Yves here. I was a very active science fiction reader in my teens and a fair chunk of my adulthood. But I am not at all optimistic about humans finding life forms, as we choose to define it, outside our solar system, given the huge distances versus our very short lifespans. Separately, however, most commentators have a blinkered notion of what life is, as in it is presumed to be biological. Why aren’t stars on the list? Could they not be life operating on a very different time scale than ours?
By Sarah Scoles, a science journalist based in Colorado, and a senior contributor to Undark. She is the author of “Making Contact,” “They Are Already Here,” and “Countdown: The Blinding Future of 21st Century Nuclear Weapons.” Originally published at Undark
Lisa Kaltenegger’s lab has a bit more color than a typical research facility, filled as it is with a plethora of bright glassware. It’s the kind of rainbow array you might expect to see in the lab of a life scientist. But Kaltenegger isn’t a life scientist, nor is she cultivating colorful organisms in these tiny, transparent homes for biological study. She’s an astronomer, interested in learning how masses of microbes located on distant planets might look through a telescope.
Kaltenegger has populated Petri dishes and other vessels with organisms like algae, samples of which she cajoled out of her life science colleagues at Cornell University. Each species changes the hue of its environment in a particular way, transforming the deserts, ice, or hot springs from which it came — or, in this case, the color scheme of Kaltenegger’s lab. Ocean algae, for example, can create a crimson bloom, while some hot-sulfur-spring-dwellers produce a mustard shade.
Kaltenegger’s lab is part of the interdisciplinary Carl Sagan Institute, which she founded in service of finding life in the universe. Her new book “Alien Earths: The New Science of Planet Hunting in the Cosmos” details the research that aims to find such life forms, and understand the planets they may inhabit — a pursuit that, for her, sometimes begins with those colorful organisms.
After a given group of organisms has grown enough, Kaltenegger and colleagues load it into a backpack and take it to Cornell’s civil engineering department. There, the scientists can use remote-sensing equipment to see the samples as a telescope would — measuring the different color patterns of light that result. That way, the idea goes, scientists can recognize potential alien organisms — which could, hypothetically, resemble algae and algae’s alterations of Earth — at a distance, based on their chromatic fingerprints.
The information about their color then gets plugged into computer models that Kaltenegger creates of planets, both actual and hypothetical. “A few keystrokes let me move the planet closer to the star, manipulate the color of its sun, heighten its gravity, create worldwide sand dunes, oceans, or jungles, and add or remove life-forms,” Kaltenegger writes. “I am creating worlds that could be and the light fingerprints to search for them with our telescopes.”
In “Alien Earths,” Kaltenegger lays out the state and stakes of this search, while exploring the array of planets in this solar system and beyond, all with the goal of answering that ultimate query: Are we alone? “The question should have an obvious answer: yes or no,” she writes. “But once you try to find life somewhere else, you realize it is not so straightforward. Welcome to the world of science.”
Kaltenegger begins “Alien Earths” by setting up the different ways that people have thought about life in the universe — or, rather, the lack of evidence for it so far. But the book’s substance is in investigating how and where life might appear in the universe, and how humans might recognize it. In this pursuit, it bounces from planetary evolution to exoplanet studies, from biological evolution to telescope technology, the text as interdisciplinary as her institute.
It’s a lot of ground to cover, and the flow of the book is not always tightly organized in a thematic way. But what the book may lack in structural coherence, it makes up for in vivid details that take readers to the titular worlds — and can lead them to view their own planet at a remove, as an alien would through its own telescope.
Take the imaginary planet that begins the book: One where a whole hemisphere is always dark, the other always light: “You wait for the sunset and the darkness of night, but they never come,” she writes. “To experience nightfall, you have to travel for days to the far side of this distant planet, a place of eternal dusk.”
The text shines most when Kaltenegger writes about her own research, which is fascinating in its inventiveness. In the digital planets she creates, informed by her experiments, she acts as a kind of god, manipulating them to her liking and curiosity. “I can cover the oceans with a green algae bloom or dot continents with yellow microbial mats,” she says. “Without leaving my office, I can create new worlds.”
