Buzz
In 1950, Nobel-winning physicist Enrico Fermi posed a famous question to his colleagues during lunch: "Where is everybody?" This question later became known as the Fermi Paradox. He was curious why, despite the abundance of habitable planets in the universe, we haven’t encountered any extraterrestrial life.
There are numerous theories explaining why we haven’t made contact with alien civilizations (at least, not that we know of). However, we may have simply made a cosmic error in our assumptions. We initially presumed alien life would resemble us. If that assumption is incorrect, all of our efforts to locate alien life become meaningless. Now, we're revising that assumption and expanding our strategies to engage with life forms that might be vastly different from us.
10. The Decline of Radio Wave SETI
For more than 50 years, SETI has been listening for signals from the cosmos. In 1974, astronomer Frank Drake transmitted the first radio message, the “Arecibo Message,” aimed at potential extraterrestrial civilizations. To date, we’ve yet to receive a response. Although NASA seems focused on the search for alien life, Drake has voiced concerns about a lack of funding. In fact, there are fears that NASA may dismantle the Arecibo and Green Bank telescopes, which would essentially end SETI’s radio efforts. Meanwhile, China has developed an advanced radio telescope, though Drake is uncertain whether it will work effectively.
On the other hand, optical SETI, which looks for laser pulses, is thriving thanks to private donations. Unlike radio signals, optical signals rely on aliens directing their beams directly at Earth. “The signals are so powerful that even small telescopes can detect them,” said Drake. “Smaller telescopes can provide more observing time, which is beneficial because we need to scan a large number of stars for any chance of success.” Drake remains hopeful that if aliens are targeting us, they might be acting out of goodwill.
However, not everyone shares his optimism. There’s ongoing debate among experts over whether we should be sending messages into space at all. Many scientists warn that contacting extraterrestrials prematurely could pose a danger to our safety, given our current technological limitations. John Elliott of SETI notes that some within the SETI community have already begun transmitting messages despite the risks. For the record, Drake is opposed to actively sending signals to aliens, a practice known as active SETI. He prefers the approach of simply listening for extraterrestrial signals.
9. Communicating with Aliens 101
John Elliott from the UK SETI Research Network argues that we should move beyond simply searching for alien signals and focus on distinguishing between a potential alien language and random noises. After analyzing over 60 human languages, he identified a common signature in the structure and rhythm of each language. For example, every language contains content words and short function words (such as 'if' and 'but') that connect phrases. Regardless of the language, humans typically use no more than nine content words in a single phrase.
Some animal species, like dolphins, share a similar language signature. While we cannot yet speak dolphin language, we are able to recognize around 140 distinct sounds in their vocalizations. Dolphins always introduce themselves with a personal name or call sign when communicating, and they limit their phrases to no more than five content words. Elliott believes this pattern aligns with their smaller brain size and information-processing abilities.
Elliott has created a set of small computer programs, called the Natural Language Learner, to analyze alien signals for signs of language complexity and internal structure. However, he is likely not yet able to decode the actual content of those signals.
Establishing communication with intelligent animals on Earth might be the first step toward learning how to communicate with extraterrestrials. We have taught dolphins hundreds of human words, the difference between questions and statements, and concepts like 'none' along with other forms of syntax. As an early effort to create two-way communication between humans and animals, biologist Denise Herzing developed a game where dolphins and humans could learn to communicate using a basic shared language. Female dolphins were more engaged in communication than males and even invited dolphins from other species to join the interaction.
We’ve also discovered that wild Campbell’s monkeys use suffixes to modify certain sounds to warn others of various dangers. For instance, the call “krak” signals the presence of a leopard, their natural predator. However, “krak-oo” serves as a more general alert to warn about potential threats like falling branches or territorial intruders. Diana monkeys are also capable of understanding these calls from Campbell’s monkeys.
In another study, adult chimpanzees from the Netherlands adjusted their call for apples to align with the local chimp language after relocating to a zoo in Scotland and befriending the resident chimpanzees. The question remains whether this shift represents a change in accent or the development of a second language, suggesting potential bilingualism.
8. Party Like It’s AD 1015
The success of SETI hinges on the assumption that intelligent extraterrestrials are using technology to send signals. While technologically advanced beings must be intelligent, intelligence doesn’t necessarily require the use of technology. Consider dolphin intelligence: although dolphins lack the physical limbs to create and use complex tools, their intelligence is undeniable. Could other forms of alien life be similarly non-technological yet still highly intelligent? Does intelligence lie in the use of technology or the ability to communicate and socialize?
Are we being too arrogant in assuming that we are more intelligent than creatures like dolphins? As Carl Sagan pointed out, “While some dolphins are reported to have learned English—up to 50 words used in correct context—no human being has been reported to have learned dolphinese.” They also don’t use technology to harm one another.
In preparation for potential alien contact, Laurance Doyle of SETI plans to explore the concept of communication between trees. Trees use chemicals to warn one another about pests and other threats. “Who knows? Brains might not be necessary,” he remarked.
