From Open Minds TV:
In the search for intelligent extraterrestrials, scientists listen for incoming radio signals and they hunt for Earth-like planets. Some scientists are also looking for megastructures constructed by aliens.
NASA’s Kepler space telescope searches for planets using the transit method–Kepler’s sensors detect dips in brightness caused when an alien planet passes in front of its star from Kepler’s perspective. And this same method is used by scientists searching the universe for alien megastructures.
Simple illustration of a Dyson Sphere. (Credit: Vedexent/Wikimedia Commons)
According to Universe Today, astronomer Geoff Marcy, who was recently appointed to the new Watson and Marilyn Alberts Chair for SETI (Search for Extraterrestrial Intelligence) at the University of California at Berkeley, was awarded a grant to hunt for evidence of Dyson spheres using Kepler data. A Dyson sphere is a theoretical megastructure envisioned by theoretical physicist Freeman Dyson consisting of a giant array of solar panels that would surround a star to harvest its energy.
Scientists hunting alien megastructures are also looking for theoretical structures known as ringworlds. Universe Today explains that ringworlds “would consist of a giant ring in orbit around a star, constructed comfortably inside the star’s habitable zone.”
Whether alien megastructures actually exist is unknown. But as Universe Today points out, “The possibility alone is exciting enough to make it worth continuing to look.”
Actually looking for Ring Worlds and Dyson Spheres would be relatively easy using Kepler data since the Kepler probe uses occluded starlight to detect transitioning alien planets.
The theory is that advanced alien tech would be larger constructions than normal planets and thus, the starlight would be blocked longer. That suggests super-alien cultures.
Sigh. What ever happened to old fashioned UFOs, lol?
From Centauri Dreams:
Astronautics pioneer Robert H. Goddard is usually thought of in connection with liquid fuel rockets. It was his test flight of such a rocket in March of 1926 that demonstrated a principle he had been working on since patenting two concepts for future engines, one a liquid fuel design, the other a staged rocket using solid fuels. “A Method of Reaching Extreme Altitudes,” published in 1920, was a treatise published by the Smithsonian that developed the mathematics behind rocket flight, a report that discussed the possibility of a rocket reaching the Moon.
While Goddard’s work could be said to have anticipated many technologies subsequently developed by later engineers, the man was not without a visionary streak that went well beyond the near-term, expressing itself on at least one occasion on the subject of interstellar flight. Written in January of 1918, “The Ultimate Migration” was not a scientific paper but merely a set of notes, one that Goddard carefully tucked away from view, as seen in this excerpt from his later document “Material for an Autobiography” (1927):
“A manuscript I wrote on January 14, 1918 … and deposited in a friend’s safe … speculated as to the last migration of the human race, as consisting of a number of expeditions sent out into the regions of thickly distributed stars, taking in a condensed form all the knowledge of the race, using either atomic energy or hydrogen, oxygen and solar energy… [It] was contained in an inner envelope which suggested that the writing inside should be read only by an optimist.”
Optimism is, of course, standard currency in these pages, so it seems natural to reconsider Goddard’s ideas here. As to his caution, we might remember that the idea of a lunar mission discussed in “A Method of Reaching Extreme Altitudes” not long after would bring him ridicule from some elements in the press, who lectured him on the infeasibility of a rocket engine functioning in space without air to push against. It was Goddard, of course, who was right, but he was ever a cautious man, and his dislike of the press was, I suspect, not so much born out of this incident but simply confirmed by it.
In the event, Goddard’s manuscript remained sealed and was not published until 1972. What I hadn’t realized was that Goddard, on the same day he wrote the original manuscript, also wrote a condensed version that David Baker recently published for the British Interplanetary Society. It’s an interesting distillation of the rocket scientist’s thoughts that speculates on how we might use an asteroid or a small moon as the vehicle for a journey to another star. The ideal propulsion method would, in Goddard’s view, be through the control of what he called ‘intra-atomic energy.’
Image: Rocket pioneer Robert H. Goddard, whose notes on an interstellar future discuss human migration to the stars.
Atomic propulsion would allow journeys to the stars lasting thousands of years with the passengers living inside a generation ship, one in which, he noted, “the characteristics and natures of the passengers might change, with the succeeding generations.” We’ve made the same speculation here, wondering whether a crew living and dying inside an artificial world wouldn’t so adapt to the environment that it would eventually choose not to live on a planetary surface, no matter what it found in the destination solar system.
