Tagged: Eos Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 7:23 am on February 3, 2023 Permalink | Reply
    Tags: " 'Hot Jupiter' Is in a Possible Death Spiral", , , , , , Eos, , , ,   

    From Princeton University And From The Harvard-Smithsonian Center for Astrophysics Via “Eos” : ” ‘Hot Jupiter’ Is in a Possible Death Spiral” 

    Princeton University

    From Princeton University


    From The Harvard-Smithsonian Center for Astrophysics


    Eos news bloc




    Damond Benningfield

    Kepler-1658b is spiraling closer to its star in this artist’s rendering. Credit: Gabriel Perez Diaz/Instituto de Astrofísica de Canarias.

    A distant planet is in a death spiral and is poised to be engulfed by its parent star.

    Kepler-1658b is the first inspiraling planet discovered around an “evolved” star—one that has moved out of its prime life. The star—Kepler-1658—is about 1.5 times the mass of our Sun and has expanded to almost 3 times the Sun’s diameter in its late stages of life, earning it the designation of subgiant.

    Should Kepler-1658b maintain its current path, it will meet its fate in about 2.5 million years.

    As the complicated discovery of the planet and its star has shown, however, nothing is certain. “It’s a very confounding system,” said Ashley Chontos, a postdoctoral fellow at Princeton University and a member of the team that discovered the planet’s shrinking orbit.

    Kepler-1658b was the first exoplanet discovered by the Kepler space telescope, which found thousands of bodies over its lifetime using the transit technique. The telescope measured tiny dips in a star’s brightness when a planet crossed in front of it.

    Kepler stares into a galaxy filled with its exoplanet discoveries in this illustration commissioned for the space telescope’s retirement. Credit: NASA.

    Early in its mission, Kepler recorded such dips from Kepler-1658. However, astronomers had initially cataloged the star as belonging to the main sequence—stars like the Sun that are still burning the hydrogen in their cores. Researchers expected the star to be much smaller than it is, so the initial transit signals “didn’t make sense,” said Shreyas Vissapragada, a postdoctoral researcher at the Harvard-Smithsonian Center for Astrophysics and lead author of the new study [The Astrophysical Journal Letters (below)]. The transit indicated a planet roughly the size of Neptune, our solar system’s third-largest planet. However, the system also produced a secondary eclipse as the planet passed behind the star. At Kepler 1658’s distance, a Neptune-sized planet wouldn’t be bright enough to see, so there would be no evidence of the secondary eclipse.

    Kepler-1658b was discarded as a false positive and forgotten about.

    That is, until Chontos began looking at vibrations on the surfaces of stars in the Kepler catalog. Because the telescope kept a constant eye on the stars in its field of view, recording brightness levels every half hour or less, it detected “jiggles” caused by sound waves reverberating through the stars. Piecing together the vibrations—a technique known as asteroseismology—revealed details about the stars’ interiors.

    In the case of Kepler-1658, they showed that the star was much farther along in life than expected and hence about 3 times bigger. That meant the transiting planet was 3 times larger as well, making it big enough and bright enough to contribute to the system’s overall brightness when it wasn’t eclipsed by the star. “Suddenly, a close-in hot Jupiter made sense,” Chontos said. “That discovery [The Astronomical Journal (below)] was completely accidental.”

    A hot Jupiter is a massive planet comparable to Jupiter—the giant of our own solar system—that orbits so close to its star that it is extremely hot. In this case, Kepler-1658b is about the size of Jupiter, but with almost 6 times its mass. “Even the combined masses of all the planets in [our] solar system don’t add up to that,” Chontos said. The planet orbits its star once every 3.85 Earth days, compared with an 88-day period for Mercury, the Sun’s closest planet.

    Changing a Planetary Clock

    Kepler observed the system for about 4 years, so it obtained a pretty good, but not perfect, measurement of the orbital period. It appeared to show that Kepler-1658b followed a steady path around the star.

    At the same time Chontos was studying the system’s vibrations, though, Vissapragada was conducting his own observations. One night, in fact, he and Chontos bumped into each other during runs at the 200-inch Hale Telescope at Palomar Observatory, where both were looking at the system.

    Vissapragada obtained data from two Hale sessions plus three monthlong sets of observations by the Transiting Exoplanet Survey Satellite (TESS), a space telescope designed to discover and study exoplanets.

    When combined with the earlier Kepler data, the data provided a 13-year baseline of observations.

    “They showed that the clock had changed—the transits were happening measurably earlier than they were predicted to occur,” Vissapragada said. Kepler-1658b’s orbital period was decreasing by 131 milliseconds per year (plus or minus about 20 milliseconds), suggesting the planet will spiral into the star in about 2.5 million years.

    The shrinking orbit is probably the result of tidal effects. “We think we know the total energy in the system,” Chontos said. “The planet is depositing energy in the star, causing it to rotate faster and the planet’s orbit to shrink.” A small amount of the system’s total energy could be dissipated in the planet as well, explaining some minor oddities in its orbit, Vissapragada added.

    Ruling Out the Alternatives

    An inspiral isn’t the only possible explanation for the apparent change in orbital period, however. The timing could appear to change if the system were moving toward us, for example. By measuring the system’s radial velocity—its motion toward or away from us—the team ruled out that possibility.

    It also ruled out the possibility that we see only part of the orbit’s precession period—a “wobble” in the orbit. “We think we’ve ruled out all other probable causes,” said Vissapragada.

    “The evidence for inspiraling planets is plausible, and this paper presents good arguments for this being the case for this planet,” said Girish Duvvuri, a graduate research assistant at the University of Colorado-Boulder who has studied the demise of exoplanets but was not involved in this project. “While I can’t say they’ve exhausted all alternative hypotheses, they covered everything I can think of.”

    Even so, no one can say the fate of Kepler-1658b is sealed. The process of orbital evolution for planets around evolving stars is poorly understood, so several outcomes are possible.

    “The whole dissipation process is very complicated,” Chontos said. “It involves the obliquity, eccentricity, distance—all these different aspects of the orbit that can change over time. While it’s going inward now, there’s nothing to say that the orbit won’t circularize and its migration will stop—just halt. At some point, the planet might even migrate outward. But right now, that’s all just speculation.”

    The astronomers hope to narrow down the possibilities with additional observations of the system by TESS and other ground- and space-based telescopes. And they said that finding similar systems will help as well.

    “We need to look at more of these systems to pin down exactly how that evolution works,” Vissapragada said. “TESS should give us a lot more examples over the next decade, so we’ll have a fairly large sample to see if this mechanism is common.”

    The Astrophysical Journal Letters 2022
    The Astronomical Journal 2019
    See the science papers 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. Use “Reply”.


    Please help promote STEM in your local schools.

    Stem Education Coalition

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

    The Harvard-Smithsonian Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

    Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory, one of NASA’s Great Observatories.

    GMT Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s NSF NOIRLab NOAO Las Campanas Observatory(CL) some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

    National Aeronautics and Space Administration Chandra X-ray telescope.

    Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System, for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

    The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University and the Smithsonian Institution. This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

    History of the Smithsonian Astrophysical Observatory (SAO)

    Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

    In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

    With the creation of National Aeronautics and Space Administration the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

    History of Harvard College Observatory (HCO)

    Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

    Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

    Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

    Joint history as the Center for Astrophysics (CfA)

    The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

    This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with University of California- Berkeley, was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

    Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world.

    Harvard Smithsonian Center for Astrophysics Fred Lawrence Whipple Observatory located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization] (EU)/National Aeronautics and Space Administration SOHO satellite. Launched in 1995.

    National Aeronautics Space Agency NASA Kepler Space Telescope

    CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

    The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

    The CfA Today

    Research at the CfA

    Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

    The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

    CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawai’i, Altitude 4,205 m (13,796 ft).

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including The University of Chicago ; The University of California-Berkeley ; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; The University of Colorado- Boulder; McGill (CA) University, The University of Illinois, Urbana-Champaign; The University of California- Davis; Ludwig Maximilians Universität München(DE); DOE’s Argonne National Laboratory; and The National Institute for Standards and Technology.

    Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker. The Johns Hopkins University Applied Physics Lab.

    National Aeronautics and Space Administration Solar Dynamics Observatory.

    Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構] (JP)/National Aeronautics and Space Administration HINODE spacecraft.

    SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

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

    The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

    In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

    About Princeton: Overview

    Princeton University 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 , 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.


    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 and University of Pennsylvania) 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.


    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.


    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 University of Cambridge (UK) and University of Oxford (UK). Wilson’s model was much closer to Yale University’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.


    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.


    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.


    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 .


    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.


    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.


    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.


    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 DOE’s Princeton Plasma Physics Laboratory 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 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.


    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.


    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.


    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.


    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.


    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

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 4:10 pm on January 27, 2023 Permalink | Reply
    Tags: "What’s Up at the Bottom of the Ocean?", , , Eos, From isotopes to oil spills and sand mining to SMART cables an array of science is grounded on the seafloor., , Our changing climate and the crucial nexus of ocean and atmosphere are driving scientists to collate and curate a centralized database of seawater oxygen isotope data., The seafloor is not as serene as it seems. In fact it’s a busy flexible hub of scientific activity.   

    From “Eos” : “What’s Up at the Bottom of the Ocean?” 

    Eos news bloc

    From “Eos”



    Caryl-Sue Micalizio

    From isotopes to oil spills and sand mining to SMART cables an array of science is grounded on the seafloor.

    Sand drains from an unnamed river into Murchison Sound close to Qaanaaq in northwestern Greenland. Credit: Nicolaj Krog Larsen.


    The seafloor is not as serene as it seems. In fact it’s a busy flexible hub of scientific activity.

    Our changing climate and the crucial nexus of ocean and atmosphere are driving scientists to collate and curate a centralized database of seawater oxygen isotope data. Such isotopes can inform us about processes related to ocean cir­culation, riverine input, ocean-atmosphere water exchange, and continental ice sheet volume on timescales spanning glacial–interglacial periods and longer, write Kristine DeLong, Alyssa Atwood, Andrea Moore, and Sara Sanchez, but efforts to create a machine-readable, metadata-rich database con­sistent with findability, accessibility, interoperability, and reusability (FAIR) standards has been a challenge for more than 30 years. Still a work in progress, the new database has already revealed discrepancies between tracked and modeled estimates of coral-derived isotope variability, as well as enor­mous swaths of the ocean that lack any isotope data at all. Read Clues from the Sea Paint a Picture of Earth’s Water Cycle.

    Far from having a lack of data, scientists tracking the origin of a 2021 oil spill in the eastern Mediterranean had to grapple with the (literal) chaos of eddies, currents, multinational ship traffic, and satellite-derived radar imagery. Using innovative mathematics to better resolve geometry in the ocean’s dynamical systems, they developed a model “to keep turbu­lence from serving as a cover for environmental pollution.” Learn more about Seeing Through Turbulence to Track Oil Spills in the Ocean from Guillermo García-Sánchez, Ana M. Mancho, Antonio G. Ramos, Josep Coca, and Stephen Wiggins.

    Lack of data, arrays of data: In Grains of Sand: Too Much and Never Enough, Alka Tripathy- Lang explores sand mining and its discontents. Sand is second only to water as an exploited natural resource (used in everything from concrete to smartphone screens), but scientists, engineers, and industry officials are quick to note that the sands that anchor seafloors and deserts are not created equal: “The crisis that exists around sand is mostly a crisis of sand sus­tainability, not of availability,” said Daniel Franks of Australia’s Sustainable Minerals Insti­tute.

    Seafloor stories also appeared at AGU’s Fall Meeting 2022. Some scientists are investigat­ing how benthic amphipods are providing clues to marine mercury pollution (In the Deepest Ocean Reaches, a Potent Pollutant Comes to Rest), whereas others are considering how the subsea cables that transmit cat videos and financial transactions could also contain temperature, pressure, and seismic sensors (Making Underwater Cables SMART with Sen­sors). Finally, we are reminded that the seafloor can define regions millions of years after the actual sea has disappeared, as we learn in A Mysterious Dome Reveals Clues to Aus­tralia’s Miocene History.

    So what’s up at the bottom of the ocean? A lot of science, and Eos is happy to delve deep.

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 2:58 pm on January 26, 2023 Permalink | Reply
    Tags: "Quantifying the Potential of Forestation for Carbon Storage", , , , , , Eos   

    From “Eos” : “Quantifying the Potential of Forestation for Carbon Storage” 

    Eos news bloc

    From “Eos”



    Benjamin Sulman

    Current and potential forest areas in the study area of southern China. “New forests” (orange) were forested between 2002 and 2017, while “Old forests” (green) existed prior to 2002. “Potential forests” (blue) are not currently forested but were identified by the analysis as suitable for forest growth. Credit: Zhang et al. [2022], Figure 1

    Large-scale forest planting projects have been proposed as a carbon sequestration strategy for mitigating anthropogenic climate change. In southern China, tree-planting initiatives over recent decades have significantly expanded forested areas and sequestered substantial amounts of carbon in tree biomass. Understanding both the historical carbon sequestration and the potential for future carbon storage through forestation is important for developing climate change mitigation strategies.

    Zhang et al. [2022] use a combination of data synthesis, remote sensing, and machine learning approaches to estimate the historical trajectory and the potential carbon storage capacity of forests in southern China. They find that regional forest carbon storage has increased over the 15-year study period, signifying successful carbon sequestration, and they identify opportunities for further increasing carbon density in forestation projects. However, they also find that forests in the region have already achieved more than 73% of their carbon storage capacity, indicating that afforestation alone will ultimately face limits as a carbon sequestration strategy.

