Could invisible aliens really exist among us? An astrobiologist explains
The intelligent life we are searching for doesn't have to be humanoid.
Life is pretty easy to recognise. It moves, it grows, it eats, it excretes, it reproduces.
Simple. In biology, researchers often use the acronym “MRSGREN" to describe it. It stands for movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.
But Helen Sharman, Britain's first astronaut and a chemist at Imperial College London, recently said that alien lifeforms that are impossible to spot may be living among us. How could that be possible?
While life may be easy to recognise, it's actually notoriously difficult to define and has had scientists and philosophers in debate for centuries – if not millennia. For example, a 3D printer can reproduce itself, but we wouldn't call it alive. On the other hand, a mule is famously sterile, but we would never say it doesn't live.
As nobody can agree, there are more than 100 definitions of what life is. An alternative (but imperfect) approach is describing life as “a self-sustaining chemical system capable of Darwinian evolution", which works for many cases we want to describe.
The lack of definition is a huge problem when it comes to searching for life in space. Not being able to define life other than “we'll know it when we see it" means we are truly limiting ourselves to geocentric, possibly even anthropocentric, ideas of what life looks like. When we think about aliens, we often picture a humanoid creature. But the intelligent life we are searching for doesn't have to be humanoid.
Life, but not as we know it
Sharman says she believes aliens exist and "there's no two ways about it". Furthermore, she wonders: "Will they be like you and me, made up of carbon and nitrogen? Maybe not. It's possible they're here right now and we simply can't see them."
Such life would exist in a "shadow biosphere". By that, I don't mean a ghost realm, but undiscovered creatures probably with a different biochemistry. This means we can't study or even notice them because they are outside of our comprehension. Assuming it exists, such a shadow biosphere would probably be microscopic.
So why haven't we found it? We have limited ways of studying the microscopic world as only a small percentage of microbes can be cultured in a lab. This may mean that there could indeed be many lifeforms we haven't yet spotted. We do now have the ability to sequence the DNA of unculturable strains of microbes, but this can only detect life as we know it – that contain DNA.
If we find such a biosphere, however, it is unclear whether we should call it alien. That depends on whether we mean "of extraterrestrial origin" or simply "unfamiliar".
A popular suggestion for an alternative biochemistry is one based on silicon rather than carbon. It makes sense, even from a geocentric point of view. Around 90% of the Earth is made up of silicon, iron, magnesium and oxygen, which means there's lots to go around for building potential life.
Silicon is similar to carbon, it has four electrons available for creating bonds with other atoms. But silicon is heavier, with 14 protons (protons make up the atomic nucleus with neutrons) compared to the six in the carbon nucleus. While carbon can create strong double and triple bonds to form long chains useful for many functions, such as building cell walls, it is much harder for silicon. It struggles to create strong bonds, so long-chain molecules are much less stable.
What's more, common silicon compounds, such as silicon dioxide (or silica), are generally solid at terrestrial temperatures and insoluble in water. Compare this to highly soluble carbon dioxide, for example, and we see that carbon is more flexible and provides many more molecular possibilities.
Life on Earth is fundamentally different from the bulk composition of the Earth. Another argument against a silicon-based shadow biosphere is that too much silicon is locked up in rocks. In fact, the chemical composition of life on Earth has an approximate correlation with the chemical composition of the sun, with 98% of atoms in biology consisting of hydrogen, oxygen and carbon. So if there were viable silicon lifeforms here, they may have evolved elsewhere.
That said, there are arguments in favour of silicon-based life on Earth. Nature is adaptable. A few years ago, scientists at Caltech managed to breed a bacterial protein that created bonds with silicon – essentially bringing silicon to life. So even though silicon is inflexible compared with carbon, it could perhaps find ways to assemble into living organisms, potentially including carbon.
And when it comes to other places in space, such as Saturn's moon Titan or planets orbiting other stars, we certainly can't rule out the possibility of silicon-based life.
To find it, we have to somehow think outside of the terrestrial biology box and figure out ways of recognising lifeforms that are fundamentally different from the carbon-based form. There are plenty of experiments testing out these alternative biochemistries, such as the one from Caltech.
Regardless of the belief held by many that life exists elsewhere in the universe, we have no evidence for that. So it is important to consider all life as precious, no matter its size, quantity or location. The Earth supports the only known life in the universe. So no matter what form life elsewhere in the solar system or universe may take, we have to make sure we protect it from harmful contamination – whether it is terrestrial life or alien lifeforms.
So could aliens be among us? I don't believe that we have been visited by a life form with the technology to travel across the vast distances of space. But we do have evidence for life-forming, carbon-based molecules having arrived on Earth on meteorites, so the evidence certainly doesn't rule out the same possibility for more unfamiliar life forms.
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Scientists discover the inner workings of an effect that will lead to a new generation of devices.
- Researchers discover a method of extracting previously unavailable information from superconductors.
- The study builds on a 19th-century discovery by physicist Edward Hall.
- The research promises to lead to a new generation of semiconductor materials and devices.
Credit: Gunawan/Nature magazine
Students who think the world is just cheat less, but they need to experience justice to feel that way.
- Students in German and Turkish universities who believed the world is just cheated less than their pessimistic peers.
