Three lines of evidence point to the idea of complex, multicellular alien life being a wild goose chase. But are we clever enough to know?
- Everyone wants to know if there is alien life in the universe, but Earth may give us clues that if it exists it may not be the civilization-building kind.
- Most of Earth's history shows life that is single-celled. That doesn't mean it was simple, though. Stunning molecular machines were being evolved by those tiny critters.
- What's in a planet's atmosphere may also determine what evolution can produce. Is there a habitable zone for complex life that's much smaller than what's allowed for microbes?
Protozoa—a term for a group of single-celled eukaryotes—and green algae in wastewater, viewed under the microscope.
Credit: sinhyu via Adobe Stock<p>Another way the story of life on Earth might not get repeated elsewhere in the cosmos relates to the composition of planetary atmospheres. Our world did not begin with its oxygen-rich air. Instead, oxygen didn't show up until almost two billion years after the planet formed and one billion years after life appeared. Earth's original atmosphere was, most likely, a mix of nitrogen and CO2. Remarkably it was life that pumped the oxygen into the air as a byproduct of a novel form of photosynthesis invented by a novel kind of single-celled organism, the nucleus-bearing eukaryotes. The appearance of oxygen in Earth's air was not just a curiosity for evolution. Life soon figured out how to use the newly abundant element and, it turns out, oxygen-based biochemistry was supercharged compared to what came before. With more energy available, evolution could build ever larger and more complex critters.</p><p>Oxygen may also be unique in allowing the kinds of metabolisms in multicellular life (especially ours) needed for making fast and fast-thinking animals. Astrobiologist <a href="http://faculty.washington.edu/dcatling/Catling2008CatalystMag.pdf" target="_blank" rel="noopener noreferrer">David Catling</a> has argued that only oxygen has the right kind of chemistry that would allow for animals to form on any world.</p><p>Atmospheres may play another role in what can and can't happen in the evolution of life. In 1959, <a href="https://astro.uchicago.edu/alumni/su-shu-huang-1949.php" target="_blank" rel="noopener noreferrer">Su-Shu Huang</a> proposed that each star would be surrounded by a "<a href="https://www.nasa.gov/ames/kepler/habitable-zones-of-different-stars" target="_blank" rel="noopener noreferrer">habitable zone</a>" of orbits where a planet would have temperatures neither too hot nor too cold to keep life from forming (i.e. liquid water could exist on the planet's surface). Since then, the habitable zone has become a staple of astrobiological studies. Astronomers now know that the outer part of the habitable zone will be dominated by worlds with lots of greenhouse gases like CO<em>2</em>. A planet in a location like Mars, for example, would require a thick CO2 blanket to keep its surface above freezing. But all that CO2 could present its own problems for life. Almost all forms of animal life on Earth, including sea creatures, die when placed in CO2-rich environments. This has led astronomer <a href="https://eschwiet.github.io/" target="_blank" rel="noopener noreferrer">Eddie Schwieterman</a> and colleagues to propose a <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ab1d52" target="_blank" rel="noopener noreferrer">habitable zone for complex life</a>: A band of orbits where planets can stay warm without requiring heavy CO2 atmospheres. According to Schwieterman, animal life of the kind we know would only be able to form in this much thinner band of orbits. </p>
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How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p>
"The Expanse" is the best vision I've ever seen of a space-faring future that may be just a few generations away.
- Want three reasons why that headline is justified? Characters and acting, universe building, and science.
- For those who don't know, "The Expanse" is a series that's run on SyFy and Amazon Prime set about 200 years in the future in a mostly settled solar system with three waring factions: Earth, Mars, and Belters.
- No other show I know of manages to use real science so adeptly in the service of its story and its grand universe building.
