pollution–induced lull in storms that may be obscuring some of the greenhouse gas signal in the data.

    More surprisingly — even to Vecchi, he says — the data also seem to show no significant increase in hurricane intensity over that time. That’s despite “scientific consistency between theories and models indicating that the typical intensity of hurricanes is more likely to increase as the planet warms,” Vecchi says. But this conclusion is heavily caveated — and the study also doesn’t provide evidence against the hypothesis that global warming “has acted and will act to intensify hurricane activity,” he adds.

    Climate scientists were already familiar with the possibility that storm frequency might not have increased much in the last 150 or so years — or over much longer timescales. The link between number of storms and warming has long been uncertain, as the changing climate also produces complex shifts in atmospheric patterns that could take the hurricane trend in either direction. The Intergovernmental Panel on Climate Change noted in a 2012 report that there is “low confidence” that tropical cyclone activity has increased in the long term.

    Geologic evidence of Atlantic storm frequency, which can go back over 1,000 years, also suggests that hurricane frequency does tend to wax and wane every few decades, says Elizabeth Wallace, a paleotempestologist at Rice University (US) in Houston (SN: 10/22/17).

    Wallace hunts for hurricane records in deep underwater caverns called blue holes: As a storm passes over an island beach or the barely submerged shallows, winds and waves pick up sand that then can get dumped into these caverns, forming telltale sediment deposits. Her data, she says, also suggest that “the past 150 years hasn’t been exceptional [in storm frequency], compared to the past.”

    But, Wallace notes, these deposits don’t reveal anything about whether climate change is producing more intense hurricanes. And modern observational data on changes in hurricane intensity is muddled by its own uncertainties, particularly the fact that the satellite record just isn’t that long. Still, “I liked that the study says it doesn’t necessarily provide evidence against the hypothesis” that higher sea-surface temperatures would increase hurricane intensity by adding more energy to the storm, she says.

    Kerry Emanuel, an atmospheric scientist at Massachusetts Institute of Technology (US), says the idea that storm numbers haven’t increased isn’t surprising, given the longstanding uncertainty over how global warming might alter that. But “one reservation I have about the new paper is the implication that no significant trends in Atlantic hurricane metrics [going back to 1851] implies no effect of global warming on these storms,” he says. Looking for such a long-term trend isn’t actually that meaningful, he says, as scientists wouldn’t expect to see any global warming-related hurricane trends become apparent until about the 1970s anyway, as warming has ramped up.

    Regardless of whether there are more of these storms, there’s no question that modern hurricanes have become more deadly in many ways, Vecchi says. There’s evidence that global warming has already been increasing the amount of rain from some storms, such as Hurricane Harvey in 2017, which led to widespread, devastating flooding (SN: 9/28/18). And, Vecchi says, “sea level will rise over the coming century … so [increasing] storm surge is one big hazard from hurricanes.”

    See further:
    Eos 2006

    See the full article here .

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    National Oceanic and Atmospheric Administration (US) is an agency that enriches life through science. Our reach goes from the surface of the sun to the depths of the ocean floor as we work to keep the public informed of the changing environment around them.

    From daily weather forecasts, severe storm warnings, and climate monitoring to fisheries management, coastal restoration and supporting marine commerce, NOAA’s products and services support economic vitality and affect more than one-third of America’s gross domestic product. NOAA’s dedicated scientists use cutting-edge research and high-tech instrumentation to provide citizens, planners, emergency managers and other decision makers with reliable information they need when they need it.

    The National Oceanic and Atmospheric Administration (NOAA /ˈnoʊ.ə/ NOH-ə) is an American scientific agency within the United States Department of Commerce that focuses on the conditions of the oceans, major waterways, and the atmosphere.

    NOAA warns of dangerous weather, charts seas, guides the use and protection of ocean and coastal resources and conducts research to provide the understanding and improve stewardship of the environment.

    NOAA’s specific roles include:
    Supplying Environmental Information Products. NOAA supplies to its customers and partners information pertaining to the state of the oceans and the atmosphere. This is clear through the production of weather warnings and forecasts via the National Weather Service, but NOAA’s information products extend to climate, ecosystems, and commerce as well.

    Providing Environmental Stewardship Services. NOAA is a steward of U.S. coastal and marine environments. In coordination with federal, state, local, tribal and international authorities, NOAA manages the use of these environments, regulating fisheries and marine sanctuaries as well as protecting threatened and endangered marine species.

    Conducting Applied Scientific Research. NOAA is intended to be a source of accurate and objective scientific information in the four particular areas of national and global importance identified above: ecosystems, climate, weather and water, and commerce and transportation.
    The five “fundamental activities” are:
    Monitoring and observing Earth systems with instruments and data collection networks.
    Understanding and describing Earth systems through research and analysis of that data.
    Assessing and predicting the changes in these systems over time.
    Engaging, advising, and informing the public and partner organizations with important information.
    Managing resources for the betterment of society, economy, and environment.

    National Ocean Service
    The National Ocean Service (NOS) focuses on ensuring that ocean and coastal areas are safe, healthy, and productive. NOS scientists, natural resource managers, and specialists serve America by ensuring safe and efficient marine transportation, promoting innovative solutions to protect coastal communities, and conserving marine and coastal places.

    The National Ocean Service is composed of eight program offices: the Center for Operational Oceanographic Products and Services, the Coastal Services Center, the National Centers for Coastal Ocean Science, the Office of Coast Survey, the Office of National Geodetic Survey, the Office of National Marine Sanctuaries the Office of Ocean and Coastal Resource Management and the Office of Response and Restoration.