Kaltenegger explains this complex science in a straightforward, sometimes lyrical, and often humorous way. For instance, when discussing whether and how humans might communicate with extraterrestrial life, she writes that “the experience might end up being like a human trying to talk to a jellyfish. I’ve attempted that; the results were less than promising.”
The book also doles out the kind of big-picture cosmic facts that blow the minds of each new generation of pop-science readers, as when she discusses how the speed of light affects our perception of the stars: “Because light needs time to travel through the cosmos, you can find a link to your own past in the sky,” she writes. “There is a star in the night sky whose light was sent out when you were born and is just arriving now.”
Sometimes, the humor and the mindblowers come in one package, as in Kaltenegger’s description of the solar system whizzing around the galaxy’s center. “If you ever feel stuck,” she writes, “remember: cosmologically speaking, you are not. You are speeding through the cosmos. And you are part of it.”
In that cosmos, scientists have found more than 5,000 distant planets in the past 30 years, a wave of discoveries that Kaltenegger charts, with descriptions as rich as her imagined creations. For example, the planet CoRoT-7 b, discovered in 2009, is so hot that it melts its own rocks. These liquefied rocks evaporate, then fall back down to the cursed ground as lava rain.
Kaltenegger has experimented with a similar lava planet in her lab, to again understand how a telescope might see such a place: Her team picked 20 different rock varieties that might be found on planets, then mixed them in powder form to get the compositions for the type of planet they wanted to create. When placed on a heated metal strip, they become small-scale lava — a linear lava planet, of sorts. “The worlds we create are so small, they can easily fit in the palm of my hand,” Kaltenegger writes. She and colleagues then try to figure out how that lava would look large-scale to a telescope, so they can compare that signature to sights they actually see.
Readers may be surprised, though, to find that so much of “Alien Earths” focuses on this Earth and its close neighbors in the solar system. “When we look for life in the cosmos, Earth is our lone key to unlock the secrets of what it requires to get started,” Kaltenegger explains. And so exoplanet scientists actually spend a lot of their time looking closer to home — at the blooming life in their own Petri dishes, the evolution of familiar continents, the record of meteorite strikes, or the ways the atmosphere has transformed over time.
Conversely, studying other planets could reveal more about Earth and how it came to sustain life. Other planets might also serve as cautionary tales: “Exploring space allows us to gather the knowledge to save ourselves from asteroids, from pollution, and from using up the limited resources on Earth,” Kaltenegger writes.
But in her view, the best way for humans to save themselves long term isn’t necessarily to fend off planetary troubles. It’s to get out of here. All planets — alien or not, polluted or not — will someday be rendered uninhabitable: The stars they orbit will go out “in a hot blaze of glory,” boiling life out of existence, or they will slowly get dimmer and their worlds slowly colder. Though this won’t happen to Earth for billions of years, if you would prefer neither, Kaltenegger has a suggestion: “Let’s become wanderers of this amazing universe,” she writes. “It does not have to end in fire or ice.”
I have give up on humans to explore space. I am not sure if this is true but someone said if humans did use 2 percent of the planet gpd starting from the 60 they could have explore our solar system long time go. Now we have lost all the time we had to invent new kind of rockets to go to space. Now neocons control all our policies, so we are going to ww3 sooner or later. Looking what usa is doing in Taiwan is good example, they are arming Taiwan, so Taiwan can go inpendense and then china will then have to invade taiwan that is usa plan. So how can any country concentrate on space exploration when you have neocons planning to take you down
My more cynical side observes that the Chinese space program is a small step to the “expanded planet” idea. The near earth orbit zone is already being used to improve Terrestrial living. Space satellites for weather forecasting is a small sample of what is possible. Satellite communications is yet another. Next up logically are orbital factories for products that can be made better in low gravity conditions.
As for neo-libs and their discontents; a Non Aligned nations orbital weapons platform with purely kinetic “warheads,” no nukes needed, would go a long way to showing just who’s boss around here. (There is lively debate about the need for “bosses” in the first place. The old Enlightenment philosophers and their progeny, especially Marx and Engels, are but the opening salvos in the “War For Primacy.”)
