Misplaced Pages

#673326

58-787: The Center for Astrophysics | Harvard & Smithsonian ( CfA ), previously known as the Harvard–Smithsonian Center for Astrophysics , is an astrophysics research institute jointly operated by the Harvard College Observatory and Smithsonian Astrophysical Observatory . Founded in 1973 and headquartered in Cambridge, Massachusetts , United States, 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

116-625: A group of ten associate editors from Europe and the United States, established The Astrophysical Journal: An International Review of Spectroscopy and Astronomical Physics . It was intended that the journal would fill the gap between journals in astronomy and physics, providing a venue for publication of articles on astronomical applications of the spectroscope; on laboratory research closely allied to astronomical physics, including wavelength determinations of metallic and gaseous spectra and experiments on radiation and absorption; on theories of

174-508: A guide to understanding of other stars. The topic of how stars change, or stellar evolution, is often modeled by placing the varieties of star types in their respective positions on the Hertzsprung–Russell diagram , which can be viewed as representing the state of a stellar object, from birth to destruction. Theoretical astrophysicists use a wide variety of tools which include analytical models (for example, polytropes to approximate

232-575: 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 ,

290-484: 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

348-463: A millisecond timescale ( millisecond pulsars ) or combine years of data ( pulsar deceleration studies). The information obtained from these different timescales is very different. The study of the Sun has a special place in observational astrophysics. Due to the tremendous distance of all other stars, the Sun can be observed in a kind of detail unparalleled by any other star. Understanding the Sun serves as

406-561: A model or help in choosing between several alternate or conflicting models. Theorists also try to generate or modify models to take into account new data. In the case of an inconsistency, the general tendency is to try to make minimal modifications to the model to fit the data. In some cases, a large amount of inconsistent data over time may lead to total abandonment of a model. Topics studied by theoretical astrophysicists include stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in

464-606: 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

522-569: A number of major works related to massive compact halo objects , was named the third director of the CfA in 2004. Today Alcock oversees one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $ 100 million. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 PhD students , more than 100 postdoctoral researchers , and roughly 25 undergraduate astronomy and astrophysics majors from Harvard College . SAO, meanwhile, hosts

580-660: 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 NASA 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

638-542: A substantial amount of work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include their attempts to determine the properties of dark matter , dark energy , black holes , and other celestial bodies ; and the origin and ultimate fate of the universe . Topics also studied by theoretical astrophysicists include Solar System formation and evolution ; stellar dynamics and evolution ; galaxy formation and evolution ; magnetohydrodynamics ; large-scale structure of matter in

SECTION 10

#1732773231674

696-635: Is mainly concerned with finding out the measurable implications of physical models . It is the practice of observing celestial objects by using telescopes and other astronomical apparatus. Most astrophysical observations are made using the electromagnetic spectrum . Other than electromagnetic radiation, few things may be observed from the Earth that originate from great distances. A few gravitational wave observatories have been constructed, but gravitational waves are extremely difficult to detect. Neutrino observatories have also been built, primarily to study

754-506: 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

812-497: 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. The result is widely regarded as a triumph not only of observational astronomy , but of its intersection with theoretical astrophysics . Union of the observational and theoretical subfields of astrophysics has been

870-479: 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

928-516: The Lambda-CDM model , are the Big Bang , cosmic inflation , dark matter, dark energy and fundamental theories of physics. The roots of astrophysics can be found in the seventeenth century emergence of a unified physics, in which the same laws applied to the celestial and terrestrial realms. There were scientists who were qualified in both physics and astronomy who laid the firm foundation for

986-719: 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. Research across the CfA is organized into six divisions and seven research centers: The CfA is also host to the Harvard University Department of Astronomy, large central engineering and computation facilities,

1044-712: 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 Astronomy and Astrophysics Decadal Survey ("Astro2020"). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra. SAO

1102-659: 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. 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 ,

1160-584: 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,

1218-611: The application of computers to astrophysical problems. 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