    There are two NOS programs, namely the Mussel Watch Contaminant Monitoring Program and the NOAA Integrated Ocean Observing System (IOOS) and two staff offices, the International Program Office and the Management and Budget Office.

    National Environmental Satellite, Data, and Information Service
    The National Environmental Satellite, Data, and Information Service (NESDIS) was created by NOAA to operate and manage the US environmental satellite programs, and manage NWS data and those of other government agencies and departments. NESDIS’s National Centers for Environmental Information (NCEI) archives data collected by the NOAA, U.S. Navy, U.S. Air Force, the Federal Aviation Administration, and meteorological services around the world and comprises the Center for Weather and Climate (previously NOAA’s National Climatic Data Center), National Coastal Data Development Center (NCDDC), National Oceanographic Data Center (NODC), and the National Geophysical Data Center (NGDC)).

    In 1960, TIROS-1, NASA’s first owned and operated geostationary satellite, was launched. Since 1966, NESDIS has managed polar orbiting satellites (POES) and since 1974 it has operated geosynchronous satellites (GOES). In 1979, NOAA’s first polar-orbiting environmental satellite was launched. Current operational satellites include NOAA-15, NOAA-18, NOAA-19, GOES 13, GOES 14, GOES 15, Jason-2 and DSCOVR. In 1983, NOAA assumed operational responsibility for Landsat satellite system.

    Since May 1998, NESDIS has operated the Defense Meteorological Satellite Program (DMSP) satellites on behalf of the Air Force Weather Agency.

    New generations of satellites are developed to succeed the current polar orbiting and geosynchronous satellites, the Joint Polar Satellite System) and GOES-R, which is scheduled for launch in March 2017.
    NESDIS runs the Office of Projects, Planning, and Analysis (OPPA) formerly the Office of Systems Development, the Office of Satellite Ground Systems (formerly the Office of Satellite Operations) the Office of Satellite and Project Operations, the Center for Satellite Applications and Research (STAR)], the Joint Polar Satellite System Program Office the GOES-R Program Office, the International & Interagency Affairs Office, the Office of Space Commerce and the Office of System Architecture and Advanced Planning.

    National Marine Fisheries Service

    The National Marine Fisheries Service (NMFS), also known as NOAA Fisheries, was initiated in 1871 with a primary goal of the research, protection, management, and restoration of commercial and recreational fisheries and their habitat, and protected species. NMFS operates twelve headquarters offices, five regional offices, six fisheries science centers, and more than 20 laboratories throughout the United States and U.S. territories, which are the sites of research and management of marine resources. NMFS also operates the National Oceanic and Atmospheric Administration Fisheries Office of Law Enforcement in Silver Spring, Maryland, which is the primary site of marine resource law enforcement.

    About Princeton: Overview

    Princeton University (US) is a private Ivy League research university in Princeton, New Jersey (US). Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution. The institution moved to Newark in 1747, then to the current site nine years later. It was renamed Princeton University in 1896.

    Princeton provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences, and engineering. It offers professional degrees through the Princeton School of Public and International Affairs, the School of Engineering and Applied Science, the School of Architecture and the Bendheim Center for Finance. The university also manages the DOE’s Princeton Plasma Physics Laboratory. Princeton has the largest endowment per student in the United States.

    As of October 2020, 69 Nobel laureates, 15 Fields Medalists and 14 Turing Award laureates have been affiliated with Princeton University as alumni, faculty members or researchers. In addition, Princeton has been associated with 21 National Medal of Science winners, 5 Abel Prize winners, 5 National Humanities Medal recipients, 215 Rhodes Scholars, 139 Gates Cambridge Scholars and 137 Marshall Scholars. Two U.S. Presidents, twelve U.S. Supreme Court Justices (three of whom currently serve on the court) and numerous living billionaires and foreign heads of state are all counted among Princeton’s alumni body. Princeton has also graduated many prominent members of the U.S. Congress and the U.S. Cabinet, including eight Secretaries of State, three Secretaries of Defense and the current Chairman of the Joint Chiefs of Staff.

    Princeton University, founded as the College of New Jersey, was considered the successor of the “Log College” founded by the Reverend William Tennent at Neshaminy, PA in about 1726. New Light Presbyterians founded the College of New Jersey in 1746 in Elizabeth, New Jersey. Its purpose was to train ministers. The college was the educational and religious capital of Scottish Presbyterian America. Unlike Harvard University (US), which was originally “intensely English” with graduates taking the side of the crown during the American Revolution, Princeton was founded to meet the religious needs of the period and many of its graduates took the American side in the war. In 1754, trustees of the College of New Jersey suggested that, in recognition of Governor Jonathan Belcher’s interest, Princeton should be named as Belcher College. Belcher replied: “What a name that would be!” In 1756, the college moved its campus to Princeton, New Jersey. Its home in Princeton was Nassau Hall, named for the royal House of Orange-Nassau of William III of England.

    Following the untimely deaths of Princeton’s first five presidents, John Witherspoon became president in 1768 and remained in that post until his death in 1794. During his presidency, Witherspoon shifted the college’s focus from training ministers to preparing a new generation for secular leadership in the new American nation. To this end, he tightened academic standards and solicited investment in the college. Witherspoon’s presidency constituted a long period of stability for the college, interrupted by the American Revolution and particularly the Battle of Princeton, during which British soldiers briefly occupied Nassau Hall; American forces, led by George Washington, fired cannon on the building to rout them from it.

