Allen Telescope Array (ATA) Nighttime Horizontat. Image Courtesy SETI Institute.
On November 20, 2024, the SETI (Search for Extraterrestrial Intelligence) Institute celebrated the exact day of its incorporation in 1984, marking its 40th anniversary of searching for signs of extraterrestrial life. The gala event, at a Menlo Park, California golf resort and presided over by president/chief executive Bill Diamond, SETI included the announcement of a new award in honor of pioneering radio astronomer and Institute cofounder Dr. Jill Tarter, who was also the inaugural recipient of the award. Tarter initially served a project scientist for NASA’s SETI program, the High Resolution Microwave Survey, at the NASA Ames Research Center in the early 1980s, and established the SETI Institute as a nonprofit research center to lower costs for NASA. Dr. Tarter led the effort to build the Institute’s radio telescope, the Allen Telescope Array, which was commissioned in 2007. She currently serves on the Institute’s Board of Directors and its Science Advisory Board. (As an aside, Tarter inspired Jodie Foster’s character in the 1997 movie Contact, based on a book by Carl Sagan.)
“The Institute has been engaged in its namesake endeavor since its founding,” says Diamond. “Federal funding was terminated for SETI programs in 1992. The Institute expanded research to include astrophysics, planetary science and astrobiology to maintain NASA funding.” Since then, pure SETI research has been funded by private investment and philanthropy — a more volatile economic base. In 2015, Diamond was brought on board to strengthen the financial picture.
The SETI Institute is made up of a deep bench of scientists, most of whom work on projects unrelated to the organization’s namesake activity — the search for intelligent life. One of the few full-time SETI scientists is Dr Andrew Siemion, who holds the Bernard M Oliver Chair for SETI Research. Siemion, who got his Ph.D. in Astrophysics at UC Berkeley, joined the SETI Institute in 2018 while simultaneously serving as principal investigator of the Breakthrough Listen program, the most comprehensive extraterrestrial signal search in history. The program covers the Northern Hemisphere (out of Green Bank Observatory in West Virginia) and the Southern Hemisphere (from Parkes Observatory in Australia), as well as visible light observations from the Automated Planet Finder, a robotic optical telescope at Lick Observatory east of San Jose, California. Breakthrough Listen is now headquartered at the University of Oxford, but Siemion says, it is “conducted in close collaboration with a variety of international partners, preeminent among them the SETI Institute.”
In 2018, Siemion took charge of the transformation of the Allen Telescope Array (ATA), located at the Hat Creek Radio Observatory in northern California. The ATA had been the first radio telescope designed from the ground up to be used specifically for SETI searches. Today SETI combines the ATA’s capabilities with a new program on the National Science Foundation’s Karl G Jansky Very Large Array (VLA), a collection of 27 radio telescopes over 22 miles in New Mexico. In collaboration with the National Radio Astronomy Observatory and the Breakthrough Listen Initiative, the result — powered by SETI’s processing program COSMIC (Commensal Open-Source Multimode Interferometer Cluster) — will be “approximately a thousand times more comprehensive than any previous SETI search.”
Artificial intelligence and accelerated computing with NVIDIA GPUs are other new technologies that have dramatically expanded SETI’s ability to analyze streaming astronomical data, says Siemion. After first using NVIDIA GPUs to accelerate the algorithms to separate signals from background noise, Siemion’s team built a trial application with NVIDIA Holoscan, a sensor processing platform for processing real-time data from scientific instruments. “It was clear from the beginning that Holoscan was going to be a very useful piece of technology for us,” he says “We wanted to build a way to detect fast radio bursts — millimeter scale of radio energy approximately equal to the amount of energy the sun releases in an entire year.” Some of these fast radio bursts are one-off events, he adds, “but sometimes you get repeated bursts from the source.” That summer, the SETI Institute became the first to build a pure AI inference pipeline to look for these fast radio bursts.” In a test, they team linked the real-time Holoscan pipeline to 28 antennas pointing at the Crab Nebula. In 15 hours, they gathered 90+ billion data packets on signals across a spectrum of 5GHz, capturing and analyzing in real time nearly the full 100 Gbps of data “It’s a profound change in how radio astronomy is done,” says Siemion. “This was a small test and now we’ll be rolling it out to other telescopes over the next 18 to 24 months. We hope our success will help build adoption and enthusiasm across all radio astronomy.”
Optical/LaserSETI is another ongoing program expanding the reach of the SETI Institute, headed by scientist Eliot Gillum who joined the Institute in 2015 to develop a new type of instrument. “LaserSETI was conceived to be the first all-sky, all-the-time optical SETI survey,” he says. “The idea of looking everywhere all the time is really revolutionary, especially given that there are 400 billion stars in the galaxy and billions of galaxies. And an awful lot of space in between.”
What LaserSETI is looking for are short-burst laser signals, which would be a likely means for advanced societies to communicate. “Lasers focus energy a million times better than radio, just by virtue of the wavelength,” Gillum explains. “If you’re using it for communication or to propel a spacecraft, it’s a signal that projects farther.”
Historically, optical SETI instruments have all been based on photomultiplier tubes — essentially one-pixel cameras — to detect flashes. Based on an idea by Santa Barbara Instrument Group’s Alan Holmes, Gillum evolved the concept into a new device which can image about 75-degree-field of view — about a fifth of the sky visible from the surface of the Earth. A transmission grating makes it easy for the software to filter out anything that’s not a laser.