Credit: "The Expanse" / Syfy<p>Now, I get it if you don't agree with me. I love "Star Trek" and I thought "Battlestar Galactica" (the new one) was amazing and I do adore "The Mandalorian". They are all fun and important and worth watching and thinking about. And maybe you love them more than anything else. But when you sum up the acting, the universe building, and the use of real science where it matters, I think nothing can beat "The Expanse". And with a <a href="https://www.rottentomatoes.com/tv/the_expanse" target="_blank">Rotten Tomato</a> average rating of 93%, I'm clearly not the only one who feels this way.</p><p>Best.</p><p>Show.</p><p>Ever. </p>
Surprising as it may seem, we are all very good at denial. Negation, however, is a different phenomena.
- What makes a person espouse an ideology so intensely as to negate the reality of well-established facts? Perhaps the differences between negation and denial can help us understand.
- Negation looks to the past, while denial looks to the present and future. We negate a historical fact and we deny the reality in front of us. Negation involves a conscious choice to lie, even if it involves the suffering of millions. Denial is subtler and, surprisingly, we all do it.
- Climate change conflates both negation and denial. Hopefully, understanding why will spur more into action, as we choose to become heroes of a new anti-denialist narrative.
Trump supporters lined the street on President's Day to show support for him after his 2020 election loss to President Joe Biden.
Credit: Joe Raedle/Getty Images<p>We can thus begin to see why so many people in the US have chosen to deny the reality of the Biden-Harris election, or that masks and social distancing are essential tools to beat the pandemic. When ex-president Trump claimed that there was a plot to steal the election from him, he positioned himself as the hero-martyr, the victim of a destructive plot that was after him and, by proxy, also after everyone who supported him. He used the old trick of galvanizing a visceral group response by creating a fake reality that bundles people together in a single cause: he made his followers into heroes fighting for freedom. The no-mask using is a clear illustration of how far this identification of "fighting for freedom" can go, even to the denial of the obvious danger of dying from COVID. This shows that our symbolic allegiance is more powerful than the physical. No wonder so many people are ready to "die for a cause," often with tragic consequences.</p><p>Deniers find force in their cohort, energizing each other and relying on group dynamics to find companionship and strength. Tragically, by forcing our physical separation in lockdowns, the pandemic worked as a catalyst to the deniers, their perceived "loss of freedom" bringing them closer together to the point of making them all believe in the heroic dream of a power takeover. The attack on the Capitol on January 6th is the epitome of denialism in modern America, from both sides of the aisle: the perpetrators who marched and pillaged and those who failed to read the obvious signs of mounting danger, denying the reality in front of them.</p>
Science denial — or is it science negation? A protest banner set up in front of the Republican National Convention Headquarters on August 24, 2020, in Washington, DC.
The opening lines of Smartmatic's $2.7 billion lawsuit against Fox News lay bare the culture of denial in the US.
- Smartmatic, an election technology company, has filed a $2.7-billion-dollar defamation suit against Fox News for making false claims about its voting machines during Fox's dishonest campaign against the 2020 US presidential election results.
- The lawsuit opens with three powerful statements of fact: A scientific truth, a mathematical proof, and an objective political fact: More people voted for Joe Biden than for Donald Trump.
- We owe the Smartmatic lawyers a debt of gratitude for so cleanly demonstrating what this ongoing election battle is all about. What is at stake is not a political ideology. It's a fight to acknowledge the shared reality we all live in.
Voting is a democratic mechanism that helps us "get along." Here, former vice president Mike Pence and house speaker Nancy Pelosi preside over a joint session of Congress to certify the 2020 electoral college results.