    In 1812, the eighth president of the College of New Jersey, Ashbel Green (1812–23), helped establish the Princeton Theological Seminary next door. The plan to extend the theological curriculum met with “enthusiastic approval on the part of the authorities at the College of New Jersey.” Today, Princeton University and Princeton Theological Seminary maintain separate institutions with ties that include services such as cross-registration and mutual library access.

    Before the construction of Stanhope Hall in 1803, Nassau Hall was the college’s sole building. The cornerstone of the building was laid on September 17, 1754. During the summer of 1783, the Continental Congress met in Nassau Hall, making Princeton the country’s capital for four months. Over the centuries and through two redesigns following major fires (1802 and 1855), Nassau Hall’s role shifted from an all-purpose building, comprising office, dormitory, library, and classroom space; to classroom space exclusively; to its present role as the administrative center of the University. The class of 1879 donated twin lion sculptures that flanked the entrance until 1911, when that same class replaced them with tigers. Nassau Hall’s bell rang after the hall’s construction; however, the fire of 1802 melted it. The bell was then recast and melted again in the fire of 1855.

    James McCosh became the college’s president in 1868 and lifted the institution out of a low period that had been brought about by the American Civil War. During his two decades of service, he overhauled the curriculum, oversaw an expansion of inquiry into the sciences, and supervised the addition of a number of buildings in the High Victorian Gothic style to the campus. McCosh Hall is named in his honor.

    In 1879, the first thesis for a Doctor of Philosophy (Ph.D.) was submitted by James F. Williamson, Class of 1877.

    In 1896, the college officially changed its name from the College of New Jersey to Princeton University to honor the town in which it resides. During this year, the college also underwent large expansion and officially became a university. In 1900, the Graduate School was established.

    In 1902, Woodrow Wilson, graduate of the Class of 1879, was elected the 13th president of the university. Under Wilson, Princeton introduced the preceptorial system in 1905, a then-unique concept in the United States that augmented the standard lecture method of teaching with a more personal form in which small groups of students, or precepts, could interact with a single instructor, or preceptor, in their field of interest.

    In 1906, the reservoir Carnegie Lake was created by Andrew Carnegie. A collection of historical photographs of the building of the lake is housed at the Seeley G. Mudd Manuscript Library on Princeton’s campus. On October 2, 1913, the Princeton University Graduate College was dedicated. In 1919 the School of Architecture was established. In 1933, Albert Einstein became a lifetime member of the Institute for Advanced Study with an office on the Princeton campus. While always independent of the university, the Institute for Advanced Study occupied offices in Jones Hall for 6 years, from its opening in 1933, until its own campus was finished and opened in 1939.

    Coeducation

    In 1969, Princeton University first admitted women as undergraduates. In 1887, the university actually maintained and staffed a sister college, Evelyn College for Women, in the town of Princeton on Evelyn and Nassau streets. It was closed after roughly a decade of operation. After abortive discussions with Sarah Lawrence College to relocate the women’s college to Princeton and merge it with the University in 1967, the administration decided to admit women and turned to the issue of transforming the school’s operations and facilities into a female-friendly campus. The administration had barely finished these plans in April 1969 when the admissions office began mailing out its acceptance letters. Its five-year coeducation plan provided $7.8 million for the development of new facilities that would eventually house and educate 650 women students at Princeton by 1974. Ultimately, 148 women, consisting of 100 freshmen and transfer students of other years, entered Princeton on September 6, 1969 amidst much media attention. Princeton enrolled its first female graduate student, Sabra Follett Meservey, as a PhD candidate in Turkish history in 1961. A handful of undergraduate women had studied at Princeton from 1963 on, spending their junior year there to study “critical languages” in which Princeton’s offerings surpassed those of their home institutions. They were considered regular students for their year on campus, but were not candidates for a Princeton degree.

    As a result of a 1979 lawsuit by Sally Frank, Princeton’s eating clubs were required to go coeducational in 1991, after Tiger Inn’s appeal to the U.S. Supreme Court was denied. In 1987, the university changed the gendered lyrics of “Old Nassau” to reflect the school’s co-educational student body. From 2009 to 2011, Princeton professor Nannerl O. Keohane chaired a committee on undergraduate women’s leadership at the university, appointed by President Shirley M. Tilghman.

    The main campus sits on about 500 acres (2.0 km^2) in Princeton. In 2011, the main campus was named by Travel+Leisure as one of the most beautiful in the United States. The James Forrestal Campus is split between nearby Plainsboro and South Brunswick. The University also owns some property in West Windsor Township. The campuses are situated about one hour from both New York City and Philadelphia.

    The first building on campus was Nassau Hall, completed in 1756 and situated on the northern edge of campus facing Nassau Street. The campus expanded steadily around Nassau Hall during the early and middle 19th century. The McCosh presidency (1868–88) saw the construction of a number of buildings in the High Victorian Gothic and Romanesque Revival styles; many of them are now gone, leaving the remaining few to appear out of place. At the end of the 19th century much of Princeton’s architecture was designed by the Cope and Stewardson firm (same architects who designed a large part of Washington University in St Louis (US) and University of Pennsylvania(US)) resulting in the Collegiate Gothic style for which it is known today. Implemented initially by William Appleton Potter and later enforced by the University’s supervising architect, Ralph Adams Cram, the Collegiate Gothic style remained the standard for all new building on the Princeton campus through 1960. A flurry of construction in the 1960s produced a number of new buildings on the south side of the main campus, many of which have been poorly received. Several prominent architects have contributed some more recent additions, including Frank Gehry (Lewis Library), I. M. Pei (Spelman Halls), Demetri Porphyrios (Whitman College, a Collegiate Gothic project), Robert Venturi and Denise Scott Brown (Frist Campus Center, among several others), and Rafael Viñoly (Carl Icahn Laboratory).