And if atomic energy could not be harnessed? In that case, Goddard speculated that humans could be placed in what we today would think of as suspended animation, the crew awakened at intervals of 10,000 years for a passage to the nearest stars, and intervals of a million years for greater distances. Goddard speculates on how an accurate clock could be built to ensure awakening, which he thought would be necessary for human intervention to steer the spacecraft if it came to be off its course. Suspended animation would involve huge changes to the body:
…will it be possible to reduce the protoplasm in the human body to the granular state, so that it can withstand the intense cold of interstellar space? It would probably be necessary to dessicate the body, more or less, before this state could be produced. Awakening may have to be done very slowly. It might be necessary to have people evolve, through a number of generations, for this purpose.
As to destinations, Goddard saw the ideal as a star like the Sun or, interestingly, a binary system with two suns like ours — perhaps he was thinking of the Alpha Centauri stars here. But that was only the beginning, for Goddard thought in terms of migration, not just exploration. His notes tell us that expeditions should be sent to all parts of the Milky Way, wherever new stars are thickly clustered. Each expedition should include “…all the knowledge, literature, art (in a condensed form), and description of tools, appliances, and processes, in as condensed, light, and indestructible a form as possible, so that a new civilisation could begin where the old ended.”
The notes end with the thought that if neither of these scenarios develops, it might still be possible to spread our species to the stars by sending human protoplasm, “…this protoplasm being of such a nature as to produce human beings eventually, by evolution.” Given that Goddard locked his manuscript away, it could have had no influence on Konstantin Tsiolkovsky’s essay “The Future of Earth and Mankind,” which in 1928 speculated that humans might travel on millennial voyages to the stars aboard the future equivalent of a Noah’s Ark.
Interstellar voyages lasting thousands of years would become a familiar trope of science fiction in the ensuing decades, but it is interesting to see how, at the dawn of liquid fuel rocketry, rocket pioneers were already thinking ahead to far-future implications of the technology. Goddard was writing at a time when estimates of the Sun’s lifetime gave our species just millions of years before its demise — a cooling Sun was a reason for future migration. We would later learn the Sun’s lifetime was much longer, but the migration of humans to the stars would retain its fascination for those who contemplate not only worldships but much faster journeys.
Goddard was obviously influenced by his contemporary J.D. Bernal with his The World, the Flesh and the Devil which predicted Man’s spread out into the Solar System and interstellar space with artificial worlds and hollowed out asteroids.
These worlds are needed because such journeys will take hundreds or perhaps thousands of years.
Of course that brings in natural evolution and what these people inside these places will become when they eventually reach their destinations and if they’ll actually have need of them.
An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization, and emergence of novel functional niches associated with existing genes. Linear regression of genetic complexity on a log scale extrapolated back to just one base pair suggests the time of the origin of life 9.7 billion years ago. This cosmic time scale for the evolution of life has important consequences: life took ca. 5 billion years to reach the complexity of bacteria; the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth; there was no intelligent life in our universe prior to the origin of Earth, thus Earth could not have been deliberately seeded with life by intelligent aliens; Earth was seeded by panspermia; experimental replication of the origin of life from scratch may have to emulate many cumulative rare events; and the Drake equation for guesstimating the number of civilizations in the universe is likely wrong, as intelligent life has just begun appearing in our universe. Evolution of advanced organisms has accelerated via development of additional information-processing systems: epigenetic memory, primitive mind, multicellular brain, language, books, computers, and Internet. As a result the doubling time of complexity has reached ca. 20 years. Finally, we discuss the issue of the predicted technological singularity and give a biosemiotics perspective on the increase of complexity.
A very fine paper, except for one thing.
The authors only use one data-set to reach their conclusions.
And I believe they are wrong unless they can prove we live in a simulated universe.
From Centauri Dreams:
Jules Verne once had the notion of a comet grazing the Earth and carrying off a number of astounded people, whose adventures comprise the plot of the 1877 novel Off on a Comet. It’s a great yarn that was chosen by Hugo Gernsback to be reprinted as a serial in the first issues of his new magazine Amazing Stories back in 1926, but with a diameter of 2300 kilometers, Verne’s comet was much larger than anything we’ve actually observed. Comets tend to be small but they make up for it in volume, with an estimated 100 billion to several trillion thought to exist in the Oort Cloud. All that adds up to a total mass of several times the Earth’s.
Of course, coming up with mass estimates is, as with so much else about the Oort Cloud, a tricky business. Paul R. Weissman noted a probable error of about one order of magnitude when he produced the above estimate in 1983. What we are safe in saying is something that has caught Freeman Dyson’s attention: While most of the mass and volume in the galaxy is comprised of stars and planets, most of the area actually belongs to asteroids and comets. There’s a lot of real estate out there, and we’ll want to take advantage of it as we move into the outer Solar System and beyond.
