The Smithsonian Astrophysical Observatory, founded in 1890, is a research center of the Smithsonian Institution. In 1955, the observatory moved to Cambridge, Mass., and became affiliated with the Harvard College Observatory. In that era, the observatory created the world’s first
satellite-tracking network, establishing the organization as a pioneer in space science research. In 1973, the Smithsonian and Harvard created the joint Harvard-Smithsonian Center for Astrophysics.
Key Areas of Research at the Center
Exoplanets—In the past two decades, new discoveries have improved the understanding of other planetary systems. By measuring the brightnesses and motions of nearby stars, astronomers have detected more than 2,000 planets in 1,330 planetary systems. Most planets are gas giants like Jupiter or Neptune. Others are rocky super-Earths or Earth-sized worlds. SAO scientists use ground-based and space-based instruments to detect and characterize exoplanets. In particular, SAO is playing a major role in NASA’s Kepler mission to search for habitable Earth-like planets.
The Sun and Solar Weather—SAO scientists study the sun to learn about the day-to-day behavior of an ordinary star, which includes giant magnetic storms that eject high-energy particles into the solar system. The observatory also has developed computer models that may one day help forecast these storms and warn astronauts.
Star and Planet Formation—When people look up at the sky at night, they see light produced by stars. Stars form in large clouds of gas and dust. Planets grow in the circumstellar disk that surrounds every newborn star. To learn how stars form, SAO scientists study the structure of dark cosmic clouds and the young stars within the clouds. To study the birth of planets, SAO scientists examine the structure of circumstellar disks and outflowing jets associated with the youngest stars.
The Extreme Universe—The universe contains strange objects and explosions that dwarf anything that can be produced by an Earth-bound laboratory. Most of these “extremes” were only recognized as astronomy extended its reach beyond the visible light people can see, across the whole, vastly larger, spectrum, from radio to X-rays. SAO scientists study extremes of density, temperature, magnetic field and rapid energy release. The types of object they study include black holes, pulsars, supernovae, white dwarfs, neutron stars and magnetars.
Asteroids and Comets—The formation of planets is a key part of the history of Earth’s solar system. “Leftovers” from this cosmic construction process—comets and asteroids—can provide vital clues to the earliest epochs. Observatory scientists formulated the modern theory of cometary composition and structure. They also determine and refine asteroidal and cometary orbits to watch for potential impactors.
Chandra X-ray Observatory—NASA’s Chandra X-ray Observatory is the most sophisticated X-ray observatory ever built, providing images 25 times sharper than previous pictures. When launched in 1999, Chandra joined the Hubble Space Telescope as one of NASA’s “Great Observatories.” Chandra observes X-rays from high-energy processes taking place throughout the universe, allowing more detailed studies of black holes, supernovae and dark matter. Chandra is operated by the observatory from a control center in Cambridge.
Solar Dynamics Observatory—The Solar Dynamics Observatory (SDO) is a NASA mission that has been observing the sun since 2010. The goal of the SDO is to understand the influence of the sun on the Earth and near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously. It carries the Atmospheric Imaging Assembly, an instrument that SAO helped Lockheed-Martin to design and build. The instrument takes photos of the full sun every 12 seconds with an image size of 4096-by-4096 pixels. By comparison, a high-definition TV can only display 1920-by-1080 pixels.
Spitzer Space Telescope—NASA’s Spitzer Space Telescope, launched in 2003, is the fourth and last of NASA’s “Great Observatories.” Spitzer collects infrared radiation from the youngest and most distant galaxies in the universe, as well as from cold and dusty regions within the Milky Way. Spitzer’s Infrared Array Camera, developed by observatory scientists, was the first instrument to directly detect light from a planet orbiting a distant star. It continues to be used to characterize planets detected by other observatories like Kepler.
Submillimeter Array—The world’s first submillimeter array (SMA), dedicated in November 2003, consists of eight 6-meter (20-foot) diameter movable antennas located on Mauna Kea, Hawaii. The SMA makes high-resolution observations in the little-explored submillimeter region of the electromagnetic spectrum. It was designed to study star-forming regions, molecular clouds, quasars and active galactic nuclei. The SMA is a collaboration between the observatory and the Institute of Astronomy and Astrophysics of the Academia Sinica of Taiwan.
Fred Lawrence Whipple Observatory—Located 35 miles south of Tucson, Ariz., at Mount Hopkins, the Fred Lawrence Whipple Observatory is the largest field station of the Smithsonian Astrophysical Observatory. The observatory’s facilities include an array of four 12-meter (39-foot) gamma-ray telescopes called the Very Energetic Radiation Imaging Telescope Array System (VERITAS). Whipple Observatory also is home to a 1.3-meter (51-inch) infrared telescope, a 1.2-meter (48-inch) imaging optical/infrared telescope, the HAT (Hungarian Automated Telescope) network of planet-hunting telescopes, the MEarth array of planet-hunting telescopes and the 1.5-meter (60-inch) Tillinghast spectroscopic telescope.
MMT Observatory—The MMT, located on the summit of Mount Hopkins, initially consisted of a system of six 1.8-meter (72-inch) telescopes on a single mount. It was converted to house a single
6.5-meter (21-foot) mirror possessing more than twice the light-gathering power of the original MMT and able to view an area of sky about 400 times larger. Its state-of-the-art instruments include Megacam, a 6-megapixel camera capable of taking stunning astronomical portraits, and Hectospec, a spectrograph that can analyze light from 300 galaxies at once. The Smithsonian Astrophysical Observatory operates the MMT jointly with the University of Arizona.
South Pole Telescope—This 10-meter (33-foot) telescope is designed to conduct large-area surveys of faint, low-contrast millimeter and submillimeter emission. Because of its exceptionally cold and dry atmosphere, the South Pole is arguably the best ground-based site for observations at submillimeter wavelengths. This telescope will help scientists learn about the mysterious dark-energy phenomenon that is speeding up the expansion of the universe.
Budget and Staff
he observatory’s fiscal year 2015 budget was approximately $140 million. The Harvard-Smithsonian Center for Astrophysics comprised more than 900 people in 2015—some 200 with a Harvard affiliation and approximately 700 with a Smithsonian affiliation, including SAO staff scientists, engineers, technical staff, administrators and educators, as well as visiting scientists, postdoctoral fellows and graduate students.
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