    A group of 20th-century sculptures scattered throughout the campus forms the Putnam Collection of Sculpture. It includes works by Alexander Calder (Five Disks: One Empty), Jacob Epstein (Albert Einstein), Henry Moore (Oval with Points), Isamu Noguchi (White Sun), and Pablo Picasso (Head of a Woman). Richard Serra’s The Hedgehog and The Fox is located between Peyton and Fine halls next to Princeton Stadium and the Lewis Library.

    At the southern edge of the campus is Carnegie Lake, an artificial lake named for Andrew Carnegie. Carnegie financed the lake’s construction in 1906 at the behest of a friend who was a Princeton alumnus. Carnegie hoped the opportunity to take up rowing would inspire Princeton students to forsake football, which he considered “not gentlemanly.” The Shea Rowing Center on the lake’s shore continues to serve as the headquarters for Princeton rowing.

    Cannon Green

    Buried in the ground at the center of the lawn south of Nassau Hall is the “Big Cannon,” which was left in Princeton by British troops as they fled following the Battle of Princeton. It remained in Princeton until the War of 1812, when it was taken to New Brunswick. In 1836 the cannon was returned to Princeton and placed at the eastern end of town. It was removed to the campus under cover of night by Princeton students in 1838 and buried in its current location in 1840.

    A second “Little Cannon” is buried in the lawn in front of nearby Whig Hall. This cannon, which may also have been captured in the Battle of Princeton, was stolen by students of Rutgers University in 1875. The theft ignited the Rutgers-Princeton Cannon War. A compromise between the presidents of Princeton and Rutgers ended the war and forced the return of the Little Cannon to Princeton. The protruding cannons are occasionally painted scarlet by Rutgers students who continue the traditional dispute.

    In years when the Princeton football team beats the teams of both Harvard University and Yale University in the same season, Princeton celebrates with a bonfire on Cannon Green. This occurred in 2012, ending a five-year drought. The next bonfire happened on November 24, 2013, and was broadcast live over the Internet.

    Landscape

    Princeton’s grounds were designed by Beatrix Farrand between 1912 and 1943. Her contributions were most recently recognized with the naming of a courtyard for her. Subsequent changes to the landscape were introduced by Quennell Rothschild & Partners in 2000. In 2005, Michael Van Valkenburgh was hired as the new consulting landscape architect for the campus. Lynden B. Miller was invited to work with him as Princeton’s consulting gardening architect, focusing on the 17 gardens that are distributed throughout the campus.

    Buildings

    Nassau Hall

    Nassau Hall is the oldest building on campus. Begun in 1754 and completed in 1756, it was the first seat of the New Jersey Legislature in 1776, was involved in the battle of Princeton in 1777, and was the seat of the Congress of the Confederation (and thus capitol of the United States) from June 30, 1783, to November 4, 1783. It now houses the office of the university president and other administrative offices, and remains the symbolic center of the campus. The front entrance is flanked by two bronze tigers, a gift of the Princeton Class of 1879. Commencement is held on the front lawn of Nassau Hall in good weather. In 1966, Nassau Hall was added to the National Register of Historic Places.

    Residential colleges

    Princeton has six undergraduate residential colleges, each housing approximately 500 freshmen, sophomores, some juniors and seniors, and a handful of junior and senior resident advisers. Each college consists of a set of dormitories, a dining hall, a variety of other amenities—such as study spaces, libraries, performance spaces, and darkrooms—and a collection of administrators and associated faculty. Two colleges, First College and Forbes College (formerly Woodrow Wilson College and Princeton Inn College, respectively), date to the 1970s; three others, Rockefeller, Mathey, and Butler Colleges, were created in 1983 following the Committee on Undergraduate Residential Life (CURL) report, which suggested the institution of residential colleges as a solution to an allegedly fragmented campus social life. The construction of Whitman College, the university’s sixth residential college, was completed in 2007.

    Rockefeller and Mathey are located in the northwest corner of the campus; Princeton brochures often feature their Collegiate Gothic architecture. Like most of Princeton’s Gothic buildings, they predate the residential college system and were fashioned into colleges from individual dormitories.

    First and Butler, located south of the center of the campus, were built in the 1960s. First served as an early experiment in the establishment of the residential college system. Butler, like Rockefeller and Mathey, consisted of a collection of ordinary dorms (called the “New New Quad”) before the addition of a dining hall made it a residential college. Widely disliked for their edgy modernist design, including “waffle ceilings,” the dormitories on the Butler Quad were demolished in 2007. Butler is now reopened as a four-year residential college, housing both under- and upperclassmen.

    Forbes is located on the site of the historic Princeton Inn, a gracious hotel overlooking the Princeton golf course. The Princeton Inn, originally constructed in 1924, played regular host to important symposia and gatherings of renowned scholars from both the university and the nearby Institute for Advanced Study for many years. Forbes currently houses nearly 500 undergraduates in its residential halls.

    In 2003, Princeton broke ground for a sixth college named Whitman College after its principal sponsor, Meg Whitman, who graduated from Princeton in 1977. The new dormitories were constructed in the Collegiate Gothic architectural style and were designed by architect Demetri Porphyrios. Construction finished in 2007, and Whitman College was inaugurated as Princeton’s sixth residential college that same year.

