Before we Develop Self-Replicating Machines to Explore the Universe, we Should Figure out how to Turn Them off Again

An early NASA concept of an interstellar space probe. Credit: NASA/Johns Hopkins University Applied Physics Laboratory

In 1948/49, famed computer scientist, engineer, and physicist John von Neumann introduced the world to his revolutionary idea for a species of self-replicating robots (aka. “Universal Assemblers”). In time, researchers involved in the Search for Extraterrestrial Intelligence (SETI) adopted this idea, stating that self-replicating probes would be an effective way to explore the cosmos and that an advanced species may be doing this already. Among SETI researchers, “Von Neumann probes” (as they’ve come to be known) are considered a viable indication of technologically advanced species (technosignature).

Given the rate of progress with robotics, it’s likely just a matter of time before humanity can deploy Von Neumann probes, and the range of applications is endless. But what about the safety implications? In a recent study by Carleton University Professor Alex Ellery explores the potential harm that Von Neumann Probes could have. In particular, Ellery considers the prospect of runaway population growth (aka. the “grey goo problem”) and how a series of biologically-inspired controls that impose a cap on their replication cycles would prevent that.

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Snooping on Alien Messages Passing Through the Solar System

Researchers at Penn State University have studied a new technique that could use a star’s ability to focus and magnify communications which could be passing through our own solar system, and has been accepted for publication in The Astronomical Journal and was part of a graduate course at Penn State covering the Search for Extraterrestrial Intelligence (SETI. The study describes our Sun as potentially acting as a kind of node as part of an interstellar communication network involving probes or relays near our Sun, acting like cellular telephone towers in space.

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Why Would an Alien Civilization Send Out Von Neumann Probes? Lots of Reasons, says a new Study

Artist's concept of the New Horizons spacecraft encountering a Kuiper Belt object, part of an extended mission after the spacecraft’s July 2015 Pluto flyby. Credits: NASA/JHUAPL/SwRI

In 1948-49, mathematician, physicist, computer scientist, and engineer John von Neumann introduced the world to his idea of “Universal Assemblers,” a species of self-replicating robots. Von Neumann’s ideas and notes were later compiled in a book titled “Theory of self-reproducing automata,” published in 1966 (after his death). In time, this theory would have implications for the Search for Extraterrestrial Intelligence (SETI), with theorists stating that advanced intelligence must have deployed such probes already.

The reasons and technical challenges of taking the self-replicating probe route are explored in a recent paper by Gregory L. Matloff, an associate professor at the New York City College of Technology (NYCCT). In addition to exploring why an advanced species would opt to explore the galaxy using Von Neumann probes (which could include us someday), he explored possible methods for interstellar travel, strategies for exploration, and where these probes might be found.

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What is the Kardashev Scale?

Nikolai Kardashev (1932-2019), Credit: IAU

Are we alone in the Universe? Could there be countless sentient life forms out there just waiting to be found? Will we meet them someday and be able to exchange knowledge? Will we even recognize them as intelligent life forms if/when we meet them, and them us? When it comes to astrobiology, the search for life in the Universe, we don’t know what to expect. Hence why all the speculation and theoretical studies into these questions are so rich and varied!

One such study was conducted by famed Soviet and Russian astrophysicist and radio astronomer Nikolai Kardashev (1932 – 2019). While considering an important question related to the Search for Extraterrestrial Intelligence (SETI) in 1964, Kardashev proposed a classification scheme for ranking a civilization’s development. This would come to be known as the Kardashev Scale, which remains one of the most influential concepts in SETI to this day.

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What is the Arecibo Message?

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.

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If Alien Probes are Already in the Solar System, Maybe we Could Detect Them Calling Home

Artist's impression of the Milky Way Galaxy. Credit: ESO

It’s been seventy years since physicist Enrico Fermi asked his famous question: “Where is everybody?” And yet, the tyranny of the Fermi Paradox is still with us and will continue to be until definitive evidence of Extraterrestrial Intelligence (ETI) is found. In the meantime, scientists are forced to speculate as to why we haven’t found any yet and (more importantly) what we should be looking for. By focusing our search efforts, it is hoped that we may finally determine that we are not alone in the Universe.