    Earth’s Future

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 10:52 am on January 17, 2023 Permalink | Reply
    Tags: "Deep-Sea Pressure Crushes Carbon Cycling", , , , Eos, , Instead of bringing deep-sea samples to the surface for experiments scientists bring their experiments to the deep sea., Knowing the rate that microbes break down organic carbon in the deep sea is really important., , , Microbes are by far the main contributors to carbon processing in the deep ocean., Microbial communities consumed carbon about one third as quickly at 4000 meters deep as at the surface., New evidence suggests that the extreme pressures of the deep sea slow down microbial carbon degradation., The extreme pressure in the deep sea stifles microbes’ appetite for organic carbon. This finding could have important implications for carbon budgets and geoengineering.   

    From “Eos” : “Deep-Sea Pressure Crushes Carbon Cycling” 

    Eos news bloc

    From “Eos”



    Elise Cutts

    The extreme pressure in the deep sea stifles microbes’ appetite for organic carbon. This finding could have important implications for carbon budgets and geoengineering.

    Scientists used a clever device to measure deep-sea organic carbon degradation rates underwater, avoiding the need to keep samples in finicky and expensive pressure chambers. Credit: Chie Amano.

    When the research submarine Alvin sank off the coast of Massachusetts in 1968, it took the crew’s lunch with it. Sandwiches wrapped in wax paper, a few thermoses of broth, and an apple or two came to rest with the legendary exploration vessel. And to the shock of the scientists who later returned to recover the wreck, there they remained—practically unspoiled despite sitting more than a kilometer below the surface for nearly a year.

    A sandwich left out on your countertop or casually thrown into the sea would be lucky to last more than a day or two before going bad or getting gobbled up. So why didn’t something eat the Alvin crew’s lunch?

    New evidence suggests that the extreme pressures of the deep sea slow down microbial carbon degradation, the process responsible for spoiling sandwiches and recycling organic carbon into carbon dioxide, a critical step in the carbon cycle. The research team behind the new study says that their findings could have important implications for carbon budgets, which are used in climate models, and future geoengineering strategies that propose storing excess carbon on the seafloor. The results were published in Nature Geoscience [below].

    Fig. 1: In situ bulk leucine incorporation rates normalized to rates obtained at atmospheric pressure conditions.
    Symbols correspond to the different research expeditions (Extended Data Fig. 1). Regression equation is a power law function: Pinsitu = 494z^−0.321 (n = 56, number of samples incubated at in situ), where Pinsitu is the percentage of in situ leucine incorporation rate normalized to mean leucine incorporation rate under atmospheric pressure (Atm.) and z is depth (m). Shaded area indicates 95% confidence interval for the regression. Note that the data points at 0 m (n = 4) correspond to instrumental tests in which epi- to bathypelagic waters were incubated with the ISMI under atmospheric pressure conditions and compared with bottle incubations used for atmospheric pressure incubations to assess the potential bias associated with the instrument. These points are excluded from calculating the regression line.

    Fig. 2: Cell-specific leucine uptake by prokaryotes.
    [a], Distribution of cell-specific leucine uptake expressed as the percentage of total active cell counts (upper panels) and the percentage of total uptake (lower panels). Water was collected at meso- and bathypelagic depths and incubated under in situ and atmospheric pressure (Atm.) conditions (Supplementary Tables 1 and 2). [b], A microscopic view of a bathypelagic sample (2,000 m) collected in the Atlantic and incubated under atmospheric pressure conditions. Black halos around the cells are silver grains corresponding to their activities. The highly active cells (>0.5 amol Leu cell−1 d−1, indicated by arrows) were barely found in in situ pressure incubations. Typical low-activity cells in the bathypelagic depths are indicated by circles. Green fluorescence, EUB338 probe mix; light blue, DAPI-stained cells. Scale bar, 5 µm. [c], Leucine uptake by taxonomical groups: S11, SAR11 clade; S202, SAR202 clade; S406, SAR406 clade; Alt, Alteromonas; Cf, Bacteroidetes; Cren, Thaumarchaeota; Eury, Euryarchaeota. The grey line connects the same location and depth between in situ and Atm. samples representing the change in leucine uptake beween the two incubation conditions.

    Fig. 3: Depth-related changes in the metaproteome of three abundant deep-sea bacterial taxa.
    [a], Venn diagrams indicating the number of shared and unique up- and down-regulated proteins among Alteromonas, Bacteroidetes and SAR202 of meso- versus epipelagic layers, bathy- versus mesopelagic layers and bathy- versus epipelagic layers. Numbers indicate the protein abundance. Epi, epipelagic; Meso, mesopelagic; Bathy, bathypelagic waters. [b], Comparison of expressed proteins produced by Alteromonas, Bacteroidetes and SAR202. Significance of the change between depth layers is indicated by different colours: not significant (NS), P ≥ 0.05; up-regulated proteins (Up), P < 0.05 and log2 fold change ≥1; down-regulated proteins (Down), P < 0.05 and log2 fold change ≤ −1. The P values are shown in Supplementary Data 1.

    Challenging Deeps

    For decades, scientists have wondered whether microbial carbon degradation is suppressed in the deep sea. But answering this seemingly simple question has proven challenging.

    Shallow-water microbes continually fall into the deep ocean from the sunlit surface. These unwilling interlopers would presumably break down carbon more slowly at depth because they have not adapted to the pressure.

    “These microbes survive, barely, in the deep sea. But they are not feeling really comfortable there,” said marine microbiologist Gerhard Herndl of the University of Vienna.

    But other microbes don’t mind pressure much at all. Some will even die if they’re decompressed. Some of these pressure-loving piezophiles seem to have hearty appetites for organic carbon, leading some scientists to think that microbial activity in the deep sea could actually be rather high—though it’s possible that when scientists sample these communities, “we’re just isolating the ‘weeds’ that grow quickly,” said marine microbiologist Douglas Bartlett of the Scripps Institution of Oceanography, who was not involved in the new study.

    Complicating everything further is the enormous technical challenge of working in the deep. Keeping a deep-sea sample under pressure after bringing it to the surface requires a tough titanium chamber that can tolerate pressure differences hundreds of times greater than that between the inside and outside of the International Space Station.

    “That’s really hard engineering to do,” Bartlett said. So scientists have mostly measured deep-sea carbon degradation rates in depressurized samples brought up to the surface.

    But without a way to make measurements under natural deep-sea conditions—pressure and all—it’s impossible to know whether the observations researchers have made in decompressed samples reflect what’s going on in the depths.

    Getting to the Bottom of It

    After years of trying to get pressure chambers to work, Herndl and his colleagues took a different approach; instead of bringing deep-sea samples to the surface for experiments, they’d bring their experiments to the deep sea.

    Previously, researchers in Japan worked with Herndl’s group to develop a device that can be lowered from a ship to make measurements under water. The device takes a water sample, performs an experiment, and then adds a special fluid into the sample to “fix” it, preserving microbes exactly as they were in the deep sea. Then the sample is brought to the surface for measurements.

    In the Pacific, Atlantic, and Southern Oceans, experiments with this device revealed that as a whole, microbial communities consumed carbon about one third as quickly at 4000 meters deep as at the surface.