Stay safe.
You have to admit that it is an interesting challenge to think of how life might have evolved on other worlds as this must have happened to some of the worlds discovered so far. If there is a dominate species that is also sapient, there is nothing to say that it will be a primate. Maybe it will be similar to something that we have on Earth or perhaps it will be something else altogether. Then there are more basic questions. Animal, vegetable or mineral? Will it utilize DNA chains like life has here on Earth? Thinking about such questions might help us focus on some vital questions that we have right here. Such as what is it that constitutes ‘life’? What is the definition of sentience? Such questions will need answering if we ever have to face a First Contact situation one day.
For some time I had a son-in-law candidate who studied exobiology, and I must admit I couldn’t resist on teasing him on selecting an area that studies things that could exist but we can never find out. We he cooled down we had some interesting discussions, though.
The biggest news of this century was the discovery of enough exoplanets to estimate a staggering 10 to the 23rd habitable planets in the observable universe. This number makes the notion of physical exploration of space or a final frontier ridiculous. The explanation of the Fermi paradox is that a sufficiently advanced civilization collapses inward to digital logical space in which it can explore via simulation anything it wishes. Why would any such civilization want to physically visit a primitive planet like ours when there are millions of others, in a similarly precarious condition, that could easily be simulated?
In a way, it may be worse than you think. Lets assume that FTL warp drives exist and we can start pushing out and finding these worlds but more to the point, any civilizations that might be there. So the first planet shows a world ruled by dinosaurs so no chance of civilization there. The next one shows a planet recovering from a nuclear winter as the civilization there had a full nuclear exchange. We just missed them. The next one shows that it is a world of mammals so no chance of civilization for perhaps tens of millions of years. The next shows sentient life but at a Bronze Age level but we can hardly uplift them with 5,000 years of technological development. The next shows sapient lizards but living in caves still. So for the majority of those planets, we would be arriving too early or too late. That can make for a lonely Galaxy that.
Even with warp drive, the numbers make physical exploration absurd. It is like trying to eat in every restaurant on Earth. The reason literature is so satisfying is that it is a highly efficient and instructive simulation mechanism for exploring humanity. No physical travel is required. A sufficiently advanced civilization can take simulation beyond anything we can imagine. If 10 to the 23rd habitable planets is not enough for you, multiple universe theories are the last nails in the coffin of the space “exploration” fantasy. As a British astronomer once speculated, there may be as many big bangs as bubbles in a champagne glass.
“The reason literature is so satisfying is that it is a highly efficient and instructive simulation mechanism for exploring humanity.” Well said. Just the thought of the vastness of time and space makes me want to curl up with a good book and then take a nap. Maybe go fishing later. Making the best of the bubble one’s in is as good as it gets.
Looking for a good book? Plenty in Borges’ “Library of Babel,” or so I hear…
Thanks, I’m getting it from my local library.
I’m sorry, this seems like a complete non-sequitor to me. A simulation, no matter how detailed, ultimately isn’t real. Why the assumption that a society would lose interest in exploring reality just because it could entertain itself with realistic fiction? Maybe it just wants to keep exploring reality. Or maybe there’s a material need to keep exploring the universe, resources or something (this one is more doubtful; how much stuff could a civilization really need?)
Yves: “Separately, however, most commentators have a blinkered notion of what life is, as in it is presumed to be biological. Why aren’t stars on the list?”
Then you haven’t read the “Whipping Star” and the”Dosadi Experiment” by Frank Herbert or the “Bowl of Heaven/Shipstar/Glorius” trilogy by Gregory Benford & Larry Nieven
In the Whipping Star, the expression “hot talk” really takes a new dimesnion…
So yeah, mental exploration and fantasizing is really useful and great.
I would like more fantasizing though about the potential forms of polities that could exist on earth that could make life for everyone, including the biosphere, better. So far only “The Dawn of Everything” makes the cut.