Credit: Erin Schaff / POOL / AFP via Getty Images<p>This "how to get along" question is an old, old problem for humans, and we have tried many approaches including kings, dictators, and tyrants. Voting was a pretty radical idea when it was first tried out in ancient Greece. But by the time it was proposed in places like the nascent United States, it had taken on an entirely new character. Proposals for democracy in the 18th century emerged from the constellation of ideas we now call the Enlightenment. More than anything else, Enlightenment-era thinkers believed they had found a path toward a better world. It was a path laid down by reason and by science.</p> <p>For <a href="https://www.theguardian.com/books/2018/feb/11/reason-is-non-negotioable-steven-pinker-enlightenment-now-extract" target="_blank" rel="noopener noreferrer">Enlightenment</a> thinkers, "knowledge, innovation, freedom, and social advancement go together," <a href="https://www.foreignaffairs.com/reviews/capsule-review/2010-03-01/science-liberty-democracy-reason-and-laws-nature" target="_blank" rel="noopener noreferrer">writes Timothy Ferris</a> Thomas Jefferson and Benjamin Franklin saw their new nation as an "experiment" in self-rule. John Adams thought that the data gained from the experiment could be combined with reason to produce a <a href="https://www.goodreads.com/quotes/42294-the-science-of-government-it-is-my-duty-to-study" target="_blank" rel="noopener noreferrer">"science of government."</a> Science as both metaphor and reality were so important to the framers of the US Constitution that they put the patent system into the document's very first <a href="https://www.law.cornell.edu/wex/intellectual_property_clause" target="_blank" rel="noopener noreferrer">article</a>. </p> <p>The framers of American democracy wanted a political system that would reflect the order and transparency they found in the natural world through science. And in science, such order and transparency occur because there are clear mechanisms for establishing facts. Even more important there are, indeed, facts to be found. There is a shared reality we all inhabit regardless of religion or disposition or party affiliation. In this way, the number of votes cast in an election is an objective fact. By establishing the system for self-governance and agreeing to its rules, a tally of votes cast for a candidate is a reality of our shared civic space. </p> <p>What denial, in all its modern forms, wants is to destroy that civic space. It hopes to break the agreement about shared reality. But, in doing so, it also destroys the capacity for science, our most powerful tool for understanding the world.</p>
American teacher John Thomas Scopes (second from left) standing in the courtroom during his trial for teaching Darwin's Theory of Evolution in his high school science class. Dayton, Tennessee, 1925.
Credit: Hulton Archive/Getty Images<p>I've been writing about science denial for <a href="https://www.nytimes.com/2013/08/22/opinion/welcome-to-the-age-of-denial.html" target="_blank">some time now</a>. It began a century ago in arguments over evolution. After <a href="https://www.history.com/this-day-in-history/monkey-trial-begins" target="_blank">the famous</a> <a href="https://www.npr.org/sections/13.7/2011/07/13/137792164/inheriting-the-wind-film-science-and-religion" target="_blank">Scopes Monkey trial</a>, it seemed that battle was over. It was climate change, however, that mainstreamed denial in the modern era. Through <a href="https://www.merchantsofdoubt.org/" target="_blank">climate denial</a> we first began to see people in positions of power make blatantly false claims about the shared reality revealed by science. It was, more than anything, a rejection of the possibility of knowing anything, of having <a href="http://www.publishersweekly.com/978-0-19-046941-2" target="_blank">expertise</a>. Then, over the last five years, denial exploded beyond claims of science to touch all domains of public life including the most basic facts about the world (i.e., which inauguration was attended by more people). The "Big Lie" about the 2020 elections was the most egregious attempt to deny that there are shared facts about a shared world.</p> <p>By explicitly linking facts about the physical, mathematical, and civic worlds, the Smartmatic suit explicitly rejects that denial. While it's impossible to know what will happen to their legal case, we owe the Smartmatic lawyers a debt of gratitude for so cleanly demonstrating what this ongoing battle is all about. What is at stake is not a political ideology. It's not about Democrats or Republicans. Instead, what lies before us is an effort to reestablish the core beliefs that underpin the continuing global experiment in democracy and science.</p>There <em>is</em> a world we share, and we <em>can</em> know something about it. We can agree on what we know and, most importantly, we can use that knowledge to make things better for everyone.
Pandemics have historically given way to social revolution. What will the post-COVID revolution be?