Comets and Resources
Embedded with rock, dust and organic molecules, comets are composed of water ice as well as frozen gases like methane, carbon dioxide, carbon monoxide, ammonia and an assortment of compounds containing nitrogen, oxygen and sulfur. Porous and undifferentiated, these bodies are malleable enough to make them interesting from the standpoint of resource extraction. Richard P. Terra wrote about the possibilities in a 1991 article published in Analog:
This light fragile structure means that the resources present in the comet nuclei will be readily accessible to any human settlers. The porous mixture of dust and ice would offer little mechanical resistance, and the two components could easily be separated by the application of heat. Volatiles could be further refined through fractional distillation while the dust, which has a high content of iron and other ferrous metals, could easily be manipulated with magnetic fields.
Put a human infrastructure out in the realm of the comets, in other words, and resource extraction should be a workable proposition. Terra talks about colonies operating in the Oort Cloud but we can also consider it, as he does, a proving ground for even deeper space technologies aimed at crossing the gulf between the stars. Either way, as permanent settlements or as way stations offering resources on millennial journeys, comets should be plentiful given that the Oort Cloud may extend half the distance to Alpha Centauri. Terra goes on:
Little additional crushing or other mechanical processing of the dust would be necessary, and its fine, loose-grained structure would make it ideal for subsequent chemical processing and refining. Comet nuclei thus represent a vast reservoir of easily accessible materials: water, carbon dioxide, ammonia, methane, and a variety of metals and complex organics.
Energy by Starlight
Given that comets probably formed on the outer edges of the solar nebula, their early orbits would have been more or less in the same plane as the rest of the young system, but gravitational interactions with passing stars would have randomized their orbital inclinations, eventually producing a sphere of the kind Jan Oort first postulated back in 1950. Much of this is speculative, because we have little observational evidence to go on, but the major part of the cometary shell probably extends from 40,000 to 60,000 AU, while a projected inner Oort population extending from just beyond the Kuiper Belt out to 10,000 AU may have cometary orbits more or less in the plane of the ecliptic. Out past 10,000 AU the separation between comets is wide, perhaps about 20 AU, meaning that any communities that form out here will be incredibly isolated.
Image: An artist’s rendering of the Kuiper Belt and Oort Cloud. Credit: NASA/Donald K. Yeomans.
Whether humans can exploit cometary resources this far from home will depend on whether or not they can find sources of energy. In a paper called “Fastships and Nomads,” presented at the Conference on Interstellar Migration held at Los Alamos in 1983, Eric Jones and Ben Finney give a nod to non-renewable energy sources like deuterium, given that heavy elements like uranium will be hard to come by. Indeed, a typical comet, in Richard Terra’s figures, holds between 50,000 and 100,000 metric tons of deuterium, enough to power early settlement and mining.
But over the long haul, Jones and Finney are interested in keeping colonies alive through renewable resources, and that means starlight. The researchers talk about building vast mirrors using aluminum from comets, with each 1 MW mirror about the size of the continental United States. Now here’s a science fiction setting with punch, as the two describe it:
Although the mirrors would be tended by autonomous maintenance robots, the nomads would have to live nearby in case something went wrong… Although we could imagine that the several hundred people who could be supported by the resources of a single comet might live in a single habitat, the mirrors supporting that community would be spread across about 150,000 km. Trouble with a mirror or robot on the periphery of the mirror array would mean a long trip, several hours at least. It would make more sense if the community were dispersed in smaller groups so that trouble could be reached in a shorter time. There are also social reasons for expecting the nomad communities to be divided into smaller co-living groups.
Jones and Finney go on to point out that humans tend to work best in groups of about a dozen adults, whether in the form of hunter/gatherer bands, army platoons, bridge clubs or political cells. This observation of behavior leads them to speculate that bands of about 25 men, women and children would live together in a large habitat — think again of an O’Neill cylinder — built out of cometary materials, from which they would tend a mirror farm with the help of robots and computers. Each small group would tend a mirror farm perhaps 30,000 kilometers across.
The picture widens beyond this to include the need for larger communities that would occasionally come together, helping to avoid the genetic dangers of inbreeding and providing a larger social environment. Thus we might have about 500 individuals in clusters of 20 cometary bands which would stay in contact and periodically meet. Jones and Finney consider the band-tribe structure to be the smallest grouping that seems practical for any human community. Who would such a community attract — outcasts, dissidents, adventurers? And how would Oort Cloud settlers react to the possibility of going further still, to another star?
While by no means is this is a new theory, ( note the Jules Verne story ), it presents the scenario of the very slow spreading of intelligent biological life through-out the Galaxy ( see Slow Galactic Colonization, Zoo Hypothesis and the Fermi Paradox ).
