SETI Archives

September 20, 2023September 20, 2023 by Matt Williams

We Should Be Looking for Small, Hot Dyson Spheres

A Type II civilization is one that can directl harvest the energy of its star using a Dyson Sphere or something similar. Credit: Fraser Cain (with Midjourney)

In 1960, legendary physicist Freeman Dyson published his seminal paper “Search for Artificial Stellar Sources of Infrared Radiation,” wherein he proposed that there could be extraterrestrial civilizations so advanced that they could build megastructures large enough to enclose their parent star. He also indicated that these “Dyson Spheres,” as they came to be known, could be detected based on the “waste heat” they emitted at mid-infrared wavelengths. To this day, infrared signatures are considered a viable technosignature in the Search for Extraterrestrial Intelligence (SETI).

So far, efforts to detect Dyson Spheres (and variation thereof) by their “waste heat” signatures have come up empty, leading some scientists to recommend tweaking the search parameters. In a new paper, astronomy and astrophysics Professor Jason T. Wright of the Center for Exoplanets and Habitable Worlds and the Penn State Extraterrestrial Intelligence Center (PSTI) recommends that SETI researchers refine the search by looking for indications of activity. In other words, he recommends looking for Dyson Spheres based on what they could be used for rather than just heat signatures.

September 20, 2023September 20, 2023 by Brian Koberlein

First Contact Could Turn Out Well for Humanity

Illustration of a radio telescope listening for signals from an alien civilization. Credit: Zayna Sheikh, Breakthrough Listen

You’ve heard this story before. An advanced alien race comes to Earth. They offer peace and prosperity, but they hold a dark secret. One that could destroy humanity. That dark secret has varied over the years, from stealing our water, books on culinary advice, or communism, but the result is always the same. First contact with advanced extraterrestrials goes very badly for us. But in reality, how bad could it be? That’s the question a new study examines using game theory and Hobbesian philosophy.

September 1, 2023September 1, 2023 by Evan Gough

Is Anyone Planning for Diplomacy with an Extraterrestrial Civilization?

Artist impression of an alien civilization. Image credit: CfA

Imagine we detect an interstellar object entering our Solar System. At first, astronomers think it’s just another natural interloper like Oumuamua or comet Borisov. We’re warming up to the idea of visitors from other parts of the galaxy, though they’ve been inanimate so far.

But then, what if it becomes clear that something’s different about this visitor? What if it moves unnaturally or somehow behaves purposefully? What if it takes up a stable orbit somewhere? What if, as we gather more evidence, it becomes clear that it’s a probe of some sort sent to us intentionally? What if it communicates with us?

Suddenly, as if thrust into a science fiction plot, humanity is in a totally different situation. What do we do?

August 15, 2023August 21, 2023 by Matt Williams

The 2nd Annual Penn State SETI Symposium and the Search for Technosignatures!

Artist's impression of a Dyson Sphere, an proposed alien megastructure that is the target of SETI surveys. Finding one of these qualifies in a "first contact" scenario. Credit: Breakthrough Listen / Danielle Futselaar

From June 18th to 22nd, the Penn State Extraterrestrial Intelligence Center (PSETI) held the second annual Penn State SETI Symposium. The event saw experts from many fields and backgrounds gathering to discuss the enduring questions about SETI, the technical challenges of looking for technosignatures, its ethical and moral dimensions, and what some of the latest experiments have revealed. Some very interesting presentations examined what will be possible in the near future and the likelihood that we will find evidence of extraterrestrial intelligence.

Among them, there were some very interesting presentations by Adam Frank, Professor of Astrophysics at the University of Rochester; Ph.D. student Matias Suazo, an astrophysicist and member of Project Haephestos at the University of Uppsala; and Nicholas Siegler, the Chief Technologist of NASA’s Exoplanet Exploration Program (ExEP). These presentations addressed ongoing issues in the search for extraterrestrial intelligence (ETI), technosignatures, the role of oxygen in the evolution of complex life, and what motivations extraterrestrial civilizations (ETC) might have for creating noticeable signatures.

August 9, 2023April 14, 2024 by Matt Williams

Penn State SETI Symposium Opens with Commemoration of Dr. Frank Drake

Dr. Frank Drake (1930 -2022). Credit: Danielle Futselaar

Is humanity alone in the Universe? Is anyone out there? Where is everybody? And what happens if and when we make contact with them? These and other questions were the subjects of the 2023 Penn State SETI Symposium hosted by the Penn State Extraterrestrial Intelligence Center (PSETI) from June 19th-22nd, 2023. The event featured prominent speakers from various research fields and disciplines discussing the challenges, history, and future of SETI. In the great tradition established by Dr. Frank Drake, they also addressed key issues related to the search for intelligent life and what we might find someday.

The summit opened with a series of overviews, a review of the past year (since the last summit), and a presentation by Dr. Rebecca Charbonneau, a science historian and Jansky Fellow at the National Radio Astronomy Observatory (NRAO). Her presentation, titled “Frank Drake and his Place in History,” provided a retrospective on the life and accomplishments of famed radio astronomer and SETI pioneer Dr. Frank Drake (for whom the Drake Equation is named), how he altered the character of the field, and how history will remember him.