    The precursor of the present college system in America was originally proposed by university president Woodrow Wilson in the early 20th century. For over 800 years, however, the collegiate system had already existed in Britain at Cambridge and Oxford Universities. Wilson’s model was much closer to Yale University (US)’s present system, which features four-year colleges. Lacking the support of the trustees, the plan languished until 1968. That year, Wilson College was established to cap a series of alternatives to the eating clubs. Fierce debates raged before the present residential college system emerged. The plan was first attempted at Yale, but the administration was initially uninterested; an exasperated alumnus, Edward Harkness, finally paid to have the college system implemented at Harvard in the 1920s, leading to the oft-quoted aphorism that the college system is a Princeton idea that was executed at Harvard with funding from Yale.

    Princeton has one graduate residential college, known simply as the Graduate College, located beyond Forbes College at the outskirts of campus. The far-flung location of the GC was the spoil of a squabble between Woodrow Wilson and then-Graduate School Dean Andrew Fleming West. Wilson preferred a central location for the college; West wanted the graduate students as far as possible from the campus. Ultimately, West prevailed. The Graduate College is composed of a large Collegiate Gothic section crowned by Cleveland Tower, a local landmark that also houses a world-class carillon. The attached New Graduate College provides a modern contrast in architectural style.

    McCarter Theatre

    The Tony-award-winning McCarter Theatre was built by the Princeton Triangle Club, a student performance group, using club profits and a gift from Princeton University alumnus Thomas McCarter. Today, the Triangle Club performs its annual freshmen revue, fall show, and Reunions performances in McCarter. McCarter is also recognized as one of the leading regional theaters in the United States.

    Art Museum

    The Princeton University Art Museum was established in 1882 to give students direct, intimate, and sustained access to original works of art that complement and enrich instruction and research at the university. This continues to be a primary function, along with serving as a community resource and a destination for national and international visitors.

    Numbering over 92,000 objects, the collections range from ancient to contemporary art and concentrate geographically on the Mediterranean regions, Western Europe, China, the United States, and Latin America. There is a collection of Greek and Roman antiquities, including ceramics, marbles, bronzes, and Roman mosaics from faculty excavations in Antioch. Medieval Europe is represented by sculpture, metalwork, and stained glass. The collection of Western European paintings includes examples from the early Renaissance through the 19th century, with masterpieces by Monet, Cézanne, and Van Gogh, and features a growing collection of 20th-century and contemporary art, including iconic paintings such as Andy Warhol’s Blue Marilyn.

    One of the best features of the museums is its collection of Chinese art, with important holdings in bronzes, tomb figurines, painting, and calligraphy. Its collection of pre-Columbian art includes examples of Mayan art, and is commonly considered to be the most important collection of pre-Columbian art outside of Latin America. The museum has collections of old master prints and drawings and a comprehensive collection of over 27,000 original photographs. African art and Northwest Coast Indian art are also represented. The Museum also oversees the outdoor Putnam Collection of Sculpture.

    University Chapel

    The Princeton University Chapel is located on the north side of campus, near Nassau Street. It was built between 1924 and 1928, at a cost of $2.3 million [approximately $34.2 million in 2020 dollars]. Ralph Adams Cram, the University’s supervising architect, designed the chapel, which he viewed as the crown jewel for the Collegiate Gothic motif he had championed for the campus. At the time of its construction, it was the second largest university chapel in the world, after King’s College Chapel, Cambridge. It underwent a two-year, $10 million restoration campaign between 2000 and 2002.

    Measured on the exterior, the chapel is 277 feet (84 m) long, 76 feet (23 m) wide at its transepts, and 121 feet (37 m) high. The exterior is Pennsylvania sandstone, with Indiana limestone used for the trim. The interior is mostly limestone and Aquia Creek sandstone. The design evokes an English church of the Middle Ages. The extensive iconography, in stained glass, stonework, and wood carvings, has the common theme of connecting religion and scholarship.

    The Chapel seats almost 2,000. It hosts weekly ecumenical Christian services, daily Roman Catholic mass, and several annual special events.

    Murray-Dodge Hall

    Murray-Dodge Hall houses the Office of Religious Life (ORL), the Murray Dodge Theater, the Murray-Dodge Café, the Muslim Prayer Room and the Interfaith Prayer Room. The ORL houses the office of the Dean of Religious Life, Alison Boden, and a number of university chaplains, including the country’s first Hindu chaplain, Vineet Chander; and one of the country’s first Muslim chaplains, Sohaib Sultan.

    Sustainability

    Published in 2008, Princeton’s Sustainability Plan highlights three priority areas for the University’s Office of Sustainability: reduction of greenhouse gas emissions; conservation of resources; and research, education, and civic engagement. Princeton has committed to reducing its carbon dioxide emissions to 1990 levels by 2020: Energy without the purchase of offsets. The University published its first Sustainability Progress Report in November 2009. The University has adopted a green purchasing policy and recycling program that focuses on paper products, construction materials, lightbulbs, furniture, and electronics. Its dining halls have set a goal to purchase 75% sustainable food products by 2015. The student organization “Greening Princeton” seeks to encourage the University administration to adopt environmentally friendly policies on campus.

    Organization

    The Trustees of Princeton University, a 40-member board, is responsible for the overall direction of the University. It approves the operating and capital budgets, supervises the investment of the University’s endowment and oversees campus real estate and long-range physical planning. The trustees also exercise prior review and approval concerning changes in major policies, such as those in instructional programs and admission, as well as tuition and fees and the hiring of faculty members.

