Extraterrestrial Archives

May 31, 2022May 31, 2022 by Evan Gough

Civilizations Don’t Even Need Space Ships to Migrate From Star System to Star System

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Image Credit: ESO/M. Kornmesser/S. Guisard

In about 5 billion years, the Sun will leave the main sequence and become a red giant. It’ll expand and transform into a glowering, malevolent ball and consume and destroy Mercury, Venus, Earth, and probably Mars. Can humanity survive the Sun’s red giant phase? Extraterrestrial Civilizations (ETCs) may have already faced this existential threat.

Could they have survived it by migrating to another star system without the use of spaceships?

May 18, 2022May 18, 2022 by Evan Gough

Maybe We Don’t Hear From Aliens Because They Choose To Go Silent

Artist impression of an alien civilization. Image credit: CfA

How will humanity meet its end?

That’s only a depressing question if you think that humanity will go on forever. Alas, nothing lasts forever, and if something could last forever, it probably wouldn’t be our struggling primate species.

But we’ll likely be around for a while yet, pondering things as we do. One of the things we love to ponder is: why don’t we hear from any other alien civilizations?

March 12, 2022December 24, 2023 by Matt Williams

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.

January 10, 2022January 10, 2022 by Matt Williams

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.

November 22, 2021November 24, 2021 by Matt Williams

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.

November 13, 2021November 16, 2021 by Matt Williams

Not Saying it was Aliens, but ‘Oumuamua Probably Wasn’t a Nitrogen Iceberg…

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

On October 19^th, 2017, astronomers made the first-ever detection of an interstellar object (ISO) passing through our Solar System. Designated 1I/2017 U1′ Oumuamua, this object confounded astronomers who could not determine if it was an interstellar comet or an asteroid. After four years and many theories (including the controversial “ET solar sail” hypothesis), the astronomical community appeared to land on an explanation that satisfied all the observations.

The “nitrogen iceberg” theory stated that ‘Oumuamua was likely debris from a Pluto-like planet in another solar system. In their latest study, titled “The Mass Budget Necessary to Explain ‘Oumuamua as a Nitrogen Iceberg,” Amir Siraj and Prof. Avi Loeb (who proposed the ET solar sail hypothesis) offered an official counter-argument to this theory. According to their new paper, there is an extreme shortage of exo-Plutos in the galaxy to explain the detection of a nitrogen iceberg.

November 4, 2021 by Andy Tomaswick

NASA is Getting Serious About the Search for Life in the Universe

Frameworks are a valuable tool in science. They give context to sometimes abstract concepts such as “how powerful can an alien civilization be” (Kardashev scale) or “how developed is this technology?” (Technology Readiness Levels). Now, NASA has developed a new scale to help give context to what some consider one of the agency’s most critical missions – the search for extraterrestrial life.

September 17, 2021September 17, 2021 by Matt Williams

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.

August 10, 2021August 11, 2021 by Matt Williams

We’ll Have to Wait About 3,000 Years for a Reply From Intelligent Civilizations

Artist’s impression of CSIRO’s Australian SKA Pathfinder (ASKAP) radio telescope finding a fast radio burst and determining its precise location. The KECK, VLT and Gemini South optical telescopes joined ASKAP with follow-up observations to image the host galaxy. Credit: CSIRO/Dr Andrew Howells

As a field, the Search for Extraterrestrial Intelligence suffers from some rather significant constraints. Aside from the uncertainty involved (e.g., is there life beyond Earth we can actually communicate with?), there are the limitations imposed by technology and the very nature of space and time. For instance, scientists are forced to contend with the possibility that by the time a message is received by an intelligent species, the civilization that sent it will be long dead.

Harvard astronomers Amir Siraj and Abraham Loeb tackle this very question in a new study that recently appeared online. Taking their cue from the Copernican Principle, which states that humanity and Earth are representative of the norm (and not an outlier), they calculated that if any transmissions from Earth were heard by an extraterrestrial technological civilization (ETC), it would take about 3000 years to get a reply.

July 28, 2021July 29, 2021 by Matt Williams

A New Plan to Search for Extraterrestrial Artifacts at Earth and Across the Solar System

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

On October 19th, 2017, astronomers made the first-ever detection of an interstellar object (ISO) in our Solar System. This body, named 1I/2017 U1 (‘Oumuamua), was spotted shortly after it flew by Earth on its way to the outer Solar System. Years later, astronomers are still hypothesizing what this object could have been (an interstellar “dust bunny,” hydrogen iceberg, nitrogen icebergs), with Harvard Prof. Abraham Loeb going as far as to suggest that it might have been an extraterrestrial solar sail.

Roughly three years later, interest in extraterrestrial visitors has not subsided, in part because of the release of the Pentagon report on the existence of “Unidentified Aerial Phenomena.” This prompted Loeb and several of his fellow scientists to form the Galileo Project, a multi-national, multi-institutional research team dedicated to bringing the search for Extraterrestrial Technological Civilizations (ETC) into the mainstream.