Now here’s a thought; could a potential alien Oort Cloud civilization be the basis of the Ancient Astronaut Theory and the legends of the Sumerian Gods, the Anunnaki?
There’s no hard evidence of that of course, but there are Pluto-sized and larger objects in the Kuiper Belt glowing in the infrared, a sign that was said to represent a Dyson Sphere type civilisation.
Either these are natural objects such as Brown Dwarf stars, or potential alien civilisations whom don’t care whether they are detected in the infrared or not.
And that’s disturbing.
From Centauri Dreams:
The assumptions we bring to interstellar flight shape the futures we can imagine. It’s useful, then, to question those assumptions at every turn, particularly the one that says the reason we will go to the stars is to find other planets like the Earth. The thought is natural enough, and it’s built into the exoplanet enterprise, for the one thing we get excited about more than any other is the prospect of finding small, rocky worlds at about Earth’s distance from a Sun-like star. This is what Kepler is all about. From an astrobiological perspective, this focus makes sense, as we want to know whether there is other life — particularly intelligent life — in the universe.
But interstellar expansion may not involve terrestrial-class worlds at all, though they would still remain the subject of intense study. Let’s assume for a moment that a future human civilization expands to the stars in worldships that take hundreds or even thousands of years to reach their destination. The occupants of these enormous vessels might travel in a tightly packed urban environment or perhaps in a much more ‘rural’ setting with Earth-like amenities. Many of them would live out their lives in transit, without the ability to be there at journey’s end. We can only speculate what kind of social structures might emerge around the ultimate mission imperative.
Moving Beyond a Planetary Surface
Humans who have grown up in a place that has effectively become their world are going to find its norms prevail, and the idea of living on a planetary surface may hold little interest. Isaac Asimov once wrote about what he called ‘planetary chauvinism,’ which falls back on something Eric M. Jones wrote back in the 1980s. Jones believed that people traveling to another star will be far more intent on mining asteroids and the moons of planets to help them build new habitats for their own expanding population. Stephen Ashworth, a familiar figure on Centauri Dreams, writes about what he calls ‘astro-civilizations,’ space-based cultures that focus on the material and energy resources of whatever system they are in rather than planets.
Ashworth’s twin essays appear in a 2012 issue of the Journal of the British Interplanetary Society (citation below) that grew out of a worldship symposium held in 2011 at BIS headquarters in London. The entire issue is a wonderful contribution to the growing body of research on worldships and their uses. Ashworth points out that a planetary civilization like our own thinks in terms of planetary resources and, when looking toward interstellar options, naturally assumes the primary goal will be to locate new ‘Earths.’ A corollary is the assumption of rapid transport that mirrors the kind of missions used to explore our own Solar System.
Image: A worldship kilometers in length as envisioned by space artist Adrian Mann.
An astro-civilization is built on different premises, and evolves naturally enough from the space efforts of its forebears. Let me quote Ashworth on this:
“A space-based or astro-civilisation…is based on technologies which are an extension of those required on planetary surfaces, most importantly the design of structures which provide artificial gravity by rotation, and the ability to mine and process raw materials in microgravity conditions. In fact a hierarchical progression of technology development can be traced, in which each new departure depends upon all the previous ones, which leads ultimately to an astro-civilisation.
The technology development Ashworth is talking about is a natural extension of planetary methods, moving through agriculture and industrialization into a focus on the recovery of materials that have not been concentrated on a planetary surface, and on human adaptation not only to lower levels of gravity but to life in pressurized structures beginning with outposts on the Moon, Mars and out into the system. Assume sufficient expertise with microgravity environments — and this will come in due course — and the human reliance upon 1 g, and for that matter upon planetary surfaces, begins to diminish. Power sources move away from fossil fuels and gravitate toward nuclear and solar power sources usable anywhere in the galaxy.
Agriculture likewise moves from industrialized methods on planetary surfaces to hydroponic agriculture in artificial environments. Ashworth sees this as a progression taking our adaptable species from the African Savannah to the land surface of the entire Earth and on to the planets, from which we begin, as we master the wide range of new habitats becoming available, to adapt to living in space itself. He sees a continuation in the increase of population densities that took us from nomadic life to villages to cities, finally being extended into a fully urbanized existence that will flourish inside large space colonies and, eventually, worldships.
An interstellar worldship is, after all, a simple extension from a colony world that remains in orbit around our own star. That colony world, within which people can sustain their lives over generations, is itself an outgrowth of earlier technologies like the Space Station, where residence is temporary but within which new skills for adapting to space are gradually learned. Where I might disagree with Ashworth is on a point he himself raises, that the kind of habitats Gerard O’Neill envisioned didn’t assume high population densities at all, but rather an abundance of energy and resources that would make life far more comfortable than on a planet.