    With an endowment of $26.1 billion, Princeton University is among the wealthiest universities in the world. Ranked in 2010 as the third largest endowment in the United States, the university had the greatest per-student endowment in the world (over $2 million for undergraduates) in 2011. Such a significant endowment is sustained through the continued donations of its alumni and is maintained by investment advisers. Some of Princeton’s wealth is invested in its art museum, which features works by Claude Monet, Vincent van Gogh, Jackson Pollock, and Andy Warhol among other prominent artists.

    Academics

    Undergraduates fulfill general education requirements, choose among a wide variety of elective courses, and pursue departmental concentrations and interdisciplinary certificate programs. Required independent work is a hallmark of undergraduate education at Princeton. Students graduate with either the Bachelor of Arts (A.B.) or the Bachelor of Science in Engineering (B.S.E.).

    The graduate school offers advanced degrees spanning the humanities, social sciences, natural sciences, and engineering. Doctoral education is available in most disciplines. It emphasizes original and independent scholarship whereas master’s degree programs in architecture, engineering, finance, and public affairs and public policy prepare candidates for careers in public life and professional practice.

    The university has ties with the Institute for Advanced Study, Princeton Theological Seminary and the Westminster Choir College of Rider University (US).

    Undergraduate

    Undergraduate courses in the humanities are traditionally either seminars or lectures held 2 or 3 times a week with an additional discussion seminar that is called a “precept.” To graduate, all A.B. candidates must complete a senior thesis and, in most departments, one or two extensive pieces of independent research that are known as “junior papers.” Juniors in some departments, including architecture and the creative arts, complete independent projects that differ from written research papers. A.B. candidates must also fulfill a three or four semester foreign language requirement and distribution requirements (which include, for example, classes in ethics, literature and the arts, and historical analysis) with a total of 31 classes. B.S.E. candidates follow a parallel track with an emphasis on a rigorous science and math curriculum, a computer science requirement, and at least two semesters of independent research including an optional senior thesis. All B.S.E. students must complete at least 36 classes. A.B. candidates typically have more freedom in course selection than B.S.E. candidates because of the fewer number of required classes. Nonetheless, in the spirit of a liberal arts education, both enjoy a comparatively high degree of latitude in creating a self-structured curriculum.

    Undergraduates agree to adhere to an academic integrity policy called the Honor Code, established in 1893. Under the Honor Code, faculty do not proctor examinations; instead, the students proctor one another and must report any suspected violation to an Honor Committee made up of undergraduates. The Committee investigates reported violations and holds a hearing if it is warranted. An acquittal at such a hearing results in the destruction of all records of the hearing; a conviction results in the student’s suspension or expulsion. The signed pledge required by the Honor Code is so integral to students’ academic experience that the Princeton Triangle Club performs a song about it each fall. Out-of-class exercises fall under the jurisdiction of the Faculty-Student Committee on Discipline. Undergraduates are expected to sign a pledge on their written work affirming that they have not plagiarized the work.

    Graduate

    The Graduate School has about 2,600 students in 42 academic departments and programs in social sciences; engineering; natural sciences; and humanities. These departments include the Department of Psychology; Department of History; and Department of Economics.

    In 2017–2018, it received nearly 11,000 applications for admission and accepted around 1,000 applicants. The University also awarded 319 Ph.D. degrees and 170 final master’s degrees. Princeton has no medical school, law school, business school, or school of education. (A short-lived Princeton Law School folded in 1852.) It offers professional graduate degrees in architecture; engineering; finance and public policy- the last through the Princeton School of Public and International Affairs founded in 1930 as the School of Public and International Affairs and renamed in 1948 after university president (and U.S. president) Woodrow Wilson, and most recently renamed in 2020.

    Libraries

    The Princeton University Library system houses over eleven million holdings including seven million bound volumes. The main university library, Firestone Library, which houses almost four million volumes, is one of the largest university libraries in the world. Additionally, it is among the largest “open stack” libraries in existence. Its collections include the autographed manuscript of F. Scott Fitzgerald’s The Great Gatsby and George F. Kennan’s Long Telegram. In addition to Firestone library, specialized libraries exist for architecture, art and archaeology, East Asian studies, engineering, music, public and international affairs, public policy and university archives, and the sciences. In an effort to expand access, these libraries also subscribe to thousands of electronic resources.

    Institutes

    High Meadows Environmental Institute

    The High Meadows Environmental Institute is an “interdisciplinary center of environmental research, education, and outreach” at the university. The institute was started in 1994. About 90 faculty members at Princeton University are affiliated with it.

    The High Meadows Environmental Institute has the following research centers:

    Carbon Mitigation Initiative (CMI): This is a 15-year-long partnership between PEI and British Petroleum with the goal of finding solutions to problems related to climate change. The Stabilization Wedge Game has been created as part of this initiative.
    Center for BioComplexity (CBC)
    Cooperative Institute for Climate Science (CICS): This is a collaboration with the National Oceanographic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory.
    Energy Systems Analysis Group
    Grand Challenges

    Princeton Plasma Physics Laboratory

    The Princeton Plasma Physics Laboratory, PPPL, was founded in 1951 as Project Matterhorn, a top secret cold war project aimed at achieving controlled nuclear fusion. Princeton astrophysics professor Lyman Spitzer became the first director of the project and remained director until the lab’s declassification in 1961 when it received its current name.

    PPPL currently houses approximately half of the graduate astrophysics department, the Princeton Program in Plasma Physics. The lab is also home to the Harold P. Furth Plasma Physics Library. The library contains all declassified Project Matterhorn documents, included the first design sketch of a stellarator by Lyman Spitzer.

