An illustration of cosmic expansion. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab
In 1960, in preparation for the first SETI conference, Cornell astronomer Frank Drake formulated an equation to calculate the number of detectable extraterrestrial civilizations in our Milky Way. Rather than being a scientific principle, the equation was intended as a thought experiment that summarized the challenges SETI researchers faced. This became known as the Drake Equation, which remains foundational to the Search for Extraterrestrial Intelligence (SETI) to this day. Since then, astronomers and astrophysicists have proposed many updates and revisions for the equation.
This is motivated by ongoing research into the origins of life on Earth and the preconditions that led to its emergence. In a recent study, astrophysicists led by Durham University produced a new model for the emergence of life that focuses on the acceleration of the Universe’s expansion (aka. the Hubble Constant) and the number of stars formed. Since stars are essential to the emergence of life as we knot it, this model could be used to estimate the probability of intelligent life in our Universe and beyond (i.e., in a multiverse scenario).
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.
The Stephans Quintet captured by the James Webb Space Telescope (JWST). Credit: NASA/ESA/CSA
It has been over sixty years since Dr. Frank Drake (father of the Drake Equation) and his colleagues mounted the first Search for Extraterrestrial Intelligence (SETI) survey. This was known as Project Ozma, which relied on the “Big Ear” radio telescope at the National Radio Astronomy Observatory (NRAO) in Greenbank, West Virginia, to look for signs of radio transmissions in Tau Ceti and Epsilon Eridani. Despite the many surveys conducted since then, no definitive evidence of technological activity (i.e., “technosignatures”) has been found.
This naturally raises the all-important question: are we going about the business of SETI wrong? Instead of looking for technosignatures within our galaxy, as all previous SETI surveys have done, should we look for activity beyond our galaxy (from possible Type II and Type III civilizations)? This premise was explored in a recent paper led by researchers from the National Chung Hsing University in Taiwan. Using data from the largest SETI project to date, Breakthrough Listen, the team looked for potential radio technosignatures from extragalactic sources.
Frank Drake by the Tatel Telescope at the Green Bank Observatory. Credit: NRAO/NSF/AUI
Legendary astronomer Frank Drake has passed away at the age of 92. Known primarily for his Drake Equation — an estimate of the probability of intelligent extraterrestrial life — he pioneered the field of SETI, the Search for Extraterrestrial Intelligence, and was a noted astronomer and astrophysicist. His work and life have left an indelible mark on humanity and given hope and wonder to all our hearts.
For over sixty years, scientists have been searching the cosmos for possible signs of radio transmission that would indicate the existence of extraterrestrial intelligence (ETI). In that time, the technology and methods have matured considerably, but the greatest challenges remain. In addition to having never detected a radio signal of extraterrestrial origin, there is a wide range of possible forms that such a broadcast could take.
In short, SETI researchers must assume what a signal would look like, but without the benefit of any known examples. Recently, an international team led by the University of California Berkeley and the SETI Institute developed a new machine learning tool that simulates what a message from extraterrestrial intelligence (ETI) might look like. It’s known as Setigen, an open-source library that could be a game-changer for future SETI research!
A team of astronomers from UCLA searched for "technosignatures" in the Kepler field data. Credit and Copyright: Danielle Futselaar
On November 16th, 1974, a coded radio message was broadcast from the Arecibo Observatory in Puerto Rico. The message contained information on mathematics, humanity, the Solar System, DNA, and the Observatory itself. The destination for this message was Messier 13 (NGC 6205 or “The Great Hercules Cluster”), a globular star cluster located about 25,000 light-years from Earth in the constellation of Hercules.
This historic signal was the Arecibo Message, humanity’s first attempt at Messaging Extraterrestrial Intelligence (METI). Almost fifty years later, the Message remains a focal point in the Search for Extraterrestrial Intelligence (SETI), the ethics of messaging, and why we haven’t heard from any extraterrestrial civilization (the Fermi Paradox). What’s more, a growing movement today would like to see more METI efforts mounted in the future.
The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester
On November 1st, 1961, a number of prominent scientists converged on the National Radio Astronomy Observatory in Green Bank, West Virginia, for a three-day conference. A year earlier, this facility had been the site of the first modern SETI experiment (Project Ozma), where famed astronomers Frank Drake and Carl Sagan used the Green Bank telescope (aka. “Big Ear”) to monitor two nearby Sun-like stars – Epsilon Eridani and Tau Ceti.