This reminds me of an old Analog article I read back in the 1970s by Larry Niven titled “Bigger Than Worlds” in which Niven gave several examples of structures that evolved into massive structures from interstellar vessels to Ringworlds and Dyson Sphere, all of which were safer than natural planets.
Of course this goes by the assumption if human goes by the “expansion” route, or the “evo devo” route proposed by Jon Smart.
(STARpod.us) — Imagine this, then pretend it isn’t real.
Professor Stephen Hawking was right, contact with an extraterrestrial alien civilization might be the end of us — but he was wrong about one thing: it is too late to avoid contact with ultra-intelligent extraterrestrial aliens.
They are here, now, and living with you, perhaps within you, in your home.
And their actions are utterly invisible.
Worse still, every human thought, every human response to this invisible terror is already known and is shared across an intergalactic telepathic mind-to-mind based Internet.
The above may sound like a science fiction tale, however the reality may be worse than our most feared imaginings.
To enter into this “Twilight Zone” of darkness we simply accept that the brief history of human scientific and technological evolution points to an ever-greater penetration of the human mind — and the probability, given the unfathomable vastness of eternity currently predicted by our best theories of the universe and beyond, of intelligent minds beyond our own.
Our deepest, inner thoughts and experiences are going to be turned inside out upon the world.
We enter this virtual reality with an understanding that an encounter with alien intelligence beyond our own is something we may not even recognize, if and when it happens.
And according to sources, some who have held high positions within the U.S. government, close encounters have already taken place.
It is this unseen, largely unheard and secret presence that haunts us like a secret society from the great beyond. Probing our actions — even before they are taken — the vast and disturbingly alien mind behind this unstoppable terror of invisible things surrounds us, watching and waiting, like an invisible guardian in a cosmic conspiracy written eons before our time.
The cover story for contact with this deeply disturbing intelligence was written in Hollywood: extraterrestrial biological entities arrived on Earth in flying saucers and maybe they even crashed a disk or two, which were later recovered by the government.
It is this wrap-over story that has been spread by a handful of former CIA-types including the recent revelation by Chase Brandon. According to Brandon, bodies and wreckage (presumably of an extraterrestrial alien origin) were indeed recovered in Roswell, New Mexico. Others have hinted of some deeply buried truth underlying the saucer tales, based upon hearsay from their more senior colleagues in intelligence. And this, so we are told, goes all the way to the top, coming from at least a handful of former CIA Directors.
But is there really any truth in the tales? At a minimum, we should begin our exploration of the unstoppable terror of invisible things with a brief examination of down-to-earth technologies from human sources. We will, for the time being, ignore that other Hollywood-inspired meme claiming the most advanced human technologies of the 21st century owe their existence to reverse engineered extraterrestrial technology.
There are other stories of possible relevance, tales of invisible things that sometimes show their face in brief and mysterious ways. They sometimes seem to speak to select groups of human beings, in particular scientific types, using a form of direct mind-to-mind communication.
Mental radio has been an essential element of the pop culture for decades, and once again appears to be just another meme invented in the fantasy of a Hollywood writer’s imagination. The situation is further complicated by the countless number of persons who have self-experimented on the core physical structure of the human mind — the brain — by ingesting a wide variety of chemical substances known to create hallucinatory effects.
Invisible things do not always remain visible: there are other stories and sometimes grainy and poorly photographed images of manifestations of unusual phenomena popping in and out of our consensus reality. Other highly questionable reports include observations of ordinary material objects moving under the force of an unseen source. Several persons I know have related to me stories of so-called psychokinetic motion, including one person who told me of a misadventure involving knives that were picked up off of a table and flung with extreme force into the wall. In this particular story, it was reported that the environment changed mysteriously prior to the psychokinetic event, and even space and time seemed distorted in some inexplicable manner.
Psychokinesis was once a concern for American intelligence agencies and their political handlers in Congress (and this is confirmed within the declassified government record). Once upon a time they even feared psychokinetic hacking of America’s missile arsenal launch codes.
Invisibility is no longer bound to the imaginative world of sorcerer Harry Potter. As physicists look deeper into the nature of quantum reality they are gradually realizing new and clever ways around what was once assumed to be insurmountable obstacles. The late Arthur C. Clarke, author of “2001: A Space Odyssey” is often referenced for having said any sufficiently advanced technology appears (on the surface to those who do not understand it) to be magic.
Cracking through the barriers of human ignorance and human fantasy does not come easily. But if we are indeed facing an unstoppable terror of invisible things — real, physical forces under intelligent guidance — then we need to prepare a response.
