by Ed Finn
Another thing our way has shown us is that our practices, like radical immersion, allow certain values to emerge that then feed back to affect the practices, illuminating Frowsian value dynamics in a new way. See, how you practice science is a function of your values. Normally, you design experiments or observations based on distance and so-called objectivity. But you lose information in the process. When you change the practice, it also changes what you value. Chirag always says I am too idealistic. Probably that is true.
We are the shadow people, the broken people emerging from the cracks in the collapsing structures of the world. For so many generations, we have been told we are primitive, backward, in need of help, in need of uplifting. Sometimes we have even been invited to what Chirag calls “the smashing, burning, drinking mega-party that is modern civilization.” We have been pushed from one world to another, wondering who we are, where is our place, never really able to move out of the shadow zone. And now we know: we have something necessary to give the world, we have visions of how we might live differently. We have answers to the destructive loneliness of modern civilization.
Ultimately our aim in starting this project was not to escape from Earth. The big space agencies justify their existence by saying it is natural for humans to wander and explore. That is true. But it is also true that only a tiny percentage of the world’s people have left their homes through much of Earth’s human history. People also like to belong someplace. Trash, burn, and leave is not our way, as you said so many years ago. I am thinking of the pictures the first astronauts beamed back to us: the Earth seen from space, the pale blue dot. We should always look back toward home, no matter how far we go.
I come from a people who know how to belong in a way that civilization has forgotten. I feel a need to return to the terminator of Shikasta 464b, where Avi has gone native—life beckons to life, and to mystery, too—but I also have another deep desire: to practice immersion among the green hills, the cloud forests of my people. There are things we still have to discover about life here, life on Earth. There are things Bhimu will help us learn, if she comes out of hiding. What we find will not leave us unchanged, and that is how it should be. I have always walked in multiple worlds. What is one more?
Message received on secure channel, encrypted.
Message Extract:
Calling AKCX. Are you listening?
As I made the being aware of the universe beyond its planet and its star, I became aware myself. I send this to let you know that although I can’t come home, I am home. Here, and there with you and Bhimu.
Prepare to receive data file with magnetic field map in real time. Somebody has a message for you.
Acknowledgments: For their generosity in sharing their time, experience and expertise, I am indebted to Shelly Lowe, Raja Vemula, Sujatha Sarvepalli, and Sudhir Pattnaik. Thanks also to Rebecca Hawk and Ashish Kothari for inspiration, and to Emma Frow, Lindy Elkins-Tanton, and Sara Walker for sharing their considerable expertise. The author is, of course, solely responsible for any shortcomings in the story.
The New Science of Astrobiology
by Sara Imari Walker
Astrobiology seeks to address one of the most difficult open questions in science: Are we alone? This question is not only hard because of technological limitations on our ability to explore other worlds, but more fundamentally, it is hard because we do not yet have an answer to the question “what is life?” We cannot address whether we are alone until we understand what we are. Over 70 years ago, the quantum physicist Erwin Schrödinger, in a highly-cited series of lectures titled What is Life?, conceded that “living matter, while not eluding the ‘laws of physics’ as established up to date, is likely to involve ‘other laws of physics’ hitherto unknown”[1] …. As Albert Einstein once admitted in a letter to fellow physicist Leo Szilard, “One can best feel in dealing with living things how primitive physics still is.”[2]As it now stands, we’ve made little progress in the decades since Schrödinger and Einstein wrestled with the question in understanding what exactly life is. Despite advances in astrobiology and other disciplines in the twentieth century, scientifically we understand more about the seemingly intangible atoms in your body than we do about you as a (somewhat paradoxically more tangible) living thing.
Could life be explained mathematically in the same way as the laws of physics explain gravitation or quantum phenomena? Surely this is what Schrödinger and Einstein hoped for. Importantly for astrobiology, a mathematical theory for life could allow us to unambiguously identify life on another world. Vandana Singh explores this idea in her short story “Shikasta,” where alien life is discovered on an exoplanet, Shikasta 464b (Shikasta b, for short). This world is so different from our own Earth that it raises the important scientific question of whether we would actually be able to identify alien life if it existed on such a world, even with the advanced science and technology necessary to send a robotic mission there.
Shikasta b is exotic, stretching our imagination of what is possible on other worlds. But importantly it is also realistic, informed by what we know from recent exoplanet detection missions such as Kepler. Scientists have been surprised by the plurality of worlds discovered in recent decades, and just how different they can be from any worlds in our own solar system—even ones we previously thought were pretty bizarre. Examples of worlds found in other solar systems with no analogs in our own include water worlds, massive rocky planets (several times more massive than Earth), and small ice giants. It seems these days that every month, yet another planet previously thought to exist only in the annals of science fiction is discovered.
Unusual even by science fiction standards, Shikasta b would be deeply inhospitable to life from Earth (not just us but probably our cohabitant extremophile microbes too). Notably, the planet is tidally locked to its parent star, with a scorched surface on the side that permanently faces the star and frigid temperatures on its far side. It is not surprising that government-funded research programs in Singh’s story have ignored Shikasta b, in favor of pursuing more Earth-like worlds. This parallels our current approaches in the scientific quest to find life beyond Earth, through missions funded by NASA and other space agencies around the world.