“The next shows sentient life but at a Bronze Age level but we can hardly uplift them with 5,000 years of technological development. ”
The Papua New Guinians lived in the Stone Age and some prcticed canibalism and had as a write of passage for men some very shady practices (check “the Bad Thing” in the British TV show Peep Show.
And now, a generation later, the use cell phones with no problem and travel from one village on a hill to the next, above the impenetrable jungle, via small planes piloted by Aussie bush pilots. Didn’t take 5000 years to adopt modern materialist life… After all, Homo sapiens is “sapiens”…
If you assume FTL travel, then the Fermi Paradox says we must be alone. Because with so many stars out there, the likelihood that the humans would be the first to achieve FTL is extremely small. So if FTL exists, we should see aliens all over the place coming to visit us, but we don’t.
Reading political scifi author Ken Macleod’s Lightspeed trilogy right now, which posits FTL travel for humans and discusses exactly this paradox. I will let you know what the answer is once I finish ;)
https://www.risingshadow.net/book/62342-beyond-the-hallowed-sky
The issue is, how much faster then light travel?
To stumble over aliens at any corner, the Mycelium Drive would be necessary.
And then, there is very little discussion about intergalactic travel, I mean in the scifi universes…
I’ve always thought the Fermi paradox collapsed with the arrival of Cortes in what is modern day Mexico. Aztec scientists explained that there was no civilization to the East because no one had arrived from there in millennia.
Big ship arrives. Oops there goes another paradox
Well, we can view space in ways that the Aztecs couldn’t view distant oceans or Europe, but it’s true that unless alien activities are huge and obvious we might well not notice.
FWIW I saw a claim someplace that the Aztecs possibly did sight an earlier Spanish ship which approached the coast but didn’t land. Supposedly they preserved a story about it, sort of like a UFO account.
Part of the Fermi ‘Paradox’ is that if alien life exists, why haven’t we noticed it. Maybe because space is stupidly vast? Why should we reasonably expect anything to be noticeable at such vast distances? An argument is advanced life would build megastructures but…why? Maybe things the size of planets or even stars that would be detectable don’t actually exist because no civilization has ever found a reason to build them. Just because something epic can be imagined in a story doesn’t mean it must inevitably exist in reality.
It’s like we’ve conjured up something, decided it must exist, and then act perplexed when we can’t seem to find any trace of it.
I resonate with those ideas. Plus whatever kind of thrills you’re looking for, folks give up on earth way too fast. What is anticipated is determined by the professionals-with-imaginations, which does sell but by and large is too shallow to really get interest going. You can’t really even postulate it could, say in the case you wanted to sell berths like futures. It was funny with Google’s Panoramio (now shut down). People weren’t paid for those photos, but there had never been anything like’em! It was so contrary to market logic it had to be done away with. Just slow yourself down enough to look at some of the photos at this site https://500px.com/p/gmallmann
Everything’s here we need (or want). We just give up too fast. However, I think the enduring allure, weak though our conjured versions are, indicates there’s a reason we anticipate a parallel universe of sorts. Remember Michael Toms’ “New Dimensions” show? Yes, I think with more dimensions, there’s a chance things’ll be advanced. Things could be invisible to us as we “see” in our common day to day setting, and yet still be involved in more dimensions.
The part about wandering the universe is fine, so long as you don’t claim it has any relevance to the 8 billion people alive right now. Biosphere 2 shows some of the difficulties in establishing a self- sustaining ecosystem that people would want to live in.
Also, right now we don’t have fusion reactors, let alone antimatter rockets, so probably the only way to the stars if you are willing to spend a lifetime getting there is with an upscaled version of Project Orion. But building a lot of nuclear bombs for a space drive seems like a bad idea from the arms control perspective.
As a science fiction reader I hope we get out there someday, but for now it is irrelevant.
Donald: the only way to the stars if you are willing to spend a lifetime getting there is with an upscaled version of Project Orion.
False. There are other kinds of nuclear rocket design than Orion, which — with all due respect to Freeman Dyson and Ted Thomas — was a remarkably impractical concept.