In either of these scenarios, we would need to travel to where the aliens are located, rather than waiting for them to reach out to us.
However, there’s an even more basic reason we might not hear from aliens in our lifetime, even if they are just like us. When we use telescopes to observe outer space, we’re not seeing the present, but rather the past. “We…see back in time because light takes time to get from there to here,” explained Jonathan Gardner of NASA. “So, as we look farther away, it takes longer for the light to travel from where it was emitted to here, and we can literally see into the past. And if we look far enough, we’re seeing the universe when it was much younger, before the light from those galaxies was emitted.”
If aliens are observing us through their telescopes, they too would be seeing us in the past. For instance, aliens living 1,000 light-years away would be viewing us in AD 1015. Since radio amplifiers were only invented in 1907, it may take another 900 years for aliens to detect radio signals from Earth (assuming they’re even using that technology).
7. The Social Scientists Weigh In
Typically, we rely on the hard sciences—astronomy, computer science, engineering, physics—to lead the way in communicating with extraterrestrial life. However, Doug Vakoch, Director of Interstellar Communication at the SETI Institute, has edited a free book titled Archaeology, Anthropology, and Interstellar Communication that approaches this issue from the viewpoint of social scientists.
Every day, archaeologists and anthropologists work to uncover the mysteries of ancient civilizations from just a few scattered clues. While we can never be completely certain of the accuracy of their conclusions, we often interpret past cultures through the lens of our own beliefs. At least we share a common human heritage. But how can we begin to decipher messages from an alien civilization—one that may possess entirely different sensory organs and interpret messages in ways beyond our understanding?
We tend to assume that alien civilizations will be unified under a single culture. However, this could be one of the few similarities between us and them. “We must face the reality that we could be encountering a world fragmented into different cultural frameworks, much like our own, made up of beings who may not all respond to contact with us in the same way,” says John Traphagan in the book. “Technological progress on Earth hasn’t always been linked to greater political or social unity (think of the World Wars). It seems reasonable to believe that we’ll be dealing with beings shaped by shared memories who will not only share but also debate and challenge ideas formed within the contexts of those shared experiences about how to handle contact with humans.”
They’re essentially saying that, at this point, we have little hope of decoding an alien communication or of responding in a meaningful way.
6. Heat Signatures
By analyzing data from 100,000 galaxies observed by NASA’s Wide-field Infrared Survey Explorer (WISE), scientists searched for heat signatures that could point to the existence of advanced extraterrestrial civilizations. 'Whether an advanced spacefaring civilization uses the abundant energy from its galaxy’s stars to fuel computers, space travel, communication, or some technology we can’t yet conceive of, basic thermodynamics dictates that this energy must radiate as heat in the mid-infrared spectrum,' explained researcher Jason Wright from Pennsylvania State University. 'This same principle is why your computer emits heat when it’s turned on.'
Unfortunately, scientists didn’t find any definitive proof of an advanced civilization. This was surprising, given that the galaxies have been around for billions of years. By now, they should have been populated by aliens. The researchers concluded that either aliens don’t exist in those galaxies or they’re simply not advanced enough to emit a detectable heat signature.
Nevertheless, the team identified 50 galaxies emitting unusually high levels of mid-infrared radiation. Additional studies are needed to determine whether this heat originates from natural sources or if it could be an alien heat signature.
5. Frugal Aliens
Although we don’t say it outright, our assumptions about extraterrestrial life often rely on the belief that they possess infinite resources to communicate. We’ve acted as though aliens should devote every moment to sending us signals. If they’re not, then they simply can’t exist.
This reflects the height of human arrogance. If NASA needs to reduce its budget to conserve resources, why couldn’t aliens face the same issue? A 2010 study by Microwave Sciences suggested that aliens might transmit signals at higher frequencies than those monitored by SETI, in order to save money. SETI researchers focus on the 1.42–1.72 gigahertz range because certain interstellar clouds emit radiation in this band. However, the scientists at Microwave Sciences believe that aliens would likely use frequencies closer to 10 gigahertz, as it would be cheaper and easier to produce a powerful beam at that frequency.
Using this strategy, aliens would likely send signals only a few times each year. 'Astronomers have detected some unexplained signals that lasted only a few seconds, and then they vanished,' says Benford. 'Some of these could be extraterrestrial beacons, but there wasn't enough observation time to catch any repeated signals.'
This might explain the 72-second WOW signal detected by a SETI researcher in 1977. Some scientists think it could have been an alien transmission. It's named the WOW signal because the researcher wrote 'Wow' in the margin of his notes. The signal remains a mystery—its origin and nature are unknown, and it has never been observed again.
4. Ether-Based DNA
We've long believed that water is essential for life, but now scientists are exploring whether other liquids, like methane found on Saturn's moon Titan, could also support life. For life to form in such an environment, different molecules called ethers would be needed to create the necessary chemical reactions. These ethers, when combined, could form complex polyethers, potentially leading to life. DNA and RNA, however, can't dissolve in hydrocarbons and would become clogged up instead.