    Roughly 85% of microbes consumed carbon at about the same rate regardless of depth, and only about 5% of the microbes in seawater samples were pressure-loving piezophiles. The remaining 10% of microbes were pressure hating. These communities “respond tremendously when you release them from pressure,” gobbling up carbon much faster than they do in the deep sea, Herndl said. Because these organisms are much more active at sea surface pressure, previous estimates of the carbon degradation rates of deep-sea microbial communities were “really grossly overestimated,” he added.

    Carbon Budgeting

    The discovery could have important implications for geoengineering and for the carbon budgets that scientists use to build climate models.

    “One of the issues of our time now is what to do about climate impacts,” Bartlett said. Pumping carbon dioxide into the atmosphere drives climate change, prompting some to devise creative carbon storage solutions. “People consider ways to bring more particulate organic carbon into the deep ocean to bury it and to sequester that carbon,” so knowing the rate that microbes break down organic carbon in the deep sea “is really important,” he said.

    With respect to carbon budgeting, Herndl added, the discovery resolves a long-standing problem. Previous estimates of deep-ocean carbon degradation rates found a troubling mismatch: The supply of organic material sinking down from the surface seemed far smaller than deep-sea microbes’ appetite for that carbon. If the budgets really are misbalanced, “then apparently we don’t understand how the deep ocean works,” Herndl said.

    But the new, lower carbon demand measured in this study lines up neatly with supply. The mismatch looks like it was simply a matter of overestimating carbon degradation rates in depressurized samples, Herndl and Bartlett said.

    “It seems like that was the magic bullet—the solution that had eluded microbial oceanographers all these years,” Bartlett said, “not [measuring] microbial activity under the actual deep-sea conditions.”

    “Microbes are by far the main contributors to carbon processing in the deep ocean,” Herndl said. “So it makes a difference when you [calculate] a global carbon budget…it makes a difference whether you estimate microbial activity in the deep correctly or not.”

    Science paper:
    Nature Geoscience

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 11:35 am on December 27, 2022 Permalink | Reply
    Tags: "The Great Unconformity or Great Unconformities?", , Beneath Earth’s surface the deeper the rock is the hotter it is., Earth history, , , Either nondeposition or erosion (or both) lurking in the boundary between the rock strata., Eos, , , Some scientists think the Great Unconformity was caused by a single erosion event. Recent work suggests the phenomenon might not be so simple.,   

    From “Eos” : “The ‘Great Unconformity’ or ‘Great Unconformities’?” 

    Eos news bloc

    From “Eos”



    Alka Tripathy-Lang

    Some scientists think the “Great Unconformity” was caused by a single erosion event. Recent work suggests the phenomenon might not be so simple.

    At right is the first stratigraphic section of the Grand Canyon, from John Wesley Powell’s 1875 report, showing what would later be termed the “Great Unconformity”. Letter A is the metamorphic basement—the oldest rocks. B is the Precambrian Grand Canyon Supergroup, which is composed of tilted sedimentary rocks that lack fossil assemblages. C indicates Paleozoic rocks, which contain fossils marking the explosion of life. Two unconformities can be seen at x and y, with the former marking the “Great Unconformity”. At left is a recent photograph of Grand Canyon from Walhalla Plateau, with the red line showing the “Great Unconformity”. Credit: Annie Scott/USGS.

    On 24 May 1869, a group of explorers led by John Wesley Powell set out on a 3-month-long adventure, during which they explored the gorges and chasms of the Colorado River. Multiple expeditions over the next few years culminated in Powell’s vivid 1875 report [Making of America (below)]: “Dame Nature kneaded this batch of dough very thoroughly,” he wrote of Precambrian rocks in the Grand Canyon.

    Powell’s report also includes a detailed drawing of the “Great Unconformity”, so named by geologist Clarence Dutton in 1882.

    The “Great Unconformity” commonly marks the surface that separates rocks full of fossils, younger than about 500 million years, from largely fossil free rocks dating anywhere from hundreds of millions to even billions of years earlier, said Rebecca Flowers, a thermochronologist at the University of Colorado-Boulder. This surface betrays a history of either nondeposition or erosion (or both) lurking in the boundary between the rock strata.

    Unconformities are relatively common in the geologic record and can be thought of like pages missing from a book, explained Kalin McDannell, a postdoctoral geologist at Dartmouth College. “You can think of [the “Great Unconformity”] as missing chapters” from Earth’s geologic history, he said, with many of the same chapters missing from strata across the globe.

    Because the rocks are gone, investigating unconformities is challenging. “You have to use other techniques…to tease out that missing history,” said Flowers. In a talk at the Geological Society of America (GSA) Connects 2022 meeting in Denver, she discussed whether the “Great Unconformity” needed to be produced by a synchronous, global erosional event. She argued that it may instead be better characterized as many “Great Unconformities”, based on modeling when these chapters were torn from the book of Earth history.

    Missing Rocks, Missing Time

    To figure out how much time is missing between old Precambrian rocks and younger, fossil-rich strata on top, scientists turn to thermochronology: the temperature history of a rock—when it was hot and when it was not.

    Beneath Earth’s surface the deeper the rock is the hotter it is. (This somewhat predictable relationship is called the geothermal gradient.) Combining that information with when a rock was hot or not tells you when a rock was at a certain depth.

    That information combination, said Flowers, “can give you insight into when overlying rocks were removed by erosion and when [the sampled rocks] came to the surface.”

    However, a “cooling age” calculated from a single mineral taken from a particular rock does not yield a unique cooling history; it’s just one point on what could be a simple or complicated surfaceward journey. Determining the intricacies of a rock’s travels requires using multiple minerals from a single sample that record different parts of the path and consideration of geologic information, said McDannell, who was not involved in Flowers’s study but is actively applying thermochronologic methods to research the origin of the “Great Unconformity”.

    Snowball Earth or Something Else?

    If a global-scale phenomenon really did generate the “Great Unconformity”, Snowball Earth may be the culprit. In this famous scenario, ice sheets like those on Greenland and Antarctica today extended all the way to the equator. If a link between Snowball Earth and the Great Unconformity resulting from subglacial erosion—glaciers scouring the continents—exists, scientists should be able to see major erosion between about 720 million and 635 million years ago (the Cryogenian period), said McDannell.

    The best places to look for evidence of Snowball Earth [PNAS (below)] are in areas least affected by more recent events, said Flowers—a tall order considering that the Great Unconformity formed many hundreds of millions of years ago. Her approach involved strategically targeting locations that have other geologic constraints on when the unconformity was at the surface.

    In her GSA talk, Flowers discussed how thermochronologic results from the east and west sections of the Grand Canyon suggest different thermal histories—different routes to the surface—at a scale of tens of kilometers. Faulting that resulted from tectonic activity, she said, most likely drove the rocks’ upward rise at disparate times. Moreover, her models, which incorporate geologic constraints, hint at both parts of the canyon cooling prior to the time of Snowball Earth. Similarly, Flowers and her colleagues argued that in Colorado, the rocks were already at the surface by Snowball Earth time. In this example, she said, “the ‘Great Unconformity’ erosional surface [likely] formed before the Snowball Earth glaciations.”