The most practical such design is in principle also remarkably simple: you mount a reactor in front of an exhaust nozzle and run liquid hydrogen at 22 degrees Kelvin through it so the hydrogen emerges at 2,800 degrees K, at enormous velocity.
The resulting thrust could then be maintained to provide constant acceleration if the reaction mass is available. Maintaining a constant 1G thrust (which by definition Orion couldn’t do with its modus operandi of letting off intermittent nuclear farts to drive itself) then allows that: –
[1] “…At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years ship time, and about 113,000 years planetary time. If the last half of the trip involves deceleration at 1 g, the trip would take about 24 years….”
https://en.wikipedia.org/wiki/Space_travel_under_constant_acceleration
(Note that ship time is time elapsed traveling at mostly near-C relativistic acceleration; planetary time is what it sounds like)
[2] Simultaneously, a 1G constant acceleration creates the effect of 1G shipboard gravity, eliminating the detrimental effects that zero-G weightlessness has on human astronauts who have not been genetically engineered for space travel.
.
***The whole Wiki on ‘Space Travel with Constant Acceleration’ is worth a glance through for those interested but unfamiliar with the technical possibilities. Still, if you ever read the 1960s-era SF novel TAU ZERO by Poul Anderson back in the day, it may not be one of the classics but it does put the idea over.
…meanwhile we foul our nest like no other critter…
I, too, was an avid sci-fi reader early on. I still have a soft side for it, but alas, reality has asserted itself. We need to clean things up on this world, the only home any of us will ever know.
Chris Hadfield was on our local radio station yesterday and said that we are decades away from humans going to Mars.
Until we solve the radiation problem, he is right no matter what Elon Musk might say. A trip to Mars right now would be a slow acting death sentence for any astronauts and would be pointless.
Rev Kev: Until we solve the radiation problem….
Listen, I tell you a mystery: We will not all sleep, but we will all be changed.
— Corinthians 15:51
There will be a speciation. It’s not if, it’s when.
— Chris Mason, Chair of Steering Committee, NASA GeneLab
So, NASA’s year-long Twins Study compared identical twins – Scott and Mark Kelly – while Scott was in space and Mark was on Earth.’
https://www.nasa.gov/twins-study
For starters, note that the ISS, where Scott Kelly spent his year in space, is still very much within the protection of the Earth’s magnetosphere (as was the Moon for the Apollo astronauts), and once beyond that protection solar space is filled with solar and cosmic radiation, up to and including coronals and solar flares. A couple of chastening tidbits from the Twins Study —
[1] When Scott Kelly closed his eyes to go to sleep at night on the ISS, he could see streaks of light, as if there were shooting stars behind his eyelids. These were the HZE particles (HZE ions) blasting his retinal cells and passing through his eyes, with all the concomitant cellular damage that implies.
[2] For most of the mission and when he came back down, Kelly had the highest levels of inflammation markers and cytokine stress the doctors had ever seen.
Consequently, this guy, Christopher Mason, a principal investigator on the project —
https://en.wikipedia.org/wiki/Christopher_E._Mason
— has a 500 year plan to genetically engineer Homo Astronauticus.
Yup.
He has a book out about it, The Next 500 Years: Engineering Life to Reach New Worlds, from MIT Press.
https://direct.mit.edu/books/monograph/5121/The-Next-500-YearsEngineering-Life-to-Reach-New
‘Separately, however, most commentators have a blinkered notion of what life is, as in it is presumed to be biological. Why aren’t stars on the list? Could they not be life operating on a very different time scale than ours?’