We are challenged in this effort by the anthropocentric nature of the human mind: Is is really possible to envision truly alien sources and methods? Or are we confined to describing the extraterrestrial alien droning of America?
Bekkum makes many valid points about possible alien interference with we human beings on Earth; the most important point is the immaterial way the interference would take place. No flying saucers, triangles or spheres need apply.
Remote control of human beings, i.e., possession, ( or avatars ) via of “mental telepathy” for lack of a better term, would be preferable to outright invasion and destroying turf. Especially if proxy colonization or species manipulation is part and parcel of the alien’s overall strategies.
Habitability is the measure of highest value in planet-hunting. But should it be?
Kepler and the other planet-finding missions have begun to bear fruit. We now know that most stars have planets, and that a surprising percentage will have Earth-sized worlds in their habitable zone–the region where things are not too hot and not too cold, where life can develop. Astronomers are justly fascinated by this region and what they can find there. We have the opportunity, in our lifetimes, to learn whether life exists outside our own solar system, and maybe even find out how common it is.
We have another opportunity, too–one less talked-about by astronomers but a common conversation among science fiction writers. For the first time in history, we may be able to identify worlds we could move to and live on.
As we think about this second possibility, it’s important to bear in mind that habitability and colonizability are not the same thing. Nobody seems to be doing this; I can’t find any term but habitability used to describe the exoplanets we’re finding. Whether a planet is habitable according to the current definition of the term has nothing to do with whether humans could settle there. So, the term applies to places that are vitally important for study; but it doesn’t necessarily apply to places we might want to go.Whether a planet is habitable according to the current definition of the term has nothing to do with whether humans could settle there.
To see the difference between habitability and colonizability, we can look at two very different planets: Gliese 581g and Alpha Centauri Bb. Neither of these is confirmed to exist, but we have enough data to be able to say a little about what they’re like if they do. Gliese 581g is a super-earth orbiting in the middle of its star’s habitable zone. This means liquid water could well form on its surface, which makes it a habitable world according to the current definition.
Centauri Bb, on the other hand, orbits very close to its star, and its surface temperature is likely high enough to render one half of it (it’s tidally locked to its sun, like our moon is to Earth) a magma sea. Alpha Centauri Bb is most definitely not habitable.
So Gliese 581g is habitable and Centauri Bb is not; but does this mean that 581g is more colonizable than Bb? Actually, no.
Because 581g is a super-earth, the gravity on its surface is going to be greater than Earth’s. Estimates vary, but the upper end of the range puts it at 1.7g. If you weigh 150 lbs on Earth, you’d weigh 255 lbs on 581g. This is with your current musculature; convert all your body fat to muscle and you might just be able to get around without having to use leg braces or a wheelchair. However, your cardiovascular system is going to be under a permanent strain on this world–and there’s no way to engineer your habitat to comfortably compensate.
On the other hand, Centauri Bb is about the same size as Earth. Its surface gravity is likely to be around the same. Since it’s tidally locked, half of its surface is indeed a lava hell–but the other hemisphere will be cooler, and potentially much cooler. I wouldn’t bet there’s any breathable atmosphere or open water there, but as a place to build sealed domes to live in, it’s not off the table.
Also consider that it’s easier to get stuff onto and off of the surface of Bb than the surface of a high-gravity super-earth. Add to that the very thick atmosphere that 581g is likely to have, and human subsistence on 581g–even if it’s a paradise for local life–is looking more and more awkward.
Doubtless 581g is a better candidate for life; but to me, Centauri Bb looks more colonizable.
A definition of colonizability
We’ve got a fairly good definition of what makes a planet habitable: stable temperatures suitable for the formation of liquid water. Is it possible to develop an equally satisfying (or more satisfying) definition of colonizability for a planet?
Yes–and here it is. Firstly, a colonizable world has to have an accessible surface. A super-earth with an incredibly thick atmosphere and a surface gravity of 3 or 4 gees just isn’t colonizable, however much life there may be on it.
Secondly, and more subtly, the right elements have to be accessible on the planet for it to be colonizable. This seems a bit puzzling at first, but what if Centauri Bb is the only planet in the Centauri system, and it has only trace elements of Nitrogen in its composition? It’s not going to matter how abundant everything else is. A planet like this–a star system like this–cannot support a colony of earthly life forms. Nitrogen is a critical component of biological life, at least our flavour of it.