Like water, hydrocarbons can exist as liquids, solids, or gases. However, solids and gases won't allow biomolecules to interact in a way that could support life, so what we really need is liquid hydrocarbons—a kind of oily Earth. Octane, which remains liquid over the broadest temperature range, offers the most favorable conditions for life. Propane and methane work in more limited ranges, but Titan's extreme cold makes it unlikely to support life.
"Within our own solar system, we do not have a planet that is large enough, close enough to the Sun, and with the right temperature to support warm hydrocarbon oceans on its surface," said Steven Benner, a researcher at the Foundation for Applied Molecular Evolution. However, with the increasing discovery of new solar systems, it's possible that we'll soon find a planet or moon with the right conditions to support life in a hydrocarbon ocean.
3. The Best Place To Look For Life
While much of our focus has been on Mars in the search for alien life, there may be more promising prospects beyond, in the icy moons of the outer solar system—such as Enceladus, Europa, and Ganymede. These moons, with their hidden oceans, could be more likely to support life. Despite the ongoing exploration of Mars by five orbiters and two rovers, moons like Europa, Ganymede, Enceladus, and Titan remain unexplored in terms of life detection. As Corey Powell from *Discover* magazine points out, we might have been searching in the wrong places all along.
One of the main reasons the outer solar system has been neglected is the significant time and cost involved in reaching those distant moons. While a journey to Mars takes about eight months, traveling to Jupiter and Saturn can take six to seven years. Despite this, we've already sent the Cassini spacecraft to Saturn and are preparing the Europa Clipper for a potential 2022 launch. Additionally, the Hubble Space Telescope and the Galileo probe have already provided valuable data from Ganymede and Enceladus.
Currently, Enceladus appears to be the most promising place to search for alien life. Beneath its icy surface lies liquid water, and researchers have found signs of active hydrothermal vents on the moon’s seafloor. Heat and water are crucial for life, and Enceladus’s subsurface oceans appear to be in contact with the moon’s mantle, allowing the water to mix with rich minerals like sulfur, potentially creating conditions conducive to life. The water on Enceladus is highly alkaline, with a pH of 11 or 12, similar to environments on Earth where life has been found.
2. The Nanosensor
When searching for life on other planets, the typical approach is to look for biochemical markers. As mentioned earlier, scientists have detected biosignatures that suggest life on planets and moons that appear lifeless. This means our current methods of detection can easily result in false positives.
MIT scientists Sara Seager and William Bain suggest that we broaden our search for signs of alien life beyond the familiar biosignatures of methane and oxygen. Seager emphasized, 'We know there will not be huge numbers of accessible planets. We want to ensure we don't overlook any potential biosignatures by thinking outside the box.' While oxygen is an excellent biosignature for Earth, Seager asks, 'What are the odds it would be found on an exoplanet?'
Seager and Bain also point out that alien life might be vastly different from what we expect, citing the surprising variety of exoplanets we've discovered. 'An astonishing discovery is that the most common type of planet in our galaxy falls between the size of Earth and Neptune,' they wrote. 'This new class of planets is neither terrestrial nor giant, and there is no clear theory explaining how they form.'
To overcome some of the challenges in detecting alien life, scientists from Belgium and Switzerland have developed a device that identifies life without relying on biosignatures. The nanomotion detector uses a cantilever (a beam fixed at one end) to scan surfaces for tiny fluctuations in the metabolic activity or movement of cells. They successfully tested it on bacteria, human, mouse, plant cells, and yeast. After killing the cells, they retested, proving the device could differentiate between life and background noise. The device also performed well with soil and water samples containing microorganisms. Each test takes around 10 minutes.
Though further testing is required, the nanomotion detector holds potential as a breakthrough tool for detecting alien life. It's compact, fast, simple, and doesn't rely on biochemical data. When combined with biochemical sensors, it could be an especially powerful tool for searching for life on moons like those of Saturn.
1. Contact Scenarios
While it may seem unlikely that we'll meet intelligent aliens face-to-face anytime soon, it's still possible that they reside underground on one of the planets or moons in our solar system, or perhaps in the asteroid belt.
In 1950, the US military outlined a strategy known as 'Seven Steps to Contact' to manage a potential first encounter with intelligent extraterrestrials. The plan began with monitoring them from afar, collecting as much information as possible. The next step involved secretly visiting to evaluate their technology, including weapons and vehicles. If our technology proved more advanced, we would approach their planet to gauge their level of hostility. If they appeared non-threatening, we would briefly land in isolated, uninhabited areas to collect samples of plant and animal life. The military also considered abducting some aliens for study without causing harm.
The following steps would involve cautiously making our presence known to the aliens, staying out of their reach while allowing as many of them as possible to observe our spacecraft. The goal would be to appear friendly and non-threatening. The final step, if deemed safe, would be to land and attempt to make direct contact with them.
Although this procedure has remained relatively unchanged, the possibility of its application is becoming more real. What happens if we encounter a species with far superior intelligence is uncertain, but we would have to hope they are peaceful. If not, we might not stand much of a chance.