    Models and Observations

    Scientists rely on different modeling programs that simulate thermal histories with the goal of reproducing the thermochronologic data, said Kendra Murray, an assistant professor at Idaho State University who was not involved in Flowers’s research.

    “Fitting the [thermochronologic] data is the minimum requirement, and that does not prove a model right—just consistent,” explained Kerry Gallagher, a professor at the University of Rennes in France who wrote QTQt, one of the two most commonly used modeling programs.

    These modeling programs can incorporate geologic observations as well and can explore whether the best-fitting models are driven by thermochronologic data or external geologic constraints. This kind of exploration “brings a lot more clarity to what parts of our information are most important to the story that we think we see,” Murray said.

    In the Grand Canyon and Colorado examples Flowers discussed, she and her colleagues combined thermochronologic data with independent geologic constraints in a program called HeFTy. In her talk, she referred to geologic constraints that all geologists agree on as “geologic facts.” For instance, rocks overlying an unconformity define the time at which those rocks must have been at the surface.

    However, McDannell said the conclusions of Flowers and colleagues on the Grand Canyon require the use of those geologic constraints. The thermochronologic data on their own aren’t driving these models, he said, which means that how those constraints are integrated into the modeling program becomes paramount.

    In Flowers’s talk, she discussed geologic features, called injectites, in the Colorado example that helped her and her colleagues argue for pre–Snowball Earth erosion. Flowers said the injectites suggest that the rocks were near the surface when these curious features were emplaced.

    But that interpretation and the associated temperature constraints are debatable, said McDannell.

    “If everyone was happy with those constraints, there wouldn’t be any arguments going on,” said Gallagher.

    Glaciers Versus Tectonics

    Testing the connection between Snowball Earth and the “Great Unconformity” is simpler in places that weren’t undergoing active tectonic faulting at around the same time, said Brenhin Keller, an assistant professor in geology at Dartmouth. In the Grand Canyon, that tectonic history could obscure a glacial signature.

    Instead, examining rocks far from semicontemporaneous tectonics, said McDannell, would mean a simpler history to unwind. For instance, he and Keller collected data from tectonically quiescent central Canada, and their modeling, with and without geologic constraints, suggested significant Cryogenian exhumation—and therefore a Snowball Earth–”Great Unconformity” connection.

    Rocks with similar palimpsests around the world need to be studied, Keller said. If a global pattern of Cryogenian erosion appears, that would strengthen the idea that Snowball Earth glaciations caused at least some of the surfaces of the “Great Unconformity”.

    Nevertheless, Flowers’s proposition of multiple “Great Unconformities” (with multiple causations) may be valid. Some causes could be tectonic, others could be glacial, and still others might be both.

    “There’s more than one period of erosion that goes into any given unconformity surface,” said Keller. To address the proposed Snowball Earth–”Great Unconformity” link, he said, the question is, “Was there erosion in the Cryogenian?” If so, then perhaps that’s the “Greatest Unconformity”.

    Science article:
    Making of America

    Science paper:
    PNAS 2018
    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. Use “Reply”.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 11:00 am on December 27, 2022 Permalink | Reply
    Tags: "Satellite Data Reveal Uptick in Cover Cropping on Farms", , , , , , , Eos, Over the course of a decade farmers growing corn and soybeans in the U.S. Midwest increased their adoption of cover cropping—a tenet of so-called conservation agriculture—by fourfold.   

    From “Eos” : “Satellite Data Reveal Uptick in Cover Cropping on Farms” 

    Eos news bloc

    From “Eos”



    Katherine Kornei

    Over the course of a decade farmers growing corn and soybeans in the U.S. Midwest increased their adoption of cover cropping—a tenet of so-called conservation agriculture—by fourfold.

    A South Dakota farmer planted a straight radish cover crop into winter wheat stubble to simulate “natural strip till” and increase biological activity to enhance residue breakdown, allowing the soil to warm up more quickly in the spring for planting corn. Credit: USDA NRCS SD Michael Stephens, Pierre.

    Agriculture is hard on the planet, at least in the stereotypical caricature of “big ag”: Crops are propelled to maturity with a plethora of fertilizers, herbicides, and pesticides—the runoff of which pollutes waterways and triggers harmful algal blooms—and the land is often left barren between planting cycles, leading to the erosion of nutrient-rich topsoil. But there’s reason to be hopeful, new results revealed; farms that grow corn and soybeans across the American Midwest are increasingly planting cover crops. That’s a heartening trend, the researchers suggested, because cover crops benefit the environment in a myriad of ways.

    These Crops Aren’t Harvested

    In the midwestern United States, thousands upon thousands of acres are devoted to growing corn and soybeans. Those cash crops—used to produce animal feed, cooking oil, fuel, and a host of other products—are typically planted in April or May and harvested around October. That timing opens up the possibility of planting a so-called cover crop in the late fall that is dormant during the winter and then emerges the following spring. Cover crops used in the Midwest include a wide variety of species such as cereal rye, barley, crimson clover, and field peas. But they aren’t meant to be harvested, said Kaiyu Guan, an Earth system scientist at the University of Illinois-Urbana-Champaign. Instead, they’re grown to help keep the soil healthy and reduce runoff and erosion, said Guan. “Cover cropping is a major conservation practice.”

    Guan is part of a team, led by Qu Zhou, also at the University of Illinois-Urbana-Champaign that recently studied the prevalence of cover cropping on land used to grow corn and soybeans. The team analyzed trends across the midwestern United States over 2 decades from 2000 to 2021. It’s important to get a handle on how cover crop adoption has waxed and waned over time, said Guan. That’s because the national government, along with state and regional organizations, has periodically offered financial incentives to farmers to adopt conservation practices such as cover cropping. It’s useful to understand whether those incentives have been effective, said Guan. “Essentially, we’d like to see what’s going on with all of those investments.”

    Looking for Green

    The researchers analyzed satellite imagery obtained at visible and near-infrared wavelengths from 2000 to 2021 spanning 12 states across the Midwest. For each 30- × 30-meter pixel in their data set, they calculated a parameter known as the Normalized Difference Vegetation Index (NDVI). NDVI is essentially a measure of photosynthetic capability—values close to 1 indicate the presence of lots of green leaves, and values close to 0 correspond to no vegetation. “It’s basically related to greenness,” said Eileen Kladivko, a soil scientist at Purdue University in West Lafayette, Ind., and a founding member of the Midwest Cover Crops Council who was not involved in the research.

    With a daily time series of those NDVI data in hand, the team’s next challenge was to determine exactly what part of the NDVI signal was due to cover crops. Bare soil, corn and soybean crops, and even weeds could be contaminating the data. The researchers first assumed that the lowest NDVI values they recorded—which tended to appear between October and April—corresponded to bare soil. Signals recorded from June through September—that is, the cash crop growing season—were largely due to the growth of corn and soybeans, the team surmised. By subtracting the contributions of soil and cash crops from the NDVI time series, the researchers isolated signals most likely due to cover crops. “We use the time series information to unmix these signals,” said team member Sheng Wang, an environmental scientist at the University of Illinois-Urbana-Champaign.