SECTION 20

#1732773231674

1276-649: The interstellar medium and the cosmic microwave background . Emissions from these objects are examined across all parts of the electromagnetic spectrum , and the properties examined include luminosity , density , temperature , and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics , electromagnetism , statistical mechanics , thermodynamics , quantum mechanics , relativity , nuclear and particle physics , and atomic and molecular physics . In practice, modern astronomical research often involves

1334-508: 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 2022) is Lisa Kewley , who succeeds Charles R. Alcock (Director from 2004 to 2022), Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982). The Center for Astrophysics | Harvard & Smithsonian

1392-408: The 17th century, natural philosophers such as Galileo , Descartes , and Newton began to maintain that the celestial and terrestrial regions were made of similar kinds of material and were subject to the same natural laws . Their challenge was that the tools had not yet been invented with which to prove these assertions. For much of the nineteenth century, astronomical research was focused on

1450-680: 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

1508-689: 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 and 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

1566-586: The Science Education Department, the John G. Wolbach Library, the world's largest database of astronomy and physics papers (ADS) , and the world's largest collection of astronomical photographic plates. 42°22′53″N 71°07′42″W  /  42.38146°N 71.12837°W  / 42.38146; -71.12837 Astrophysics Among the subjects studied are the Sun ( solar physics ), other stars , galaxies , extrasolar planets ,

1624-477: The Sun, Moon, planets, comets, meteors, and nebulae; and on instrumentation for telescopes and laboratories. Around 1920, following the discovery of the Hertzsprung–Russell diagram still used as the basis for classifying stars and their evolution, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars , in his paper The Internal Constitution of the Stars . At that time,

1682-430: The Sun. Cosmic rays consisting of very high-energy particles can be observed hitting the Earth's atmosphere. Observations can also vary in their time scale. Most optical observations take minutes to hours, so phenomena that change faster than this cannot readily be observed. However, historical data on some objects is available, spanning centuries or millennia . On the other hand, radio observations may look at events on

1740-494: The behaviors of a star) and computational numerical simulations . Each has some advantages. Analytical models of a process are generally better for giving insight into the heart of what is going on. Numerical models can reveal the existence of phenomena and effects that would otherwise not be seen. Theorists in astrophysics endeavor to create theoretical models and figure out the observational consequences of those models. This helps allow observers to look for data that can refute

1798-510: The current science of astrophysics. In modern times, students continue to be drawn to astrophysics due to its popularization by the Royal Astronomical Society and notable educators such as prominent professors Lawrence Krauss , Subrahmanyan Chandrasekhar , Stephen Hawking , Hubert Reeves , Carl Sagan and Patrick Moore . The efforts of the early, late, and present scientists continue to attract young people to study

Harvard–Smithsonian Center for Astrophysics - Misplaced Pages Continue

1856-422: 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 (GMT) and the Chandra X-ray Observatory , one of NASA 's Great Observatories . Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in

1914-450: 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 PhD 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

1972-443: The end of the 20th century, studies of astronomical spectra had expanded to cover wavelengths extending from radio waves through optical, x-ray, and gamma wavelengths. In the 21st century, it further expanded to include observations based on gravitational waves . Observational astronomy is a division of the astronomical science that is concerned with recording and interpreting data, in contrast with theoretical astrophysics , which

2030-593: The expansion of the CfA's observing facilities around the world, including the newly named Fred Lawrence Whipple Observatory , the Infrared Telescope (IRT) aboard the Space Shuttle , the 6.5-meter Multiple Mirror Telescope (MMT), the SOHO satellite , and the launch of Chandra in 1999. CfA-led discoveries throughout this period include canonical work on Supernova 1987A , the " CfA2 Great Wall " (then

2088-544: 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,

2146-476: 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 1980s also saw the CfA play a distinct role in the history of computer science and the internet: in 1986, SAO started developing SAOImage, one of the world's first X11 -based applications made publicly available (its successor, DS9, remains

2204-514: 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 history of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA's founding. These are briefly summarized below. Samuel Pierpont Langley ,