In an article entitled “The Age of Substitutibility”, published in Science in 1978, H.E. Goeller and A.M. Weinberg proposed an artificial mineral they called Demandite. It comes in two forms. A molecule of industrial demandite would contain all the elements necessary for industrial manufacturing and construction, in the proportions that you’d get if you took, say, an average city and ground it up into a fine pulp. There’re about 20 elements in industrial demandite including carbon, iron, sodium, chlorine etc. Biological demandite, on the other hand, is made up almost entirely of just six elements: hydrogen, oxygen, carbon, nitrogen, phosphorus and sulfur. (If you ground up an entire ecosystem and looked at the proportions of these elements making it up, you could in fact find an existing molecule that has exactly the same proportions. It’s called cellulose.)
Thirdly, there must be a manageable flow of energy at the surface. The place can be hot or cold, but it has to be possible for us to move heat around. You can’t really do that at the surface of Venus, for instance; it’s 800 degrees everywhere on the ground so your air conditioning spends an insane amount of energy just overcoming this thermal inertia. Access to a gradient of temperature or energy is what makes physical work possible.
Obviously things like surface pressure, stellar intensity, distance from Earth etc. play big parts, but these are the main three factors that I can see. It should be instantly obvious that they have almost nothing to do with how far the planet is from its primary. There is no ‘colonizable zone’ similar to a ‘habitable zone’ around any given star. The judgment has to be made on a world by world basis.
Note that by this definition, Mars is marginally colonizable. Why? Not because of its temperature or low air pressure, but because it’s very low in Nitrogen, at least at the surface. The combination of Mars and Ceres may make a colonizable unit, if Ceres has a good supply of Nitrogen in its makeup–and this idea of combo environments being colonizable complicates the picture. We’re unlikely to be able to detect an object the size of Ceres around Alpha Centauri, so long-distance elimination of a system as a candidate for colonizability is going to be difficult. Conversely, if we can detect the presence of all the elements necessary for life and industry on a roughly Earth-sized planet, regardless of whether it’s in its star’s habitable zone, we may have a candidate for colonizability.
The colonizability of an accessible planet with a good temperature gradient can be rated according to how well its composition matches the compositions of industrial and biological demandite. We can get very precise with this scale, and we probably should. It, and not habitability, is the true measure of which worlds we might wish to visit.
To sum up, I’m proposing that we add a second measure to the existing scale of habitability when studying exoplanets. The habitability of a planet actually says nothing about how attractive it might be for us to visit. Colonizability is the missing metric for judging the value of planets around other stars.
This raises the ethical question of at which point do we as a race change the environment of an alien world’s biology in order to suit our needs?
Do we engage in biological genicide to seed a planet with Earth-life, or do we adapt ourselves to suit the exoplanet’s environment?
Or do we move on to another planet that is more “colonizable” as Schroeder suggests and totally build a habitat from scratch?
Hat tip to Centauri Dreams.
From Centauri Dreams:
What happens to us if our SETI efforts pay off? Numerous scenarios come to mind, all of them speculative, but the range of responses shown in Carl Sagan’s Contact may be something like the real outcome, with people of all descriptions reading into a distant message whatever they want to hear. Robert Lightfoot (South Georgia State College) decided to look at contact scenarios we know something more about, those that actually happened here on Earth. His presentation in Huntsville bore the title “Sorry, We Didn’t Mean to Break Your Culture.”
Known as ‘Sam’ to his friends, Lightfoot is a big, friendly man with an anthropologist’s eye for human nature. His talk made it clear that if we’re going to plan for a possible SETI reception, we should look at what happens when widely separated groups come into contact. Cultural diffusion can happen in two ways, the first being prompted by the exchange of material objects. In the SETI case, however, the non-material diffusion of ideas is the most likely outcome. Lightfoot refers to ‘objects of cultural destruction’ in both categories, noting the distorting effect these can have on a society as unexpected effects invariably appear.
Consider the introduction of Spam to the islands of the Pacific as a result of World War II. The level of obesity, cancer and diabetes soared as cultures that had relied largely on hunting, farming and fishing found themselves in the way of newfound supplies. Visitors to some of these islands still note with curiosity that Spam can be found on the menus of many restaurants. Today more than half of all Pacific islanders are obese, and one in four has diabetes. On the island nation of Tonga, fully 69 percent of the population is considered obese.
Lightfoot mentioned Tonga in his talk, but I drew the above figures from the World Diabetes Foundation. Can we relate the continuing health problems of the region to Spam? Surely it was one of the triggers, but we can also add that the large-scale industrialization of these islands didn’t begin until the 1970s. Imported food and the conversion of farmland to mining and other industries (Nauru is the classic example, with its land area almost entirely devoted to phosphate mining) meant a change in lifestyle that was sudden and has had enormous health consequences.