    To deal with the issue of weeds, the team applied a set of spatially and temporally dependent thresholds that considered parameters such as air temperature, precipitation, and soil type. “We developed a dynamic method to essentially take into account the environmental conditions associated with cover crop growth,” said Guan. By masking out pixels that didn’t satisfy those thresholds, the team homed in on a set of signals most likely to be free of contamination from weeds. To address the problem of winter-grown cash crops, the researchers used crop data from sources such as the U.S. Department of Agriculture National Agricultural Statistics Service to isolate pixels most likely to represent corn and soybeans.
    First Steady, Then Growth

    Zhou and his collaborators calculated the rate at which corn and soybean farmland was planted with cover crops each year from 2000 to 2021. Cover crop usage remained nearly constant the first 10 years of the study period, the team noted, at roughly 1.1%, or about 6,000 square kilometers (1.5 million acres). But the practice took off in 2010, the researchers found. Each year thereafter, about 0.4% more farmland was planted with cover crops. By 2021, the cover crop adoption rate in the Midwest had increased to 7.2%, or more than 40,000 square kilometers (10 million acres), the team reported in November in Geophysical Research Letters [below].

    But the gains were far from uniform, the researchers noted. For example, Indiana has been particularly successful at implementing cover crops, but Illinois less so, said Guan. “You can clearly see there’s a spatial disparity between states.”

    When the researchers analyzed trends in government funding for cover cropping, they found that spending was stagnant from 2000 to 2010 but has steadily increased since then. That syncs up with the pattern seen in the satellite data, said Guan. “It’s coaligned with significant increases in government investments in conservation practices.”

    It makes sense that cover cropping and financial support for the practice would be correlated, the researchers proposed. Planting a cover crop requires additional labor and resources such as seeds, which are associated with investments of time and money. “Ultimately, adopting a cover crop is, for most farmers, an economic decision,” said Guan. “The most critical question for farmers is whether the bottom line works.”

    More Than Dollars

    But the availability of funding isn’t the be-all and end-all when it comes to cover crop adoption, said Kladivko. In places such as Indiana, for instance, surveys generally revealed that far more acres are planted with cover crops than would be expected based on disbursements from environmental programs, she said. “A substantial number of farmers adopt cover crops without ever having received government funding.”

    What can make a big difference in cover crop adoption is the presence of committed staff members in local organizations who believe in, and promote, this form of conservation, said Kladivko. Word of mouth among farmers probably also plays a large role, she said. “Funding is part of it, but I don’t attribute all the increase that’s happened in the Midwest in the last 10 years to funding.”

    Science paper:
    Geophysical Research Letters
    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. Use “Reply”.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 10:36 am on December 27, 2022 Permalink | Reply
    Tags: "Winter Arctic Heatwave Drives Summer Impacts in Siberia", A cascade of land-atmosphere interactions resulting from a winter heatwave in Siberia led to significant summer impacts that further exacerbated the heatwave effects on the region., , , , , , , Eos   

    From “Eos” : “Winter Arctic Heatwave Drives Summer Impacts in Siberia” 

    Eos news bloc

    From “Eos”



    Donald Wuebbles

    A cascade of land-atmosphere interactions resulting from a winter heatwave in Siberia led to significant summer impacts that further exacerbated the heatwave effects on the region.

    Monthly average a) Snowmelt and b) snow cover for years 1981-2020 using data within the study region (50◦N-75◦Nand50◦E-120◦E). Gray lines indicate the years 1981-2019, with the dashed line indicating the 1981-2010 climatology. Red line indicates 2020. Soil moisture anomalies from 1981-2010 mean are shown for c-f) March through June. Dashed line delineates the study region. Small black boxes show the location of three regions, whose time series are shown in g-i). Elevated soil moisture is observed in March and April transitioning to dryness in May and June. Credit: Gloege et al., 2020, Figure 3.

    A heatwave in Siberia starting in January 2020 led to a cascade of events resulting in temperatures reaching 38◦C (100◦F) in June. The winter heatwave caused an early snow melt which elevated the soil moisture. This in turn caused earlier spring greening. As the heatwave persisted, soil moisture evaporated causing soil to be drier and trees to brown earlier in summer. Since the soil was drier than normal, the heat emanating from it was elevated which further exacerbated the heatwave. Gloege [2022] report that this line of evidence suggests that large-scale dynamics and land-atmosphere interactions both contributed to the magnitude and persistence of this record-breaking heatwave, in addition to the background changing climate effects on mean temperature. With Arctic temperatures increasing twice as fast as the global average, the role of land-atmosphere interactions will likely become more prominent in the future as the climate warms.

    Science paper:
    AGU Advances
    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. Use “Reply”.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 8:59 am on December 23, 2022 Permalink | Reply
    Tags: "Groundwater Replenishes Much Faster Than Scientists Previously Thought", , , , Eos,   

    From “Eos” : “Groundwater Replenishes Much Faster Than Scientists Previously Thought” 

    Eos news bloc

    From “Eos”



    Rachel Fritts

    A new climate-based model indicates that scientists may be underestimating groundwater’s importance in sustaining streams and plant life.

    Groundwater makes up most of the world’s liquid fresh water and might play a bigger role in sustaining streams and plant life than previously thought. Credit: Dr. Andrew Fisher/Wikimedia Commons, CC BY-SA 4.0. The following modifications were made: All type was replaced for readability.

    A large part of the world’s liquid freshwater supply comes from groundwater. These underground reservoirs of water—which are stored in soil and aquifers—feed streams, sustain agricultural lands, and provide drinking water to hundreds of millions of people.

    For that reason, researchers are keen to understand how quickly surface water replenishes, or “recharges,” groundwater stores. But measuring a vast, fluid, underground resource is easier said than done. In a new study, Berghuijs et al. found that recharge rates might double previous estimates.

    The research team produced an updated model of groundwater recharge using a recent global synthesis of regional groundwater measurements. They found that a single factor, climate aridity, accurately estimated how much precipitation trickled into groundwater across the globe: Arid locations had lower recharge rates than humid ones. The aridity-based model results closely mirrored field measurements and indicated that previous models vastly underestimated recharge rates.

    This finding has implications for the water cycle, the authors say. For instance, groundwater likely contributes more to river flow and plant water use than previous models predicted. That could scale up to affect the entire ecosystem.

    Although groundwater might recharge more quickly than expected, the team cautions that groundwater is still overused in many places, especially in arid regions. Groundwater depletion threatens water security in these areas, they say, and the impacts of climate change remain unknown. (Geophysical Research Letters).