2262-556: The most widely used astronomical FITS image viewer worldwide). During this time, scientists and software developers 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. Charles Alcock , known for

2320-471: 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

2378-455: The physicist, Gustav Kirchhoff , and the chemist, Robert Bunsen , had demonstrated that the dark lines in the solar spectrum corresponded to bright lines in the spectra of known gases, specific lines corresponding to unique chemical elements . Kirchhoff deduced that the dark lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere. In this way it

Harvard–Smithsonian Center for Astrophysics - Misplaced Pages Continue

2436-476: 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 ,

2494-405: The routine work of measuring the positions and computing the motions of astronomical objects. A new astronomy, soon to be called astrophysics, began to emerge when William Hyde Wollaston and Joseph von Fraunhofer independently discovered that, when decomposing the light from the Sun, a multitude of dark lines (regions where there was less or no light) were observed in the spectrum . By 1860

2552-431: 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

2610-487: The solar spectrum with any known elements. He thus claimed the line represented a new element, which was called helium , after the Greek Helios , the Sun personified. In 1885, Edward C. Pickering undertook an ambitious program of stellar spectral classification at Harvard College Observatory , in which a team of woman computers , notably Williamina Fleming , Antonia Maury , and Annie Jump Cannon , classified

2668-627: The source of stellar energy was a complete mystery; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einstein's equation E = mc . This was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity ), had not yet been discovered. In 1925 Cecilia Helena Payne (later Cecilia Payne-Gaposchkin ) wrote an influential doctoral dissertation at Radcliffe College , in which she applied Saha's ionization theory to stellar atmospheres to relate

2726-516: The spectra recorded on photographic plates. By 1890, a catalog of over 10,000 stars had been prepared that grouped them into thirteen spectral types. Following Pickering's vision, by 1924 Cannon expanded the catalog to nine volumes and over a quarter of a million stars, developing the Harvard Classification Scheme which was accepted for worldwide use in 1922. In 1895, George Ellery Hale and James E. Keeler , along with

2784-408: The spectral classes to the temperature of stars. Most significantly, she discovered that hydrogen and helium were the principal components of stars, not the composition of Earth. Despite Eddington's suggestion, discovery was so unexpected that her dissertation readers (including Russell ) convinced her to modify the conclusion before publication. However, later research confirmed her discovery. By

2842-504: 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

2900-440: 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. The collaborative foundation for what would ultimately give rise to

2958-707: 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

SECTION 50

#1732773231674

3016-499: The universe; origin of cosmic rays ; general relativity , special relativity , quantum and physical cosmology (the physical study of the largest-scale structures of the universe), including string cosmology and astroparticle physics . Astronomy is an ancient science, long separated from the study of terrestrial physics. In the Aristotelian worldview, bodies in the sky appeared to be unchanging spheres whose only motion

3074-489: The universe; origin of cosmic rays; general relativity and physical cosmology, including string cosmology and astroparticle physics. Relativistic astrophysics serves as a tool to gauge the properties of large-scale structures for which gravitation plays a significant role in physical phenomena investigated and as the basis for black hole ( astro )physics and the study of gravitational waves . Some widely accepted and studied theories and models in astrophysics, now included in

3132-456: 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 (ADS), for example, has been universally adopted as the world's online database of astronomy and physics papers. Known for most of its history as

3190-488: 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

3248-497: Was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field , then affiliated with 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

3306-406: Was proved that the chemical elements found in the Sun and stars were also found on Earth. Among those who extended the study of solar and stellar spectra was Norman Lockyer , who in 1868 detected radiant, as well as dark lines in solar spectra. Working with chemist Edward Frankland to investigate the spectra of elements at various temperatures and pressures, he could not associate a yellow line in

3364-448: Was uniform motion in a circle, while the earthly world was the realm which underwent growth and decay and in which natural motion was in a straight line and ended when the moving object reached its goal . Consequently, it was held that the celestial region was made of a fundamentally different kind of matter from that found in the terrestrial sphere; either Fire as maintained by Plato , or Aether as maintained by Aristotle . During

#673326