August 2, 2023August 2, 2023 by Matt Williams

Variable Stars can Tell us Where and When to Search for Extraterrestrials

Artist’s impression of the Gaia spacecraft detecting artificial signals from a distant star system. In this synchronization scheme, the star system's inhabitants send the signal shortly after witnessing a supernova, which is also seen by telescopes on Earth. (Credit: Danielle Futselaar / Breakthrough Listen)

The European Space Agency’s Gaia Observatory has been operating steadily at the Earth-Sun L2 Lagrange Point for almost a decade. As an astrometry mission, Gaia aims to gather data on the positions, proper motion, and velocity of stars, exoplanets, and objects in the Milky Way and tens of thousands of neighboring galaxies. By the end of its primary mission (scheduled to end in 2025), Gaia will have observed an estimated 1 billion astronomical objects, leading to the creation of the most precise 3D space catalog ever made.

To date, the ESA has conducted three data releases from the Gaia mission, the latest (DR3) released in June 2022. In addition to the breakthroughs these releases have allowed, scientists are finding additional applications for this astrometric data. In a recent study, a team of astronomers suggested that the variable star catalog from the Gaia Data Release 3 could be used to assist in the Search for Extraterrestrial Intelligence (SETI). By synchronizing the search for transmissions with conspicuous events (like a supernova!), scientists could narrow the search for extraterrestrial transmissions.

July 8, 2023July 8, 2023 by Matt Williams

Astronomers Scan the Skies for Nanosecond Pulses of Light From Interstellar Civilizations

Artist’s impression of Green Bank Telescope connected to a machine learning network. Credit: Breakthrough Listen/Danielle Futselaar.

In 2015, Russian-Israeli billionaire Yuri Milner and his non-profit organization, Breakthrough Initiatives, launched the largest Search for Extraterrestrial Intelligence (SETI) project. Known as Breakthrough Listen, this SETI effort relies on the most powerful radio telescopes in the world and advanced analytics to search for potential evidence of technological activity (aka. “technosignatures”). The ten-year project will survey the one million stars closest to Earth, the center of our galaxy, the entire galactic plane, and the 100 galaxies closest to the Milky Way.

In 2018, they partnered with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Collaboration, a ground-based system of gamma-ray telescopes operating at the Fred Lawrence Whipple Observatory (FLWO) atop Mt. Hopkins in southern Arizona. In a recent paper, the VERITAS Collaboration shared the results of the first year of their search for “optical technosignatures” (from 2019 to 2020). Their results are a vital proof of concept demonstrating how future searches for extraterrestrial civilizations can incorporate optical pulses into their technosignature catalog.

June 17, 2023June 17, 2023 by Scott Alan Johnston

We Could See the Glint off Giant Cities on Alien Worlds

How large would an extraterrestrial city have to be for current telescopes to see it? Would it need to be a planet-sized metropolis like Star Wars’ Coruscant? Or could we see an alien equivalent of Earth’s own largest urban areas, like New York City or Tokyo?

A recent preprint by Bhavesh Jaiswal of the Indian Institute of Science suggests that, in fact, we could see cities a mere fraction of that size, using a feature of light known as specular reflection.

June 2, 2023June 6, 2023 by Matt Williams

Astronomers are Searching for a Galaxy-Wide Transmitter Beacon at the Center of the Milky Way

It has been over sixty years since the first Search for Extraterrestrial Intelligence (SETI) survey occurred. This was Project Ozma, a survey led by Dr. Frank Drake (who devised the Drake Equation) that used the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia, to listen for radio transmissions from Epsilon Eridani and Tau Ceti. While the search revealed nothing of interest, it paved the way for decades of research, theory, and attempts to find evidence of technological activity (aka. “technosignatures”).

The search continues today, with researchers using next-generation instruments and analytical methods to find the “needle in the cosmic haystack.” This is the purpose behind Breakthrough Listen Investigation for Periodic Spectral Signals (BLIPSS), a collaborative SETI project led by Cornell graduate student Akshay Suresh to look for technosignatures at the center of the Milky Way. In a recent paper, Suresh and his team shared their initial findings, which were made possible thanks to data obtained by the Greenbank Observatory and a proprietary algorithm they developed.

May 30, 2023May 30, 2023 by Matt Williams

A Sign from Space Simulates What it Would be Like to Get a Message from Aliens!

A Sign in Space is a worldwide artistic project that will inspire a conversation about the possibility of First Contact. Credit: SETI Institute

Someday, humanity might receive a message from space that will answer one of the greatest existential questions: is anybody out there? Regardless of the content, a message from an extraterrestrial civilization will be the single greatest event in human history. How would such an event happen, and how would it play out? What will be the repercussions of billions of people suddenly learning that we are NOT alone in the Universe? This question has inspired countless works of science fiction and scientific studies that have attempted to predict (and even quantify) our collective reaction.

This was the purpose behind A Sign in Space, a revolutionary art project designed to simulate a First Contact scenario. This project was the brainchild of Daniela de Paulis, a contemporary artist, and licensed radio operator currently serving as the Artist in Residence at the SETI Institute and the Green Bank Observatory. Together with a team of international experts, including SETI researchers, space scientists, and artists, de Paulis created this campaign to engage the global SETI community and the general public about the possibility of First Contact.