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 2:05 pm on December 13, 2022 Permalink | Reply
    Tags: "Ocean Data Platform"-A searchable data catalog which would make information easier to find., "Spurring Ocean Research with Open Data", , Compiling Uniform Ocean Data, , Eos, HUB Ocean-a nonprofit in Norway that now hopes to ease the barriers to communicated knowledge, Less than a quarter of the world’s oceans have been mapped., Ocean data abound but accessing the data is a challenge making tackling climate change difficult. One nonprofit is trying to compile them., , Remote and near sensors and satellites and tidal buoys and deep-sea robots and crewed research vessels are collecting more ocean data than ever. Costs have fallen and technology has improved., The current patchwork of data analysis tools can be a barrier for those looking to work with unfamiliar data., The tool dubbed the "Ocean Data Connector"   

    From “Eos” : “Spurring Ocean Research with Open Data” 

    Eos news bloc

    From “Eos”



    Robin Donovan

    Ocean data abound but accessing the data is a challenge making tackling climate change difficult. One nonprofit is trying to compile them.

    A data visualization shows shipping lanes and estimated carbon dioxide emissions based on HUB Ocean’s Ship Emissions Tracker data set, which is unique to the Ocean Data Platform. Credit: Mogens L. Mathiesen, HUB Ocean.

    Remote and near sensors, satellites, tidal buoys, deep-sea robots, and crewed research vessels are collecting more ocean data than ever before as the costs of some of these devices have fallen and technology has improved. Despite this effort, less than a quarter of the world’s oceans have been mapped, and scientists and societies are still tackling questions about ocean ecosystems and how to adapt to global challenges such as climate change.

    Many regional and global databases hold ocean data, some of which are available to the public. Unfortunately, because data types are many and formatting standards do not always exist, even when data are openly available, not every researcher has the time, skill, or know-how to access them.

    “These databases are a valuable source of information but it is very time-consuming to find any data,” said Anna Silyakova, an oceanographer at HUB Ocean-a nonprofit in Norway that now hopes to ease those barriers.

    Compiling Uniform Ocean Data

    HUB Ocean leaders plan to work with data curators to help them structure their databases in the cloud. Meanwhile, the nonprofit’s scientists are compiling open data from around the world, partnering with businesses and scientists to create a freely available and, hopefully, easier-to-use repository, the Ocean Data Platform.

    “There are so many actors, people, individuals, initiatives, and institutions that gather data,” Silyakova said. “But as long as you keep [them] all in different places, you will never have a full picture of what is happening in the ocean, how our activities might affect the ocean, and how ocean-climate related processes can affect humanity.” A searchable data catalog would make information easier to find.

    The tool will address twin issues that have kept data from being shared or searchable. First, the nonprofit’s staff, who have developed the expertise to work with a wide range of data types, are recruiting researchers and corporate entities to share their data directly. Second, HUB Ocean plans to make it easier than ever for people who download, repurpose, or reshare data to credit the original source.

    Silyakova says that to date, there are regional services that focus on compiling data from specific countries or regions, such as the United States or Europe, but no similar service at the scale of the Ocean Data Platform.

    The Ocean Data Platform isn’t publicly available yet, as the nonprofit is working with a few of its partners to test it. A launch is tentatively planned for 2023, and HUB Ocean presenters will recruit new testers at a 12 December session at AGU’s Fall Meeting 2022.

    Crunching Numbers Made Easy

    An online workspace is also in the works, tailored to researchers without experience working with various file types. The current patchwork of data analysis tools can be a barrier for those looking to work with unfamiliar data. “If you have to go and download multiple different files that come in lots of different formats, those types of things can [make it] hard for someone to get started using the data,” said Tara Zeynep Baris, a senior data scientist for HUB Ocean.

    The tool dubbed the “Ocean Data Connector“, is an analytical computing environment that scientists can use alongside the platform itself to search for, compile, and analyze data. This means scientists can work with data without needing excessive computing power and storage space.

    Along with gathering available data, Silyakova said HUB Ocean is working at the interface between science, industry, and government, encouraging agencies to make their data publicly available. Some scientists are concerned that sharing data prior to their publication in a scholarly journal could encourage editors to shy away from their studies.

    “Obviously, there’s no way for us to make sure everyone cites [the data], but it’s the same as if they were getting the data from anywhere else,” Baris said. She hopes including clear citation information with each data set will alleviate potential concerns about submissions to the Ocean Data Platform being circulated without attribution.

    “I think it’s a need for this global community of research observatories to try to get better and better at making the data findable and usable,” said Woods Hole Oceanographic Institution marine meteorologist Jim Edson. He leads the Ocean Observatories Initiative, which shares data through its Data Explorer tool. Edson has also collaborated with NOAA’s National Data Buoy Center. “We’ve worked with [NOAA] to get a subset of our data on their site,” he said. “It wasn’t easy.”

    The inclusion of commercial partners is unique to Hub Ocean compared to existing data repositories, he said. He agreed with the need for more and better data sharing. But it won’t be until after the Ocean Data Platform’s launch that scientists such as Edson will have a chance to truly test its worth.

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

  • richardmitnick 1:21 pm on December 13, 2022 Permalink | Reply
    Tags: "Making Underwater Cables SMART with Sensors", About every 70 kilometers along the entire length of each cable a long cylinder called a repeater amplifies the throughgoing signal., , Both the seismic and pressure sensors on SMART cables could more quickly inform authorities of incoming tsunamis., Data and communications, Earthquake early warning and tsunami tracking and climate change, Eos, Future cables that stretch across the ocean could also contain temperature and pressure and seismic sensors that would allow scientists to spy on the seafloor., Spanning thousands of underwater kilometers telecommunications cables-which look like garden hoses- contain at their center hair-thin optical fibers protected by sheaths of metals and other materials., The closer you can get a seismometer to the earthquake source the sooner you can transmit the fact that there has been an earthquake., The National Science Foundation is considering a cable that would connect New Zealand to McMurdo Station in Antarctica where researchers lack high-speed Internet connections., The optical fibers transmit data at the speed of light while copper in the cable carries the necessary electrical power., The Southern Ocean that surrounds Antarctica is the worst-instrumented part of the world., These cables begin and end at shore stations that provide power., Transoceanic Internet   

    From “Eos” : “Making Underwater Cables SMART with Sensors” 

    Eos news bloc

    From “Eos”



    Alka Tripathy-Lang
    Science Writer

    Future cables that stretch across the ocean, transmitting cat videos and financial transactions, could also contain temperature, pressure, and seismic sensors that would allow scientists to spy on the seafloor.

    In this map, colored lines depict the locations of transoceanic subsea cables. They cross oceans and wind their way around continents, stopping at various hubs, shown as open circles, along the way. Credit: TeleGeography’s Submarine Cable Map, CC BY-SA 4.0.

    About 8 years ago, at the end of a long day of meetings at the University of Hawai‘i at Mānoa, visiting speaker and seismologist Charlotte Rowe walked into Bruce Howe’s office. “He rolled a map out…that showed all the transoceanic telecommunications cables,” she recalled. He described a future in which these underwater cables could include seismic sensors every 50 to 100 kilometers, all around the world.

    Howe, a professor in the Department of Ocean and Resources Engineering, asked, “Would this be of interest to you seismologists?”

