Extraterrestrial Civilizations Archives

January 11, 2025January 11, 2025 by Mark Thompson

Could We Detect Advanced Civilisations by their Industrial Pollution? Probably Not.

The MAIA satellite mission, a partnership between NASA and Italy's Agenzia Spaziale Italiana (ASI), will investigate the effects of particulate matter air pollution on human health. Suicup/Wikimedia Commons, CC BY-SA 3.0

The hunt for aliens goes hand in hand with the hunt for habitable planets. Astronomers are on the hunt for exoplanets with atmospheric chemicals that could be a sign of an advanced civilisation. These chemicals, known as technosignatures are found on Earth and are the result of burning fossil fuels. A team of researchers have been exploring Polycyclic Aromatic Hydrocarbons and whether they could detect them.

December 17, 2024December 17, 2024 by Paul M. Sutter

What is the Zoo Hypothesis?

It seems that we are completely alone in the universe. But simple reasoning suggests that there should be an abundance of alien civilizations. Maybe they’re all out there, but they are keeping their distance. Welcome to the zoo (hypothesis).

December 16, 2024December 16, 2024 by Matt Williams

A New Study Suggests How we Could Find Advanced Civilizations that Ran Out of Fusion Fuel

This view of Earth’s horizon was taken by an Expedition 7 crewmember onboard the International Space Station, using a wide-angle lens while the Station was over the Pacific Ocean. A new study suggests that Earth's water didn't all come from comets, but likely also came from water-rich planetesimals. Credit: NASA

When it comes to our modern society and the many crises we face, there is little doubt that fusion power is the way of the future. The technology not only offers abundant power that could solve the energy crisis, it does so in a clean and sustainable way. At least as long as our supplies of deuterium (H₂) and helium-3 hold up. In a recent study, a team of researchers considered how evidence of deuterium-deuterium (DD) fusion could be used as a potential technosignature in the Search for Extraterrestrial Intelligence (SETI).

December 6, 2024December 6, 2024 by Evan Gough

Advanced Civilizations Could be Indistinguishable from Nature

The Search for Extraterrestrial Intelligence. Image Credit: SETI

Sometimes in science you have to step back and take another look at underlying assumptions. Sometimes its necessary when progress stalls. One of the foundational questions of our day concerns the Fermi Paradox, the contradiction between what seems to be a high probability of extraterrestrial life and the total lack of evidence that it exists.

What assumptions underlie the paradox?

November 13, 2024December 12, 2024 by Matt Williams

New Study Examines How Extraterrestrial Civilizations Could Become “Stellivores.”

Artist's impression of accretion in a binary system. Credit: ESO/L. Calçada

One of the most challenging aspects of astrobiology and the Search for Extraterrestrial Intelligence (SETI) is anticipating what life and extraterrestrial civilizations will look like. Invariably, we have only one example of a planet that supports life (Earth) and one example of a technologically advanced civilization (humanity) upon which to base our theories. As for more advanced civilizations, which statistically seems more likely, scientists are limited to projections of our own development. However, these same projections offer constraints on what SETI researchers should search for and provide hints about our future development.

In a series of papers led by the Blue Marble Space Institute of Science (BMSIS), a team of researchers examines what Earth’s level of technological development (aka. “technosphere”) will look like in the future. In the most recent installment, they offer a reinterpretation of the Kardashev Scale, which suggests that civilizations expand to harness greater levels of energy (planet, host star, and galaxy). Instead, they suggest that the Kardashev Scale establishes upper limits on the amount of stellar energy a civilization can harness (a “luminosity limit”) and that civilizations might circumvent this by harnessing stellar mass directly.

August 7, 2024August 9, 2024 by Matt Williams

New Study Suggests that Our Galaxy is Crowded or Empty. Both are Equally Terrifying!

Gaia's all-sky view of our Milky Way Galaxy and neighbouring galaxies, based on measurements of nearly 1.7 billion stars. The map shows the total brightness and colour of stars observed by the ESA satellite in each portion of the sky between July 2014 and May 2016. Brighter regions indicate denser concentrations of especially bright stars, while darker regions correspond to patches of the sky where fewer bright stars are observed. The colour representation is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky. The bright horizontal structure that dominates the image is the Galactic plane, the flattened disc that hosts most of the stars in our home Galaxy. In the middle of the image, the Galactic centre appears vivid and teeming with stars. More information on: http://sci.esa.int/gaia/60169-gaia-s-sky-in-colour/

Is there intelligent life in the Universe? And if so, just how common is it? Or perhaps the question should be, what are the odds that those engaged in the Search for Extraterrestrial Intelligence (SETI) will encounter it someday? For decades, scientists have hotly debated this topic, and no shortage of ink has been spilled on the subject. From the many papers and studies that have been written on the subject, two main camps have emerged: those who believe life is common in our galaxy (aka. SETI Optimists) and those who maintain that extraterrestrial intelligence is either rare or non-existent (SETI Pessimists).

In a recent paper, David Kipping (Prof. “Cool Worlds” himself) and Geraint Lewis examined this debate more closely and offered a fresh take based on a form of probability analysis known as Jayne’s Experiment. By applying this method to astrobiology and the Drake Equation, they concluded that the existence of intelligent life in our galaxy may be an “all or nothing” proposition. To quote the late and great scientist and science fiction author Arthur C. Clarke: “Two possibilities exist: either we are alone in the Universe, or we are not. Both are equally terrifying.”

June 14, 2024June 14, 2024 by Evan Gough

Warp Drives Could Generate Gravitational Waves

This artist's illustration shows a spacecraft using an Alcubierre Warp Drive to warp space and 'travel' faster than light. Image Credit: NASA

Will future humans use warp drives to explore the cosmos? We’re in no position to eliminate the possibility. But if our distant descendants ever do, it won’t involve dilithium crystals, and Scottish accents will have evaporated into history by then.

February 27, 2024February 27, 2024 by Evan Gough

Some Intelligent Civilizations Will Be Trapped on their Worlds

With thousands of exoplanets discovered so far, astronomers are learning how different planets can be. What if intelligent alien civilizations arise on extremely different habitable worlds? Some civilizations could develop space exploration technologies, but others would be trapped underwater, under ice, or in enormous gravity wells. How could they escape? Image Credit: DALL-E

Evolution has produced a wondrously diverse variety of lifeforms here on Earth. It just so happens that talking primates with opposable thumbs rose to the top and are building a spacefaring civilization. And we’re land-dwellers. But what about other planets? If the dominant species on an ocean world builds a technological civilization of some sort, would they be able to escape their ocean home and explore space?

January 12, 2023January 12, 2023 by Evan Gough

Game of Probes: The First Probe Sent to Another Civilization Won’t Be the First to Arrive

An artist's concept of Voyager 1's view of the Solar System. Voyager 1 is one of our first interstellar probes, though it's an inadvertent one. It has no particular destination. Credit: NASA, ESA, and J. Zachary and S. Redfield (Wesleyan University); Artist's Illustration Credit: NASA, ESA, and G. Bacon (STScI).

If we ever detect an Extraterrestrial Civilization (ETC) and start communicating with them, the messages could take years, decades, or even centuries to travel back and forth. We face a challenging 49-minute long delay just communicating with the Juno spacecraft orbiting Jupiter, and that’s well within our Solar System. Communicating with an ETC that’s hundreds of light-years away or even further is a daunting task.

It’s even worse if we’re sending probes.