    Princeton is one of five US universities to have and to operate a Department of Energy(US) national laboratory.

    Student life and culture

    University housing is guaranteed to all undergraduates for all four years. More than 98% of students live on campus in dormitories. Freshmen and sophomores must live in residential colleges, while juniors and seniors typically live in designated upperclassman dormitories. The actual dormitories are comparable, but only residential colleges have dining halls. Nonetheless, any undergraduate may purchase a meal plan and eat in a residential college dining hall. Recently, upperclassmen have been given the option of remaining in their college for all four years. Juniors and seniors also have the option of living off-campus, but high rent in the Princeton area encourages almost all students to live in university housing. Undergraduate social life revolves around the residential colleges and a number of coeducational eating clubs, which students may choose to join in the spring of their sophomore year. Eating clubs, which are not officially affiliated with the university, serve as dining halls and communal spaces for their members and also host social events throughout the academic year.

    Princeton’s six residential colleges host a variety of social events and activities, guest speakers, and trips. The residential colleges also sponsor trips to New York for undergraduates to see ballets, operas, Broadway shows, sports events, and other activities. The eating clubs, located on Prospect Avenue, are co-ed organizations for upperclassmen. Most upperclassmen eat their meals at one of the eleven eating clubs. Additionally, the clubs serve as evening and weekend social venues for members and guests. The eleven clubs are Cannon; Cap and Gown; Charter; Cloister; Colonial; Cottage; Ivy; Quadrangle; Terrace; Tiger; and Tower.

    Princeton hosts two Model United Nations conferences, PMUNC in the fall for high school students and PDI in the spring for college students. It also hosts the Princeton Invitational Speech and Debate tournament each year at the end of November. Princeton also runs Princeton Model Congress, an event that is held once a year in mid-November. The four-day conference has high school students from around the country as participants.

    Although the school’s admissions policy is need-blind, Princeton, based on the proportion of students who receive Pell Grants, was ranked as a school with little economic diversity among all national universities ranked by U.S. News & World Report. While Pell figures are widely used as a gauge of the number of low-income undergraduates on a given campus, the rankings article cautions “the proportion of students on Pell Grants isn’t a perfect measure of an institution’s efforts to achieve economic diversity,” but goes on to say that “still, many experts say that Pell figures are the best available gauge of how many low-income undergrads there are on a given campus.”

    TigerTrends is a university-based student run fashion, arts, and lifestyle magazine.

    Demographics

    Princeton has made significant progress in expanding the diversity of its student body in recent years. The 2019 freshman class was one of the most diverse in the school’s history, with 61% of students identifying as students of color. Undergraduate and master’s students were 51% male and 49% female for the 2018–19 academic year.

    The median family income of Princeton students is $186,100, with 57% of students coming from the top 10% highest-earning families and 14% from the bottom 60%.

    In 1999, 10% of the student body was Jewish, a percentage lower than those at other Ivy League schools. Sixteen percent of the student body was Jewish in 1985; the number decreased by 40% from 1985 to 1999. This decline prompted The Daily Princetonian to write a series of articles on the decline and its reasons. Caroline C. Pam of The New York Observer wrote that Princeton was “long dogged by a reputation for anti-Semitism” and that this history as well as Princeton’s elite status caused the university and its community to feel sensitivity towards the decrease of Jewish students. At the time many Jewish students at Princeton dated Jewish students at the University of Pennsylvania in Philadelphia because they perceived Princeton as an environment where it was difficult to find romantic prospects; Pam stated that there was a theory that the dating issues were a cause of the decline in Jewish students.

    In 1981, the population of African Americans at Princeton University made up less than 10%. Bruce M. Wright was admitted into the university in 1936 as the first African American, however, his admission was a mistake and when he got to campus he was asked to leave. Three years later Wright asked the dean for an explanation on his dismissal and the dean suggested to him that “a member of your race might feel very much alone” at Princeton University.

    Traditions

    Princeton enjoys a wide variety of campus traditions, some of which, like the Clapper Theft and Nude Olympics, have faded into history:

    Arch Sings – Late-night concerts that feature one or several of Princeton’s undergraduate a cappella groups, such as the Princeton Nassoons; Princeton Tigertones; Princeton Footnotes; Princeton Roaring 20; and The Princeton Wildcats. The free concerts take place in one of the larger arches on campus. Most are held in Blair Arch or Class of 1879 Arch.

    Bonfire – Ceremonial bonfire that takes place in Cannon Green behind Nassau Hall. It is held only if Princeton beats both Harvard University and Yale University at football in the same season. The most recent bonfire was lighted on November 18, 2018.

    Bicker – Selection process for new members that is employed by selective eating clubs. Prospective members, or bickerees, are required to perform a variety of activities at the request of current members.

    Cane Spree – An athletic competition between freshmen and sophomores that is held in the fall. The event centers on cane wrestling, where a freshman and a sophomore will grapple for control of a cane. This commemorates a time in the 1870s when sophomores, angry with the freshmen who strutted around with fancy canes, stole all of the canes from the freshmen, hitting them with their own canes in the process.

    The Clapper or Clapper Theft – The act of climbing to the top of Nassau Hall to steal the bell clapper, which rings to signal the start of classes on the first day of the school year. For safety reasons, the clapper has been removed permanently.

    Class Jackets (Beer Jackets) – Each graduating class designs a Class Jacket that features its class year. The artwork is almost invariably dominated by the school colors and tiger motifs.

    Communiversity – An annual street fair with performances, arts and crafts, and other activities that attempts to foster interaction between the university community and the residents of Princeton.