In its first phase, LaserSETI set up two instruments at the Ferguson Observatory in Sonoma County in California and two at Haleakala on Maui in Hawaii, both looking at the same parts of the sky, covering a combined 18 percent of the entire night sky. But the project is already expanding further. In August 2024, the SETI Institute team installed two new LaserSETI stations in Sedona, Arizona, bringing coverage to 31 percent. According to Gillum, nine more stations are under construction — with observatories in the Caribbean, the Arabian Peninsula, Europe and the Himalayas — which will bring sky coverage to 58 percent.
At the SETI Institute Carl Sagan Center for Research, director Nathalie A. Cabrol spearheads a multidisciplinary roadmap to bridge astrobiology (her expertise) and SETI’s astrophysics’ emphasis. “The search for extraterrestrial life can range from the origins of life to the search for advanced civilizations,” she says. “They are all under the umbrella of the coevolution of life and its environments.” She notes that astrobiology has always been part of the SETI Institute’s area of interest, as represented by the Drake Equation, posited by astronomer/SETI pioneer Frank Drake in 1961 to estimate the number of communicating advanced civilizations elsewhere in the Milky Way galaxy.
The presence of such societies implies an answer to the questions of what environments are favorable to the development of life — and where we might find it, she explains. “It was the first astrobiology roadmap,” says Cabrol. The field of astrobiology took off in the 1990s, and she adds, now is accounting for a substantial part of what the Carl Sagan Center for Research does.
In addition to astronomy and astrophysics-oriented research, another research division at the Carl Sagan Center for Research focuses on exoplanets, which are planets that orbit stars outside of our solar system; NASA has confirmed more than 5,600 exoplanets but billions are believed to exist. “We’ve been busy detecting exoplanets and doing data analytics and archival work,” Cabrol says. “Our scientists in that division are very involved with ground and space telescopes searching for exoplanets.” Planetary exploration is another research division. “The SETI Institute is involved in whatever has been flying or will be flying in the solar system,” she says. Some examples are a NASA/SETI collaboration on instruments on the Curiosity Mars Rover; another scientist is involved with the Raman-LIBS on the Perseverance Mars Rover.
Research also takes scientists into the field. For the past 20 years, Cabrol has been leading multidisciplinary and international field expeditions in the highest altitudes of the South American Andes supported by the NASA Astrobiology Institute and other NASA astrobiology programs. There, with her team, she develops new planetary exploration strategies, instruments, and systems that will change the way we search for life beyond Earth.
The Carl Sagan Center for Research is complemented by the Center for Education and Outreach, led by the Carl Sagan Center’s deputy director Dr. Simon Steel. As such, he is responsible for the SETI Institute’s NASA Community College Network (NCCN), an initiative to bring NASA Subject Matter Experts, research findings and science sources into community colleges throughout the U.S. The five-year program started on January 1, 2021, and currently connects over 216 community colleges across 41 states, via more than 100 subject matter experts from major universities, observatories and NASA centers.
“About 300,000 students take introductory astronomy every year and almost half of those are studying at a community college,” says Steel. “This is probably the last science course any of them will take. Astronomy is a way to inspire students, but also to build science literacy. There’s a strong importance to giving students an ability to think scientifically.” The program helps community college instructors navigate and access NASA assets. “The need can be very last minute,” says Steel. “An instructor may want to talk about, say, Europa Clipper that just came up on the news and wants to know what NASA resources are at hand.”
Although not all community colleges need such resources, Steel says that the Center for Education is now focused on supporting community colleges in rural states and native reservations. “I had the opportunity to visit the Crow Nation and North Cheyenne Nations, which are teaching with incredibly low resource levels,” he says. “Working with tribal communities is a new and essential part of the program. We tie astronomy in with their cultures’ cosmology and science, which enhances both stories.” A major goal of the Institute, he says, is to engage with indigenous peoples globally in asking the biggest questions of science and the universe.”
Another major NASA-funded program is to provide professional development to high school teachers. “We teach the electromagnetic spectrum, to understand light and what it tells us about the universe,” says Steel. “We provide the background material and immersive experiences in a research environment.” Some go on trips to observatories, such as Mt. Wilson and Lick Observatory. “We’ve measured and quantified that this [training of teachers] leads to increased performance by their students.”
SETI is an easy sell to educators and their students, says Steel. “Everyone is excited about it. And, importantly, SETI is equally appealing to both genders and most cultures.”
According to Diamond, the future of SETI’s pure research looks bright. In 2022, Qualcomm cofounder and engineer Franklin Antonio, who had been an ardent SETI supporter, died — and left a $200 million gift to the organization. “It has truly been a game changing phenomenon” says Diamond. “SETI Research now has a solid financial foundation, and Franklin’s gift has allowed for transformative new programs, including postdoctoral research fellowships, internal funding for our own science proposals, global funding for innovative SETI research elsewhere, and new initiatives for education and outreach. The Institute has been transformed over the last several years in terms of where we go from here.” With the discovery of the ubiquity of exoplanets and habitable worlds, the search for life beyond Earth has moved from a side question in space science and exploration to become the central question. “New telescopes, greater global engagement, new missions and advanced data analytics are bringing us ever closer to finally answering that question,” says Diamond. “And when we do, it will change humanity forever — and — raise a thousand new questions!”