Penn State joins new project to map the Universe

Penn State is an institutional partner in a new effort to investigate the structure of our galaxy, the evolution of nearby galaxies and the nature of dark energy. The effort is the newest phase of the Sloan Digital Sky Survey (SDSS-IV), an international collaboration of more than 200 astronomers at more than 40 institutions.

"The SDSS has been one of the most productive endeavors in the history of astronomy, and it provides exciting scientific opportunities to Penn State faculty and students," said Donald Schneider, head of the Department of Astronomy and Astrophysics.

The SDSS-IV survey has three primary scientific programs. The first is to explore the compositions and motions of stars across the entire Milky Way in unprecedented detail. SDSS-IV will use an instrument that is sensitive to infrared light to peer through the dust in our galaxy to investigate the properties of over 100,000 stars in our own galaxy.

"The unique capabilities of the infrared instrument will help us to understand the dynamics and compositions of stellar populations in our galaxy, binary stars, and the properties of planet-hosting stars discovered by the Kepler mission," said Assistant Professor of Astronomy and Astrophysics Suvrath Mahadevan.

In addition to the Sloan Foundation's 2.5-meter telescope in New Mexico, SDSS-IV will obtain observations with the 2.5-meter Irinie du Pont telescope at Las Campanas Observatory, high in the Chilean Andes, where the skies are among the clearest on Earth. The Chilean telescope will allow a full study of the Milky Way, reaching areas of the sky that are inaccessible from New Mexico. It also will be used to investigate of the Magellanic Clouds -- nearby dwarf galaxies that are always below the horizon in New Mexico.

The second program of SDSS-IV also will improve our understanding of the large-scale structure of the universe. The survey will measure the expansion history of the universe through 80 percent of cosmic history, back to times when the universe was less than 3 billion years old. These detailed measurements will improve constraints on the nature of dark energy, the most mysterious experimental result in modern physics.

"These observations of distant objects also will extend greatly our ability to monitor the variations of the emission from quasars, providing insights into how quasar winds, which have speeds of millions of miles per hour, are created," said Niel Brandt, Distinguished Professor of Astronomy and Astrophysics. "These violent motions, ultimately powered by material falling into supermassive black holes, are crucial to our understanding of the growth of black holes and the evolution of their host galaxies."

Sloan Foundation 2.5m Telescope

Changing a cartridge, opening the enclosure, sunset, and nightly observing at the Sloan Foundation 2.5m Telescope at Apache Point Observatory, Sunspot, New Mexico. During the night, an observer changes the cartridge to observe a new set of stars or galaxies roughly every hour. Each cartridge contains hundreds of fiber-optic cables plugged into holes in a large aluminum plate. Each fiber observes a single star or galaxy. The "bright time" observing is during a nearly full moon, the "dark time" is before moonrise, with the moon (not the sun!) rising shortly before the end of the video. The orange glow in the background is from the city of El Paso, Texas, 90 miles to the south. The multi-colored lights briefly shining through the telescope petals before and after cartridge changes are calibration sequences. We use different light sources to check that all parts of the instrument see light the same way and to compare the observations to known standards.  

Music from "Just Ancient Loops" Composed by Michael Harrison, Cellos performed by Maya Beiser From the Cantaloupe Music CD Time Loops. Video: Sloan Digital Sky Survey

SDSS-IV will use innovative new technology to produce detailed maps of thousands of nearby galaxies. Construction of these maps now is made possible with a new technique for bundling sets of fiber-optic cables into tightly packed arrays. These fiber arrays collect light from across the entire extent of a galaxy, enabling detailed spectral measurements during the duration of the SDSS-IV project of more than 10,000 nearby galaxies.

"Our goal is to understand the 'life cycle' of present-day galaxies from imprinted clues of their birth and assembly, through their ongoing growth via star formation and merging, to their eventual fade-out after star formation ends," said Matt Bershady of the University of Wisconsin, the SDSS-IV project scientist.

With the enhanced capabilities of its powerful instruments, a new outpost in the Southern Hemisphere and the continuing support of the Alfred P. Sloan Foundation, the SDSS continues to be one of the world's most productive astronomical facilities. Penn State astronomers, and others worldwide, anticipate that science results from the SDSS will continue to reshape our view of the fundamental constituents of the cosmos.


Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation and the participating institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is

SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofisica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut fur Astrophysik Potsdam (AIP), Max-Planck-Institut fur Astrophysik (MPA Garching), Max-Planck-Institut fur Extraterrestrische Physik (MPE), Max-Planck-Institut fur Astronomie (MPIA Heidelberg), National Astronomical Observatory of China, New Mexico State University, New York University, The Ohio State University, Penn State, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autonoma de Mexico, University of Arizona, University of Colorado Boulder, University of Portsmouth, University of Utah, University of Washington, University of Wisconsin, Vanderbilt University and Yale University.

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Last Updated August 13, 2014