    Dean’s Date – The Tuesday at the end of each semester when all written work is due. This day signals the end of reading period and the beginning of final examinations. Traditionally, undergraduates gather outside McCosh Hall before the 5:00 PM deadline to cheer on fellow students who have left their work to the very last minute.

    FitzRandolph Gates – At the end of Princeton’s graduation ceremony, the new graduates process out through the main gate of the university as a symbol of the fact that they are leaving college. According to tradition, anyone who exits campus through the FitzRandolph Gates before his or her own graduation date will not graduate.

    Holder Howl – The midnight before Dean’s Date, students from Holder Hall and elsewhere gather in the Holder courtyard and take part in a minute-long, communal primal scream to vent frustration from studying with impromptu, late night noise making.

    Houseparties – Formal parties that are held simultaneously by all of the eating clubs at the end of the spring term.

    Ivy stones – Class memorial stones placed on the exterior walls of academic buildings around the campus.

    Lawnparties – Parties that feature live bands that are held simultaneously by all of the eating clubs at the start of classes and at the conclusion of the academic year.

    Princeton Locomotive – Traditional cheer in use since the 1890s. It is commonly heard at Opening Exercises in the fall as alumni and current students welcome the freshman class, as well as the P-rade in the spring at Princeton Reunions. The cheer starts slowly and picks up speed, and includes the sounds heard at a fireworks show.

    Hip! Hip!
    Rah, Rah, Rah,
    Tiger, Tiger, Tiger,
    Sis, Sis, Sis,
    Boom, Boom, Boom, Ah!
    Princeton! Princeton! Princeton!

    Or if a class is being celebrated, the last line consists of the class year repeated three times, e.g. “Eighty-eight! Eighty-eight! Eighty-eight!”

    Newman’s Day – Students attempt to drink 24 beers in the 24 hours of April 24. According to The New York Times, “the day got its name from an apocryphal quote attributed to Paul Newman: ’24 beers in a case, 24 hours in a day. Coincidence? I think not.'” Newman had spoken out against the tradition, however.

    Nude Olympics – Annual nude and partially nude frolic in Holder Courtyard that takes place during the first snow of the winter. Started in the early 1970s, the Nude Olympics went co-educational in 1979 and gained much notoriety with the American press. For safety reasons, the administration banned the Olympics in 2000 to the chagrin of students.

    Prospect 11 – The act of drinking a beer at all 11 eating clubs in a single night.

    P-rade – Traditional parade of alumni and their families. They process through campus by class year during Reunions.

    Reunions – Massive annual gathering of alumni held the weekend before graduation.

    Athletics

    Princeton supports organized athletics at three levels: varsity intercollegiate, club intercollegiate, and intramural. It also provides “a variety of physical education and recreational programs” for members of the Princeton community. According to the athletics program’s mission statement, Princeton aims for its students who participate in athletics to be “‘student athletes’ in the fullest sense of the phrase. Most undergraduates participate in athletics at some level.

    Princeton’s colors are orange and black. The school’s athletes are known as Tigers, and the mascot is a tiger. The Princeton administration considered naming the mascot in 2007, but the effort was dropped in the face of alumni opposition.

    Varsity

    Princeton is an NCAA Division I school. Its athletic conference is the Ivy League. Princeton hosts 38 men’s and women’s varsity sports. The largest varsity sport is rowing, with almost 150 athletes.

    Princeton’s football team has a long and storied history. Princeton played against Rutgers University in the first intercollegiate football game in the U.S. on Nov 6, 1869. By a score of 6–4, Rutgers won the game, which was played by rules similar to modern rugby. Today Princeton is a member of the Football Championship Subdivision of NCAA Division I. As of the end of the 2010 season, Princeton had won 26 national football championships, more than any other school.

    Club and intramural

    In addition to varsity sports, Princeton hosts about 35 club sports teams. Princeton’s rugby team is organized as a club sport. Princeton’s sailing team is also a club sport, though it competes at the varsity level in the MAISA conference of the Inter-Collegiate Sailing Association.

    Each year, nearly 300 teams participate in intramural sports at Princeton. Intramurals are open to members of Princeton’s faculty, staff, and students, though a team representing a residential college or eating club must consist only of members of that college or club. Several leagues with differing levels of competitiveness are available.

    Songs

    Notable among a number of songs commonly played and sung at various events such as commencement, convocation, and athletic games is Princeton Cannon Song, the Princeton University fight song.

    Bob Dylan wrote Day of The Locusts (for his 1970 album New Morning) about his experience of receiving an honorary doctorate from the University. It is a reference to the negative experience he had and it mentions the Brood X cicada infestation Princeton experienced that June 1970.

    “Old Nassau”

    Old Nassau has been Princeton University’s anthem since 1859. Its words were written that year by a freshman, Harlan Page Peck, and published in the March issue of the Nassau Literary Review (the oldest student publication at Princeton and also the second oldest undergraduate literary magazine in the country). The words and music appeared together for the first time in Songs of Old Nassau, published in April 1859. Before the Langlotz tune was written, the song was sung to Auld Lang Syne’s melody, which also fits.

    However, Old Nassau does not only refer to the university’s anthem. It can also refer to Nassau Hall, the building that was built in 1756 and named after William III of the House of Orange-Nassau. When built, it was the largest college building in North America. It served briefly as the capitol of the United States when the Continental Congress convened there in the summer of 1783. By metonymy, the term can refer to the university as a whole. Finally, it can also refer to a chemical reaction that is dubbed “Old Nassau reaction” because the solution turns orange and then black.
    Princeton Shield

     
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