    Rowe responded, “Well, yes!”

    During that meeting, Howe asked Rowe to quantify just how useful underwater cables equipped with regularly spaced seismic sensors might be for seismologists. “With a few exceptions, all of our seismic networks are on land,” said Rowe. For Earth beneath the oceans, this means that “we don’t do a very good job of characterizing how seismic waves propagate through it.” After doing some calculations with a summer intern back at THe DOE’s Los Alamos National Laboratory, Rowe said, “the [modeled] improvement was stunning.”

    Since then, Rowe has been involved with the United Nations’ Joint Task Force on Science Monitoring and Reliable Telecommunications (SMART) Subsea Cables, for which Howe is chairperson. They’re working to outfit the ocean with temperature, pressure, and seismic sensors that would help with a host of problems, including earthquake early warning, tsunami tracking, and climate change.

    Rowe will update the scientific community on plans for SMART cables in various locations around the world at AGU’s Fall Meeting 2022 on Tuesday, 13 December.

    Transoceanic Internet

    The Internet might seem like a combination of satellites, the “cloud,” and data flitting through the air. In fact, the cloud consists of buildings full of servers scattered throughout the world, where physical cables connect to one other. Sending data across an ocean simply requires longer, tougher, specially engineered cables.

    Spanning thousands of underwater kilometers, telecommunications cables, which look like garden hoses, contain at their center hair-thin optical fibers protected by sheaths of metals and other materials, explained Howe. The optical fibers transmit data at the speed of light, while copper in the cable carries the necessary electrical power. This is how we see cat videos from other continents in real time; how we videoconference overseas coworkers, friends, or family; and how global financial transactions take place. “Without these cables, we would not have the Internet as we know it,” he said.

    These cables begin and end at shore stations that provide power. About every 70 kilometers along the entire length of each cable, a long cylinder called a repeater amplifies the throughgoing signal, said Howe. These cylinders, between 1 and 1.5 meters long, have enough space for sensors to sit within the mechanically protected, seawater-flooded end sections. The current plan is to find funds to add SMART sensor packages that measure temperature, pressure, and seismicity to future cable deployments to replace aging transoceanic telecommunication infrastructure.

    Portugal’s Once and Future Great Earthquake

    One of the first cables likely to include SMART sensors will maintain Portugal’s connection to the Azores and Madeira islands. Existing cables are nearing the end of their lifetimes, said Vitor Silva, an earthquake engineer and risk coordinator at the Global Earthquake Model Foundation. “We’ve been lobbying the government to make sure that the next time they replace the cables, [they’ll] be SMART.”

    Silva explained why Portugal is a good test case for the SMART sensors. In 1755, he said, the Great Lisbon Earthquake destroyed the nation’s capital. The earthquake, which may have been greater than magnitude 8.0, began southwest of Portugal’s coast, under the waters of the Atlantic Ocean. Following the rupture and collapse of countless structures, a tsunami inundated the coast as fires raged. Today, Portugal does not have an earthquake early-warning system akin to those in other earthquake-prone regions. In addition, many of Portugal’s buildings are not seismically sound, making them, and their inhabitants, vulnerable to shaking.

    By strategically laying the SMART cable where scientists suspect the seafloor will break, any such earthquake would be much more rapidly detected, according to a recent paper led by Silva [Bulletin of Earthquake Engineering (below)].

    “The closer you can get a seismometer to the earthquake source the sooner you can transmit the fact that there has been an earthquake,” explained Rowe.

    Silva and colleagues have also calculated how much money SMART cables could save Portugal should another offshore earthquake strike. The new cables are likely to cost 140 million euros. Making them SMART should add about 10%, upping the expense to 154 million euros. However, the cost could be recouped by saving peoples’ lives. By simulating various earthquake scenarios and determining how many people might die and using estimates for the cost of losing a person’s life, Silva and colleagues calculate that 170 million euros would be saved. “Including this technology could actually pay for the entire thing,” said Silva.

    Though Silva’s calculations didn’t account for tsunami warnings, both the seismic and pressure sensors on SMART cables could more quickly inform authorities of incoming ocean waves.

    “Detecting the first arrival of the earthquake waves [earlier] will help us get a more rapid and perhaps more accurate location and depth of the earthquake,” said Stuart Weinstein, deputy director of the Pacific Tsunami Warning Center and member of the joint task force. An earthquake’s location, depth, and magnitude factor into whether a tsunami is a possibility and guide initial tsunami alerts.

    Should a tsunami form, it changes sea level as it propagates, Weinstein explained. As the crest of a tsunami wave passes, sea level rises, and pressure increases on the sensor. Likewise, when the trough passes, sea level drops, and pressure decreases. In this way, pressure sensors can track tsunamis (not wind-driven surface waves) and validate forecasts produced from seismic data.

    Future Cables, Future Climate

    Additional sensors have been considered, said Howe, but “the key problem is many of those are not ready for 25-year life on the seafloor.” Plus, he said, adding too many sensors will turn industry off because most cables are privately owned. “To get implemented on a global scale, we have to keep this concept simple.”

    Currently, the joint task force is exploring external couplings, particularly for certain custom cables, said Rowe. These couplings would allow later installations of additional seismic instruments that might be able to measure a greater variety of signals than the small seismic sensors planned for the SMART cables. These external instruments, perhaps installed via underwater robot, could be more solidly coupled to the seafloor, which would enhance the signal’s integrity. This setup would solve two limitations of today’s scant ocean bottom seismometer deployments—power and communication—which would both be supplied by the cable, Rowe explained.

    In addition, the National Science Foundation is considering a cable that would connect New Zealand to McMurdo Station in Antarctica where researchers lack high-speed Internet connections. The Southern Ocean that surrounds Antarctica is the worst-instrumented part of the world, said Rowe. “There’s so much that we could learn” from a SMART-equipped cable, she said.

    Another intriguing avenue for the future, according to Rowe, involves hydroacoustic sensors (hydrophones) that listen to sounds propagating through the water. “The ocean is a very, very noisy environment,” she said. Earthquakes rumble. Underwater volcanoes explode. Marine mammals splash and sing. Icebergs crack and groan. Ships clack and clang. Listening to the sea’s sounds is one way to track changes and patterns in the ocean, though hydrophones aren’t part of current plan for the sensor package.

    SMART cables could also keep tabs on climate change. Pressure sensors would measure components of ocean circulation, whereas temperature sensors could inform scientists about how ocean bottom temperatures are changing, Howe explained.

    Howe noted that scientists cannot trace a direct line from a person suffering from the effects of drought to a specific measurement. Nevertheless, he said, “the climate measurements [along with other observations] will affect everyone on the planet, albeit indirectly and over longer timescales.”

    Science paper:
    Bulletin of Earthquake Engineering

    See the full article here .

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


    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Eos” is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

Compose new post
Next post/Next comment
Previous post/Previous comment
Show/Hide comments
Go to top
Go to login
Show/Hide help
shift + esc
%d bloggers like this: