Gerrit L. Verschuur | |
---|---|
Born | 1937 Cape Town |
Nationality | American Naturalized 1975 |
Alma mater | Rhodes University University of Manchester |
Scientific career | |
Fields | Radio astronomy |
Institutions | University of Memphis |
Gerrit L. Verschuur (born in 1937 in Cape Town, South Africa) is an American scientist who is best known for his work in radio astronomy. Though a pioneer in that field, Verschuur is also an author (he has written about astronomy, natural disasters, and earth sciences), inventor, adjunct professor of physics for the University of Memphis, and Astronomer Emeritus - Arecibo Observatory and now semi-retired. He served for a time as the Chief Scientist for Translucent Technologies, LLC; a company which is based in Memphis, Tennessee. [1]
In 1992 Verschuur became a resident of the City of Lakeland, which is located in Shelby County, Tennessee, northwest of Memphis. In 2001 Verschuur was elected, and served a four-year term as commissioner. In 2007 he was elected again and served for a total of 10 years. In Lakeland, Verschuur was also the President of the Garner Lake Association [ permanent dead link ]. Since 1986 he has been married to Dr. Joan Schmelz, a fellow scientist whose specialty is solar astronomy, specifically coronal loops. [2] Verschuur has one son who lives in England. [1]
During his years living beside the lake in Lakeland he made a fundamental discovery concerning the manner in which light interacts with a so-called Secchi Disk that is used to measure the transparency of lake and ocean waters. The disk had been invented in the mid-nineteenth century by a Jesuit priest (Angela Secchi) but no one before Verschuur had understand the optics underlying the measurement technique [3] .
Verschuur has taught at the University of Manchester, Rhodes University, the universities of Colorado and Maryland, UCLA, and the University of California, Berkeley, among others. [4] He has been an annual speaker at Mid-South Stargaze, "the annual amateur astronomers conference and star party held at Rainwater Observatory in French Camp, Mississippi." [5] In 1971 Verschuur was hired as the first Director of Fiske Planetarium for the University of Colorado at Boulder, [6] and in 1980 he worked with Dr. John C. Lilly. [4]
In his primary field of study Verschuur "pioneered the measurement of the interstellar magnetic field using the 21-cm Zeeman effect technique." [7] A thing which, according to Virginia Trimble, for the first time allowed astronomers to "measure magnetic strengths and their place-to-place variations with some confidence." [8]
Gerrit L. Verschuur was born in 1937 in Cape Town, South Africa, at the foot of Table Mountain. In 1936, his parents had emigrated from the Netherlands and settled in Cape Town. Two years after he was born—in 1939—his parents moved again, choosing a suburb of Cape Town named Lakeside. While he was living there, Verschuur attended Muizenberg Junior School. Then, when his parents moved to Port Elizabeth in 1950, he attended Grey Junior and subsequently Grey High School.[ citation needed ]
After graduation he began a six-year stint at Rhodes University in Grahamstown where he earned a BSc in 1957—Majors: Math, Physics, & Applied math; a BSc (Hons) of Physics in 1958; and a MSc degree of physics, in 1960.
In December 1960 he sailed for Southampton, England on Edinburgh Castle, a ship owned by the Union Castle Line. [9] It was one of the last passenger mail boats to ply the SA-England route, but was sold for scrap in 1967. [10]
Verschuur is at the center of a recent debate over the age of the universe. [11] [12] He claimed that images from the Wilkinson Microwave Anisotropy Probe are not pictures of the universe in its early form, but rather hydrogen gas clouds in our own galaxy. If he is shown to be correct, much work relating to the Big Bang theory would be undermined.
On December 10, 2007, his work with respect to COBE, WMAP, and HI, was published in The Astrophysical Journal. [13] However, Land and Slosar [14] claimed that the data did not support the correlation claimed by Verschuur. He subsequently published 4 more papers on the subject backing up his claims [15] [16] [17] [18] .
His current research is conducted in partnership with Joan Schmelz, his wife, and elaborates on the exciting discovery they made that the so-called high-velocity clouds are produced by supernova events that occurred relatively close to the Sun, of order hundreds of light years distant, several hundred thousand years ago. They solved the 60 year-old mystery concerning the distance to certain clouds when they found that neutron stars (left over after the explosion) exists in spectroscopic binary systems, the primary example having been discovered by researchers in Belgium led by Ana Escorza who used GAIA data to identify likely neutron star candidates. [19] [20] [21] [22] [23]
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang. The simplest model in general agreement with observed phenomena is the Lambda-CDM model—that is, that clustering and merging allows galaxies to accumulate mass, determining both their shape and structure. Hydrodynamics simulation, which simulates both baryons and dark matter, is widely used to study galaxy formation and evolution.
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, H2), and the formation of H II regions. This is in contrast to other areas of the interstellar medium that contain predominantly ionized gas.
In 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926.
A rogue planet is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf. Rogue planets may originate from planetary systems in which they are formed and later ejected, or they can also form on their own, outside a planetary system. The Milky Way alone may have billions to trillions of rogue planets, a range the upcoming Nancy Grace Roman Space Telescope will likely be able to narrow down.
Sagittarius A*, abbreviated Sgr A*, is the supermassive black hole at the Galactic Center of the Milky Way. It is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster (M6) and Lambda Scorpii.
The Perseus molecular cloud is a nearby giant molecular cloud in the constellation of Perseus and contains over 10,000 solar masses of gas and dust covering an area of 6 by 2 degrees. Unlike the Orion molecular cloud it is almost invisible apart from two clusters, IC 348 and NGC 1333, where low-mass stars are formed. It is very bright at mid and far-infrared wavelengths and in the submillimeter originating in dust heated by the newly formed low-mass stars.
NGC 5986 is a globular cluster of stars in the southern constellation of Lupus, located at a distance of approximately 34 kilolight-years from the Sun. It was discovered by Scottish astronomer James Dunlop on May 10, 1826. John L. E. Dreyer described it as, "a remarkable object, a globular cluster, very bright, large, round, very gradually brighter middle, stars of 13th to 15th magnitude". Its prograde–retrograde orbit through the Milky Way galaxy is considered irregular and highly eccentric. It has a mean heliocentric radial velocity of +100 km/s. The galacto-centric distance is 17 kly (5.2 kpc), which puts it in the galaxy's inner halo.
In astronomy, Calvera is an X-ray source in the constellation Ursa Minor, identified in 2007 as an isolated neutron star. It is one of the hottest and closest of its kind to Earth.
Epsilon Chamaeleontis, Latinized from ε Chamaeleontis, is a triple star located in the southern circumpolar constellation Chamaeleon. The primary and secondary have apparent magnitudes of 5.33 and 6.02, making them visible to the naked eye. Hipparcos parallax measurements place the system at a distance of 360 light years and is currently receding with a heliocentric radial velocity of 13 km/s.
HD 162826 is a star in the constellation Hercules. It is about 110 light-years away from Earth. With an apparent magnitude of 6.55, the star can be found with binoculars or a low-power telescope by reference to nearby Vega in the constellation Lyra.
HD 61005, also known as HIP 36948 and The Moth, is a young star located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 8.22, making it readily visible in binoculars, but not to the naked eye. The object is located relatively close at a distance of 119 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 22.6 km/s.
Pierre Cox is a French astronomer. Born in Paris to a Dutch composer father and a Belgian pianist mother, he led a musically-oriented childhood from which he rebelled at age 17 to study physics at the Université de Paris-Sud. He is known for his research in the area of millimeter and infrared observations of star-forming regions, evolved stars, and high-redshift galaxies. He has published over 250 refereed papers with more than 22,000 citations in total. Cox is currently a Director of Research (DR1) at CNRS, working at the Institut d'Astrophysique de Paris. From 2013 - 2018, Cox was the Director of ALMA, a position requiring coordinating the efforts of many countries that Cox likened to "being the Secretary General of United Nations". He was previously the Director of the Institut de radioastronomie millimétrique from 2006 through 2013. Prior to IRAM, he had been an astronomer at the Max Planck Institute for Radio Astronomy, the Marseille Observatory, and then the Institut d’Astrophysique Spatiale, an observatory of the CNRS at the Université de Paris-Sud in Orsay. Pierre's hobbies including drawing and playing piano. He speaks five languages fluently.
The KBC Void is an immense, comparatively empty region of space, named after astronomers Ryan Keenan, Amy Barger, and Lennox Cowie, who studied it in 2013. The existence of a local underdensity has been the subject of many pieces of literature and research articles.
NGC 4660 is an elliptical galaxy located about 63 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on March 15, 1784 and is a member of the Virgo Cluster.
The small planet radius gap is an observed scarcity of planets with radii between 1.5 and 2 times Earth's radius, likely due to photoevaporation-driven mass loss. A bimodality in the Kepler exoplanet population was first observed in 2013, and was noted as possibly confirming an emerging hypothesis that photoevaporation could drive atmospheric mass loss on close-in, low-mass planets. This would lead to a population of bare, rocky cores with smaller radii at small separations from their parent stars, and planets with thick hydrogen- and helium-dominated envelopes with larger radii at larger separations. The bimodality in the distribution was confirmed with higher-precision data in the California-Kepler Survey in 2017, which was shown to match the predictions of the photoevaporative mass-loss hypothesis later that year.
Gloria Dubner is an Argentinian astrophysicist and Director of the Instituto de Astronomía y Física del Espacio in Buenos Aires and a Senior Researcher at the National Scientific and Technical Research Council. She is known for her research on supernovas.
Sangeeta Malhotra is an astrophysicist who studies galaxies, their contents, and their effects on the universe around them. The objects she studies range from our own Milky Way galaxy to some of the earliest and most distant known galaxies in the epoch of cosmic dawn.
Misty C. Bentz is an American astrophysicist and Professor of Physics and Astronomy at Georgia State University. She is best known for her work on supermassive black hole mass measurements and black hole scaling relationships.
{{cite web}}
: CS1 maint: bot: original URL status unknown (link)