- The tendency to think the world is just is related to the occurence of experiences of justice.
- The findings may prove useful in helping students adjust to college life.
The world is just? That’s news to a lot of people.<p>The study is the most recent addition to a long line of work focusing on the belief in justice, our behavior, and our reactions to evidence that might suggest injustice occasionally occurs. This study focuses on a personal belief in a just world, (PBJW) rather than a general belief in a just world (GBJW). The difference between them must be highlighted.</p><p>GBJW is the stance that justice prevails all over the world and that people tend to get what they deserve. PBJW is more focused on the individual's social environment and their belief that they tend to be treated justly. While several studies show PBJW correlates with a higher sense of well-being and a variety of other positive effects, a high GBJW is associated with less life satisfaction, negative behavior, and callousness towards the suffering of <a href="https://link.springer.com/book/10.1007%2F978-1-4939-3216-0" target="_blank">others</a>. This study controlled for GBJW, and focused on PBJW as much as possible. </p><p>To assure that culture was not a factor, the study included students at universities in both Germany and Turkey. </p><p>The researchers gave students at the four participating universities a series of questionnaires that asked if they ever cheated in class, if they perceived the world to be just, if they though that justice always prevailed everywhere, their tendencies towards socially appropriate behavior, their life satisfaction, and if they felt like they were treated justly by their teachers and fellow students. </p><p>The answers were statistically analyzed for relationships. While some of the connections seem trivially true, others were surprising. <strong></strong></p><p>PBJW turned out to only be an indirect predictor of if a student was likely to cheat. Both a belief in a just world and a lower likelihood of cheating were mediated by the justice experiences of the students, with more of these positive experiences lowering the rate of cheating and improving their belief in justice. This was also associated with higher levels of life satisfaction. </p><p>These effects existed across all demographics in both countries. </p>
What does this mean? Is a belief in justice a self-fulfilling prophecy?<iframe width="730" height="430" src="https://www.youtube.com/embed/6oMv-azHNCA" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p>In a way, it seems to be. People who have reason to think the world is just to them tend to interpret events in a way to sustain that belief and behave in a just manner. In a larger sense, the take away from this study is that experiences of justice, both from peers and instructors, is vital to student's wellbeing and understanding that the rules that exist about cheating are part of a larger, legitimate, system. </p><p>The researchers, citing previous studies on the perception of justice, note that "justice experiences (1) signal that university students are esteemed members of their social group, which in turn conveys feelings of belonging and social inclusion and (2) motivate them to accept and observe university rules and norms. These cognitive processes may thus strengthen their well-being and decrease the likelihood that they cheat."</p><p>The authors also suggest that if you want people (not only students) to act justly; consider treating them with "civility, respect, and dignity."</p><p>Sometimes, all it can take to help somebody act virtuously is to treat them well. Likewise, people treated harshly can rarely find reason to play by rules that don't protect them. The findings of this study will certainly add to the literature on how we perceive justice in the world around us, but might also help us remember that there are real consequences to our actions which can be much larger than we imagine. <strong></strong></p>
This could change how researchers approach vaccine development.
- The reason children suffer less from the novel coronavirus has remained mysterious.
- Researchers identified a cytokine, IL-17A, which appears to protect children from the ravages of COVID-19.
- This cytokine response could change how researchers approach vaccine development.
A member of staff wearing personal protective equipment (PPE) takes a child's temperature at the Harris Academy's Shortland's school on June 04, 2020 in London, England.
Photo by Dan Kitwood/Getty Images<p>Experts don't want to place kids at the back of the line, regardless of how strong their immune systems appear. At least one company, Moderna, <a href="https://www.businessinsider.com/coronavirus-vaccine-for-kids-moderna-plans-pediatric-trial-2020-9" target="_blank">hopes to begin testing</a> vaccines in pediatric volunteers by year's end.</p><p>Innate immune response is especially high during childhood (compared to adaptive immunity). This makes evolutionary sense: nature wants an animal to survive until its ready to procreate. Turns out the children in the study possessed high levels of cytokines that boost their immune response. The biggest impact is made by IL-17A, which appears to protect the youngest cohort from the ravages of the coronavirus. </p><p>While both age groups produced antibodies to fight off the infamous spike protein, adults that produce neutralizing antibodies actually suffer a <em>worse</em> fate. Herold says this "over-vigorous adaptive immune response" might promote inflammation, triggering acute respiratory distress syndrome (ARDS). </p><p>This matters for vaccine development. As Herold says, </p><p style="margin-left: 20px;">"Our adult COVID-19 patients who fared poorly had high levels of neutralizing antibodies, suggesting that convalescent plasma—which is rich in neutralizing antibodies—may not help adults who have already developed signs of ARDS. By contrast, therapies that boost innate immune responses early in the course of the disease may be especially beneficial."</p><p>Herold says current vaccine trials are focused on boosting neutralizing-antibody levels. With this new information, researchers may want to work on vaccines that boost the innate immune response instead. </p><p>With <a href="https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html" target="_blank">at least 55 vaccine trials</a> underway, every piece of data matters. </p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank" rel="noopener noreferrer">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
Researchers from the University of Toronto published a new map of cancer cells' genetic defenses against treatment.