While unsuccessful, Ozma became a focal point for scientists who were interested in this burgeoning field known as the Search for Extraterrestrial Intelligence (SETI). As a result, Drake and Sagan were motivated to hold the very first SETI conference, wherein the subject of looking for possible extraterrestrial radio signals would be discussed. In preparation for the meeting, Drake prepared the following heuristic equation:
N = R* x fp x ne x fl x fi x fc x L
This would come to be known as the “Drake Equation,” which is considered by many to be one of the most renowned equations in the history of science. On the sixtieth anniversary of its creation, John Gertz – a film producer, amateur astronomer, board-member with BreakThrough Listen, and the three-term former chairman of the board for the SETI Institute – argues in a recent paper that a factor by factor reconsideration is in order.
The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester
Is there life out there in the Universe? That is a question that has plagued humanity long before we knew just how vast the Universe was – i.e. before the advent of modern astronomy. Within the 20th century – thanks to the development of modern telescopes, radio astronomy, and space observatories – multiple efforts have been made in the hopes of finding extraterrestrial intelligence (ETI).
Leonard Nimoy with SETI astronomer Frank Drake on September 8, 1994. Seth Shostak, also from SETI, was the photographer. Image courtesy the Drake family.
Leonard Nimoy played a half-alien-half-human character — Spock — who seemingly was going to live forever. He survived having his brain removed, being bitten by a deadly alien creature and other harrowing experiences. Later, he actually did give his life to save his crew but was resurrected. And he was transported through time in the Star Trek universe to spend his life across hundreds of years. But the very human Nimoy died earlier today at age 83, leaving a legacy of not just an enduring science fiction character, but the generations of scientists and explorers he inspired.
Nimoy had been hospitalized earlier in the week and his agent confirmed his death on February 27, saying the cause was end-stage chronic obstructive pulmonary disease. Nimoy announced that he had the disease last year and attributed it to years of smoking, a habit he had quit nearly 30 years ago.
Nimoy was active on social media, and for the past couple of months, he seemed to be sending farewell messages to his fans with words of wisdom and sentiment that ended with “LLAP” — “live long and prosper” — a phrase made famous by Nimoy and his character Spock:
A life is like a garden. Perfect moments can be had, but not preserved, except in memory. LLAP
Now, following the announcement of his passing there has been an outpouring of sentiments for Nimoy and his character on social media, with expressions of how Nimoy inspired generations to look up and reach for the final frontier.
I’m a planetary scientist bc of Star Trek. I know I’m not the only one.
The Spock character was known for Vulcan logic and pointy ears, and Nimoy was a favorite with Star Trek fans of all ages. Nimoy not only appeared in the original Star Trek but he reprised his role in later Trek incarnations. He appeared in a total of eight Star Trek movies, and three different Star Trek series (original, animated and Star Trek: the Next Generation).
In addition to Star Trek, Nimoy appeared in “The Twilight Zone,” “Mission Impossible,” “THEM!” “The Brain Eaters,” “Sea Hunt,” “The Outer Limits,” “Get Smart,” “The Man From U.N.C.L.E.,” “Night Gallery,” and was host of “In Search Of.” He also wrote two autobiographies (“I Am Not Spock” and “I am Spock,”) wrote and performed on 5 albums (one was titled, “Leonard Nimoy Presents Mr. Spock’s Music from Outer Space,”) was a photographer and poet, contributed to vocal acting, and directed 6 feature films, including “Star Trek IV: the Voyage Home,” and “Three Men and a Baby.”
He is survived by his wife, Susan, as well as two children and six grandchildren from his first marriage to Sandra Zober.
Spock has now reached the final frontier. Tonight we’ll toast his legacy of the “good of the many.”
This interview with Frank Drake — sometimes called the Father of the Search for Extraterrestrial Intelligence – was recorded in 2012 but not released until now to celebrate the beginning of the 30th year of the SETI Institute. As interviewer Andrew Fraknoi says, “I don’t think anyone had a conversation like this that was recorded with Galileo or William Herschel or Edwin Hubble, but I get to do it with Frank Drake!”
This is a great conversation that alternates between Drake’s current work with SETI and the history of his work that led to the famous Drake Equation. Fraknoi and Drake have an interesting exchange about the value of N, which is the number of civilizations in The Milky Way Galaxy whose electromagnetic emissions would be detectable.
It was recorded in June 2012 at an event called SETICon, which featured a series of talks, panels, and events featuring scientists, authors, futurists, and film-makers.