I would think about it terms of power density and complexity relative to surroundings. Complex structures arise in consequence to potential energy differentials which they evolve to dissipate more effectively; what physicists call dissipative structures. The convection cells in the atmosphere that form when the earth heats enough are an example, the uniform atmosphere breaks up into a more complex pattern of convection cells and increases the flow of energy. Hurricanes are an example. The fractal nature of stream beds in mountain ranges are another example. It turns out that a fractal structure is most efficient at getting water from high to low potential (altitude). The complexity rises with power density (J/s/kg or Watts/kg). The physicist, Eric Chaisson, studies this. Here is a plot of power densities:
https://www.researchgate.net/figure/Energy-rate-density-PH-m-for-a-wide-spectrum-of-systems-observed-throughout-Nature_fig2_263048576
Turns out organisms have a higher power density than stars and brains have higher power density than the rest of the body. How can that be given the heat of the sun? The sun is much more dense (grams/volume). To broaden the idea of life I would look for unusually high power densities relative to the surroundings. But, are hurricanes a form of life then? What dissipation rate/complexity level would need to be attained for us to call it life?
Ecologists have noted that organisms that dissipate energy more effectively (have more power) are more successful in competition. The maximum power principle. Historians note the winners in wars physically utilize more power. By the way, by this measure China is about 60% more powerful than the US. In 2021 China used about 165 quadrillion BTUs of energy, while the US used about 98 quadrillion BTUs of energy. We can see the results of this in their manufacturing capacity. I would predict on this measure alone that China would win a non nuclear war with the US. Handily. Is China’s power density and therefore complexity greater. This is harder to say. We have to figure out the mass of economies. This is the kind of thing Chaisson estimates.
Really nice comment, but what does this mean?
“Turns out organisms have a higher power density than stars and brains have higher power density than the rest of the body. How can that be given the heat of the sun? The sun is much more dense (grams/volume).”
I think the age of things certainly must matter. The universe is 14 billion years old, though some estimates say its older, the earth is 4.5 billion years old, and humans have been around for about 300,000 years.
I should think there are life supporting planets millions of years older than the earth, and if so, it’s possible many have had intelligent life for say 1-million more years than humans on earth. Thus, they surely figured out by now how to make airplanes where door panels don’t blow out.
Moreover, there’s only so much iron, copper, lithium, and other resources, most of which humans will likely exhausted in a few hundred years. And these elements would be available on other earth type planets as well. So it’s imperative to figure out how to survive without the things we currently take for granted.
The other conclusion is there is little or no intelligent life in the galaxy because intelligent beings exhaused their world before they understood how to make it sustainable. In other words, intelligence is merely self-destructive behavior.
I’m inclined to believe in a host of intelligent species strewn across the vast expanses of the universe, all at varying degrees of complexity, and all very good at keeping quiet and observing their surroundings, lest they provoke the wrath of a hostile and more advanced civilization.
In this purely hypothetical scenario, a self-interested species might be loathe to quash a potentially threatening and less advanced civilization, not out of ethics or fear of retaliation by the weaker species, but simply because doing so might alert a more advanced species to their presence and hostility.
Sort of a big game of prisoners dilemma, but where instead of ‘mum’ and ‘snitch’ its ‘let live’ and ‘quash’, with an unknown number of players lurking in the void and potentially observing your actions.
Reminded me of Isaiah 40:26
Lift up your eyes to heaven and see.
Who has created these things?
It is the One who brings out their army by number;
He calls them all by name.
Because of his vast dynamic energy and his awe-inspiring power,
Not one of them is missing.
Bacteria and virus’s are such successful life forms on earth, that they seem likely to exist out there.
Not sure how easy to get from single cells to multi-cellular – but organisms that are aggregates of single cellular creatures like jellyfish suggest not too hard.
Also interesting, intelligence has evolved three different ways on earth – Mammalian and the associated evolutionary chain, octopus (distributed brain), and ants/bees – group intelligence.
Also, symmetry seems to be likely – its almost everything, even in earthworms.
Beyond that, the cost of movie special effects have created in the human imagination bipedal, alien human-istic creatures.
So where are they? Fermi paradox…
“Bacteria and viruses are such successful life forms on earth, that they seem likely to exist out there…”
[ Look to the invertebrate tardigrades. They can be be placed and found in a suspended state in space and revived in a spacecraft or on earth. ]
The thoughtful and always-intriguing science fiction writer and futurist John Michael Godier has an in-depth interview “Are There Other Earths? with Lisa Kaltenegger” [1:08:35] here on his Event Horizons YouTube channel.