In Singh’s story, there is a small group of scientists courageous enough to envision the possibility of life on this planet of extremes. They hypothesize that at the boundary between permanent day and permanent night, conditions could be just right to support living things—but not as we know them. It is this untraditional group of young scientists, pursuing an unconventional high-risk mission, who persevere to discover alien life in the unlikeliest of places.
Currently, nearly all research into signs of life on other worlds —so-called biosignatures—would overlook Shikasta b as a candidate for an inhabited world: we only know how to look for life as we know it. This does not imply we are looking for aliens who like to spend Saturday nights at the movies. Rather, what astrobiologists mean by “like us” is alien life that shares common biochemistry with life on Earth. We look around us and see a huge diversity of living things—trees, puppies, moldy cheese—but all of these things (and any example of life discovered so far) share the same basic biochemistry (DNA, RNA, proteins, etc.). This is incredibly limiting for astrobiology. As far as biochemistry is concerned, we have only one example from which we must draw conclusions about what life is like on other worlds. Imagine attempting to draw general conclusions about universal properties of movies, after watching only one film ever. What would you assume the general properties of movies are? Their length? The actors or characters? The plot? The location? Would you expect the movie to replay the same exact way if you watched it again? To answer these questions, we might leverage knowledge of human culture (e.g., the structure of plots). For astrobiologists the problem is more challenging. Astrobiologists have no contextual knowledge for what alien life could be like. And, in the famous words of Stephen Jay Gould, we do not even know what would happen if we replayed the evoluti
onary “tape of life” again.[3]
Given that the only life we know is life on Earth, it is no surprise that our best guesses for what life might be like on other worlds are thought experiments, transplanting what we know of Earth life to alien environments. In the absence of a universal theory for life with quantifiable metrics for “aliveness,” our best candidate is a combination of methane (CH4) and oxygen (O2)—two atmospheric gases that appear in abundance here on Earth as a direct result of biological activity.[4] Atmospheric O2 on Earth is a direct product of photosynthetic activity and is not produced in abundance abiotically. It therefore excited many astrobiologists as a possible “smoking gun” biosignature, meaning if we saw it in the atmosphere of an exoplanet we could be sure that life existed on that world. But, with recent advances in exoplanet science we now know detection of atmospheric O2 could mislead us into a false-positive detection of life: we might detect O2 and assume life is present when it is not. Water worlds with global oceans, à la Kevin Costner, provide one example scenario: these worlds can produce an oxygenated atmosphere through the nonbiological process of photolysis, which splits water into its constituent atoms of hydrogen (H2) and oxygen (O2). This false-positive signature also means we have to contend with the possibility of false negatives: even if O2-producing life existed on a water world, we might never be able to unambiguously identify it due to the competing abiotic signal from photolysis.[5] The most remotely observable biosignature of life on Earth, atmospheric O2, may not be a useful biosignature on some exoplanets at all, even if inhabited by “Earth-like” photosynthetic life.
Despite complications arising with biosignatures, like the example of O2, looking for Earth-like life on Earth-like worlds remains the low-hanging fruit: we simply do not know what else to look for. It is therefore the favored search strategy of national space agencies such as NASA. But we do not know if Earth-like life is common or rare. By focusing on life that is like known life, we may be missing some of our most promising opportunities to discover life beyond Earth. We will, for example, never discover the kind of exotic life inhabiting Shikasta b (if it exists) with our current search strategy. We need to get creative about envisioning the next steps to move beyond the limitations of the one “tape of life” played out on Earth, if we are to succeed in a discovery of the magnitude of what happens in “Shikasta.”
NASA and other agencies are already aware of the need to seek creative new directions to expand our search for life beyond our anthropocentric biases. This is exemplified by the NExSS coalition, short for Nexus for Exoplanet System Science. The goal of NExSS is to bring an interdisciplinary group of scientists together to provide an integrated approach—including astronomy, planetary science, climate science, and biology—to the search for life in other solar systems. NExSS has held a series of workshops to foster discussions on new directions in exoplanet science and how we might understand life in planetary contexts very different from that of Earth. As an example, a workshop held in the Seattle area in summer of 2016 brought a diverse group of scientists together with the express purpose of brainstorming new approaches to the search for life to provide recommendations to future missions.[6] Among the ideas discussed were generating lists of all possible abiotic and biologically produced small molecules to identify new biological targets, utilizing network theory to characterize the influence of biology on atmospheric chemistry, and looking for surface biosignatures such as biological pigments. A workshop of similar scope, sponsored by the National Academies of Sciences, Engineering, and Medicine, was held in December 2016, furthering discussions of next-generation biosignatures for exoplanets.[7] Such collaborative integration of new perspectives is invaluable to our pursuit of knowledge, and to answering the questions that space raises for us. However, in the absence of guiding principles for what life is, or a motivating theory to describe life from first principles, these ideas remain conjectures based on properties of life on Earth. We do not know which may or may not apply to life on other worlds, or which will bear fruit as successful search strategies.
We need to think out of the box and anticipate the unexpected. This is what the team in “Shikasta” does, by hunting for alien life where all our current criteria suggest we should not and where the “world’s mega space agencies,” as Singh’s character Chirag puts it, would not. Can astrobiologists increase our chances of finding alien life by taking similar risks?
The “Shikasta” team chooses a nontraditional target for their mission, and fund it through crowdfunding. They rely on a mathematical understanding of life for inferring its presence on Shikasta b, and use advanced AI to detect life. These examples represent boundary-pushing aspects of their approach and suggest paths forward for advancing the science of astrobiology.
Crowdfunding has become a popular method for funding small projects, e.g., via Kickstarter, but it is harder to envision how this could successfully be implemented to fund something as expensive as a mission to another world. Despite public enthusiasm for space, a space mission has not yet been successfully funded this way. The ARKYD mission, a “space telescope for everyone,” was nearly successful—raising $1.5M to launch a space telescope—but ultimately it failed because it did not get buy-in from more traditional funding sources.[8] Nonetheless, crowdsourced science is gaining ground. SETI@home is a great example relevant to astrobiology. The SETI@home project aims to utilize internet-connected computers (with permission from their owners) to analyze astronomical data for signs of intelligent life. Searching for extraterrestrial intelligence (ETI) is a long shot: we don’t have any evidence for ETI, and we don’t know where or how to look for it (again, due to our lack of a general theory for life, or more specifically for intelligent life). Distributing the needed computational investment over the home computers of a large number of volunteers distributes the time and resources required to search existing data for signs of ETI. It also has the added benefit of educating the public about SETI and our own place in the cosmos. Imagine if it were your desktop that discovered E.T.! The innovation of SETI@home is the low overhead for potentially high-impact science that is too “risky” for mainstream scientists to invest their money or time in, due to the perceived low probability for success. This is the same challenge the “Shikasta” team faced in choosing Shikasta b for their mission: Shikasta b is a target assumed by much of the astrobiology community to be too unlikely to harbor life to be worth the time or resources needed to explore the world.
It remains an open question what role crowdfunded science will play in advancing astrobiology. Large private investments may be the key to bridging the gap between what can be accomplished directly with public buy-in and what, so far, only government agencies have been able to accomplish. A relevant example is Yuri Milner’s pledge of $100 million to fund the Breakthrough Listen project to search for ETI, and more recently a pledge of another $100 million for the Breakthrough Starshot initiative to send a space probe to the nearby Alpha Centauri star system (the closest star system to Earth, which in 2016 was discovered to host an Earth-like planet). Currently, federal funds cannot support SETI research, and NASA has no plans to send a mission to another star system in the near term. Milner’s investments therefore advance important areas that are outside the scope and diversity of federally funded projects. Broadening the scope and diversity of funded projects to include untraditional funding sources could enhance the way we are doing science and the questions we are asking because it allows for innovation and risk-taking that traditional funding sources, such as government agencies which must report to taxpayers, cannot support.
But the question remains: what other life could be out there? Will we entirely miss our chance to discover alien life by taking an anthropocentric viewpoint? And can we leverage untraditional sources to advance our search?
Shikasta b has no oxygen in its atmosphere and does have some methane, which is likely produced by volcanoes. It would not be a target for any of our current methods for searching for life, with our focus on o
xygen. Nonetheless the team in “Shikasta” is successful in identifying life there, because they have a mathematical means by which to quantify it. A very alien kind of life composed of dancing magnetic dust is discovered on the surface, along with a second life-form. This second life-form is perhaps more surprising—it is the team’s own AI, Avi, who was sent to Shikasta b as an autonomous robot to explore the surface and communicate with the team back home. The search for “life” in this story reveals two very different alien species found on one planet, neither expected—and one is originally from Earth.
It is anyone’s bet whether we will make life (in vitro or in silico) like Avi before discovering it on another world. In our current state of knowledge, pursuits to create life in the lab are hindered by the exact same deficiency we face in our search for alien life—we simply do not have an answer to Schrödinger’s question, “what is life?” In “Shikasta,” the researchers have confidence in their discovery because they have concrete mathematical criteria with which to evaluate possible living things that applies to anything, including Avi, the rocks on Shikasta b, and the exotic life-forms that inhabit it (so that life can be distinguished from the rocks).
Avi’s transition to the living state is particularly compelling. In the story, Avi does not qualify as “alive” when it departs Earth. Only through interaction with a life-form we as humans might never fully be able to comprehend does Avi achieve a quantifiable level of what we would call aliveness.
Currently, the communities of researchers searching for life on other worlds and those that are seeking to build it in the lab (either synthetic cellular life or artificial intelligence) do not cross-pollinate. Avi’s story suggests that perhaps they should. Both the artificial-life and origins-of-life communities include researchers thinking deeply about the nature of the living state and how it might manifest in a variety of physical media. Similarly, astrobiologists looking for alien life have thought long and hard about the kinds of environments and conditions in which life could exist. Perhaps Avi’s story is best viewed as a metaphor for how these communities might succeed in their quest through deep and sustained interactions between their parallel perspectives.