In a recent study, two researchers from the University of Liège and the Massachusetts Institute of Technology (MIT) recommended that we look for evidence of transmissions from our Solar System. Based on the theory that ETIs exist and have already established a communications network in our galaxy, the team identified Wolf 359 as the best place to look for possible interstellar communications from an alien probe.

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If Aliens Are Out There, We’ll Meet Them in a Few Hundred Million Years

An artist's conception of how common exoplanets are throughout the Milky Way Galaxy. Image Credit: Wikipedia

Seventy years ago, Italian-American nuclear physicist Enrico Fermi asked his colleagues a question during a lunchtime conversation. If life is common in our Universe, why can’t we see any evidence of its activity out there (aka. “where is everybody?”) Seventy years later, this question has launched just as many proposed resolutions as to how extraterrestrial intelligence (ETIs) could be common, yet go unnoticed by our instruments.

Some possibilities that have been considered are that humanity might be alone in the Universe, early to the party, or is not in a position to notice any yet. But in a recent study, Robin Hanson (creator of the Great Filter) and an interdisciplinary team offer a new model for determining when the aliens will get here. According to their study, humanity is early to the Universe and will meet others in 200 million to 2 billion years from now.

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Oumuamua Isn’t an Alien Probe, Because Aliens can Learn Everything They Need About us With Telescopes

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

In the Fall of 2017, the first known interstellar object passed through the Solar System, triggering a revolution in astronomy. Because of the amonolous nature of the object, astronomers from all over the world were at a loss to explain what it was. Neither comet, nor asteroid, nor any other conventional object appeared to fit the bill, leading to all kinds of “exotic” explanations.

A particularly exotic explanation was offered by Harvard Professor Avi Loeb and his former postdoc (Dr. Shmuel Bialy), who hypothesized that ‘Oumuamua could have been an extraterrestrial lightsail. Whereas most rebuttal papers questioned the evidence presented, a new study by astrophysicist and UCLA emeritus professor Ben Zuckerman questioned something else: why would an extraterrestrial civilization want to send a probe our way?

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According to the Math, it’s Highly Unlikely That an Intelligent Civilization is Located at Alpha Centauri

The Parkes radio telescope at Parkes Observatory in New South Wales, Australia. Astronomers using the telescope detected what appeared to be a radio signal coming from the direction of Proxima Centauri in April and May 2019. Image via Daniel John Reardon/ Wikimedia Commons.

In December of 2020, the world got a bit of a pre-holiday surprise when it was announced that astronomers at the Parkes radio telescope in Australia had detected a “tantalizing” signal coming from Proxima Centauri (the red dwarf companion of the Alpha Centauri system). Afterward, researchers at Breakthrough Listen consulted the data on the signal – Breakthrough Listen Candidate 1 (BLC1) – and noted the same curious features.

However, the scientific community has since announced that the signal is unlikely to be anything other than the result of natural phenomena. This was also the conclusion reached by Amir Siraj and Prof. Abraham Loeb of Harvard University after they conducted a probability assessment on BLC1. Like the vast majority of candidate radio signals discovered to date, this one appears to be just the forces of nature saying hello.

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Beyond “Fermi’s Paradox” XVI: What is the “Dark Forest” Hypothesis?

The Full Moon at 10:30 p.m. last night (Aug. 30). Even at 25 altitude, it glowed a deep, dark orange due to heavy smoke from western forest fires. Credit: Bob King

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that Earth hasn’t been visited by aliens because interstellar travel is not very practical!

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?

This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Dark Forest Hypothesis, where extraterrestrial civilizations are deliberately avoiding contact.

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