The Simons Foundation has awarded a $38.4 million grant to establish the Simons Observatory, a new astronomy facility in Chile’s Atacama Desert that will merge and expand existing efforts to explore the evolution of the universe from its earliest moments to today. An additional $1.7 million of support is being provided by the Heising-Simons Foundation.

The project is a collaboration between the University of Pennsylvania; Princeton University; the University of California, San Diego; the University of California, Berkeley; and the Lawrence Berkeley National Laboratory, all of which are also providing financial support.

This project will investigate cosmic microwave background radiation to better understand the physics of the big bang, the nature of dark energy and dark matter, the properties of neutrinos and the formation of structure in the universe.

“A key target of this observatory is the earliest moments in the history of the universe,” said Mark Devlin, the Reese W. Flower Professor of Astronomy and Astrophysics in Penn’s School of Arts & Sciences and current project spokesperson.

“While patterns that we see in the microwave sky are a picture of the structure of the universe 380,000 years after the Big Bang, we believe that some of these structures were generated much earlier, by gravitational waves produced in the first moments of the universe’s expansion,” he said. “By measuring how the gravitational waves affect electrons and matter 380,000 years after the big bang we are observing fossils from the very, very early universe.”

Devlin’s research is primarily in the area of cosmology and the evolution of structure in the universe as well as extra-galactic and galactic star formation. His group specializes in the design and construction of novel telescopes and cryogenic receivers operating at millimeter and sub-millimeter wavelengths. Devlin is the co-director of the Atacama Cosmology Telescope and the primary investigator for the Balloon-borne Large Aperture Telescope, or BLAST, and the MUSTANG instrument in the Green Bank Telescope. 

The extraordinarily rapid expansion of space during “inflation,” an epoch posited in the most popular cosmological theory, generated gravitational waves. These would have induced a very small but characteristic polarization pattern in the CMB at radio wavelengths that can be detected by specially designed telescopes and cameras.  

A detection of this type of signal, known as “B-mode polarization,” would measure the energy scale associated with inflation, which could be as much as a trillion times higher than the energy accessible in the largest particle accelerators. A detection could also provide evidence for a link between quantum mechanics and gravity. Understanding the link between these two powerful theories is the focus of string theorists and others studying fundamental physics.

“The generosity of this award is unprecedented in our field and will enable a major leap in scientific capability” said UC San Diego astrophysicist Brian Keating, the project director. “People are used to thinking about mega- or giga-pixel detectors in optical telescopes, but for signals in the microwave range 10,000 pixels is a lot. What we’re trying to do — the real revolution here — is to pave the way to increase our pixels number by more than an order of magnitude.”

In addition to searching for B-mode polarization, the Simons Observatory will study how the light from the CMB is deflected by the intervening structure in the universe. These measurements will provide unique insights into basic questions including the masses of the neutrinos, the nature of dark energy and dark matter and the physics that governed the formation of cosmic structure as the universe evolved after the big bang.

The Simons Observatory will also identify thousands of clusters of galaxies, the largest gravitationally bound objects in the universe. Where and when these massive objects formed is a strong function of the same set of cosmological parameters, providing an independent check of their values.

The Simons Observatory is designed to be a first step toward an ultimate experiment aimed at extracting the full measure of cosmological information in the cosmic microwave background fluctuations accessible from the ground. The experiment is called CMB-Stage 4, or CMB-S4, referring to the fourth stage or generation of experiment.  This next-generation experiment builds on years of support from the National Science Foundation, and the Department of Energy has recently announced its intent to participate in CMB-S4. It is envisioned to have telescopes at multiple sites and draw together a broad community of experts from the United States and abroad. The Atacama site in Chile has already been identified as an excellent location for CMB-S4, and the Simons Foundation funding will help develop it for that role.

The site in Chile is located in the Parque Astronómico, which is administered by the Comisión Nacional de Investigación Científica y Tecnológica, or CONICYT.  Since 1998, U.S. investigators and the NSF have worked with Chilean scientists, the University of Chile and CONICYT to locate multiple projects at this high, dry site to study the CMB.