- The US is approaching 500,000 COVID-19 deaths. What can we learn from one year of loss and chaos?
- The lessons are clear. Among them are realizing our fragility as a species, our codependence as humans, and the urgent need to move beyond social injustice and inequity.
- As with the Renaissance following the Black Plague of the 14th century and the explosive creativity of the 1920s post Spanish influenza, this is our turn to redefine the course of history. Let's not mess this up.
First, some facts.<p>This is the biggest existential threat of our generation. We didn't face the tragedy of two world wars and, so far, escaped the ongoing threat of nuclear warfare. It's important to compare the tragedy that we are going through now with the devastation of the Spanish Influenza of 1918, with numbers that seem almost incomprehensible. It is estimated that about <a href="https://www.cdc.gov/flu/pandemic-resources/1918-pandemic-h1n1.html" target="_blank">500 million people</a>, some one-third of the world's population then, were infected by the virus. Of those, 50 million—10 percent—died worldwide, 675,000 of which were in the US. In today's numbers, this would mean that about 2.4 billion people would be infected, and 240 million would die. At the time of writing, there have been about 109 million confirmed infections (surely an underestimate) and <a href="https://www.worldometers.info/coronavirus/" target="_blank">2.4 million deaths</a>. While the numbers are much better worldwide this time around, this data doesn't make us feel any better. We are approaching half a million deaths in the US, another incomprehensible number, getting closer to the number of US losses during the Spanish flu. Denial, the lack of federal leadership, the top-down silencing of scientific evidence and support, complacency, science denial—these are all to blame.</p>
Science is essential.<p>A global pandemic of this magnitude is first and foremost a public health issue and the first line of defense is through science and public policy working in tandem. The fact that we are faring comparatively better than in 1918 speaks to the power of medicine to save lives: ventilators, antiviral drugs, better sanitation, better understanding of how this virus operates. The numbers could have been much better if health policy measures had not become politically weaponized and added to the current ideological divide with tragic consequences. The fact that we now have extremely effective vaccines, some using entirely novel technologies, speaks again to the power of science to save lives. This is a moment to celebrate science in service of humanity's greater good.</p>
We need to rethink who we are.<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTY1NDg2My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2NzUxMjM1OH0.tvU-1kMIO1hvjow2pNKKe_i3C526z6cKcYXAGvBGeXQ/img.jpg?width=980" id="c1474" class="rm-shortcode" data-rm-shortcode-id="62c7f27c3a3ce0239daf7342828c0172" data-rm-shortcode-name="rebelmouse-image" data-width="2000" data-height="1125" />
Earth has existed for 4.5 billion years; our species, Homo sapiens, has existed for about 200,000 years.
Credit: desdemona72 via Adobe Stock<p>The pandemic has exposed our perennial fragility as a species. Nature operates under rules that don't include compassion for loss of life. We are not above nature. Technology may give us the impression that we can control the ways of the world, but we are still very much part of the process of natural selection, getting ill as mutant forms of this virus and others create new public health challenges. Natural selection is an endless battle for survival. We cannot trick it into a permanent stop, only into momentary halts. Indeed, as the environment changes, new forms of life emerge and not all of them will be beneficial to us. The melting of the permafrost is bringing up diseases that hit our distant ancestors and against which we are defenseless. Rethinking who we are calls for humility. Humility in the face of our limited resources, humility in the face of forces that are much more powerful than we are. We can dig deep holes and tunnels through mountains, cut down forests and make oceans retreat. But every one of these actions has a profound environmental impact that costs us dearly. Rethinking who we are calls for a reframing of our relationship to the planet. Earth has existed for 4.5 billion years; our species, <em>Homo sapiens</em>, has existed for about 200,000 years. We have just arrived here. Earth will continue without us. We can't continue without it, space exploration notwithstanding. The future of our project of civilization depends on our rethinking of our planetary role.</p>