Objects of cultural destruction (OCDs) show their devastating effects around the globe. The Sami peoples of Finland had to deal with the introduction of snowmobiles, which you would have thought a blessing for these reindeer herders. But the result was the ability to collect far larger herds than ever before, which in turn has resulted in serious problems of over-grazing. Or consider nutmeg, once thought in Europe to be a cure for the plague, causing its value to soar higher than gold. Also considered an aphrodisiac, nutmeg led to violence against native growers in what is today Indonesia and played a role in the creation of the East India Company.
But because SETI’s effects are most likely going to be non-material, Lightfoot homed in on precedents like the ‘cargo cults’ of the Pacific that sprang up as some islanders tried to imitate what they had seen Westerners do, creating radios out of wood, building ‘runways’ and calling for supplies. In South Africa, a misunderstanding of missionary religious teachings led the Xhosa people to kill their cattle, even though their society was based on herding these animals. Waiting for a miracle after the killings, a hundred thousand people began to starve. Said Lightfoot:
Think about contact with an extraterrestrial civilization in this light. There will be new ideas galore, even the possibility of new objects — plants, animals, valuable jewels. Any or all of these could be destabilizing to our culture. And just as they may destabilize us, we may contaminate them.
I think the most powerful message of Lightfoot’s talk was that this kind of destabilization can come where you would least expect it, and have irrevocable results. Tobacco, once used as a part of ritual ceremonies in the cultures where it grew, has become an object of cultural and medical destruction in our far more affluent society. Even something as innocuous as a tulip once became the object of economic speculation so intense that it created an economic bubble in 17th Century Holland and an ensuing economic panic.
What to do? Lightfoot told the crowd to search history for the lessons it contains about cultures meeting for the first time. We need to see when and why things went wrong in hopes of avoiding similar situations. If contact with an extraterrestrial culture someday comes, we’ll need a multidisciplinary approach to identify the areas where trouble is most likely to occur. A successful SETI reception could be the beginning of a philosophical and scientific revolution, or it could be the herald of cultural decline as we try to re-position our thinking about the cosmos.
I don’t think the radio searches of SETI will produce anything; there’s a better chance that UFOs are ET spacecraft and eventually black ops corporations will reveal that they’ve been back engineering their hardware for years.
That being said, on the off chance that ET contact does happen, in any form, cultural cross contamination is bound to happen. Whether some cargo cults will form because of contact is moot, because in my opinion, that’s how the world’s religions were formed in the past.
From The Daily Galaxy:
The species that you and all other living human beings on this planet belong to is Homo sapiens. During a time of dramatic climate change 200,000 years ago,Homo sapiens (modern humans) evolved in Africa. Is the human species entering another evolutionary inflection point?
Paul Davies, a British-born theoretical physicist, cosmologist, astrobiologist and Director of the Beyond Center for Fundamental Concepts in Science and Co-Director of the Cosmology Initiative at Arizona State University, says in his new book The Eerie Silence that any aliens exploring the universe will be AI-empowered machines. Not only are machines better able to endure extended exposure to the conditions of space, but they have the potential to develop intelligence far beyond the capacity of the human brain.”I think it very likely – in fact inevitable – that biological intelligence is only a transitory phenomenon, a fleeting phase in the evolution of the universe,” Davies writes. “If we ever encounter extraterrestrial intelligence, I believe it is overwhelmingly likely to be post-biological in nature.”Before the year 2020, scientists are expected to launch intelligent space robots that will venture out to explore the universe for us.
“Robotic exploration probably will always be the trail blazer for human exploration of far space,” says Wolfgang Fink, physicist and researcher at Caltech. “We haven’t yet landed a human being on Mars but we have a robot there now. In that sense, it’s much easier to send a robotic explorer. When you can take the human out of the loop, that is becoming very exciting.”
As the growing global population continues to increase the burden on the Earth’s natural resources, senior curator at the Smithsonian National Air and Space Museum, Roger Launius, thinks that we’ll have to alter human biology to prepare to colonize space.
In the September issue of Endeavour, Launius takes a look at the historical debate surrounding human colonization of the solar system. Experiments have shown that certain life forms can survive in space. Recently, British scientists found that bacteria living on rocks taken from Britain’s Beer village were able to survive 553 days in space, on the exterior of the International Space Station (ISS). The microbes returned to Earth alive, proving they could withstand the harsh environment.
Humans, on the other hand, are unable to survive beyond about a minute and a half in space without significant technological assistance. Other than some quick trips to the moon and the ISS, astronauts haven’t spent too much time too far away from Earth. Scientists don’t know enough yet about the dangers of long-distance space travel on human biological systems. A one-way trip to Mars, for example, would take approximately six months. That means astronauts will be in deep space for more than a year with potentially life-threatening consequences.
Launius, who calls himself a cyborg for using medical equipment to enhance his own life, says the difficult question is knowing where to draw the line in transforming human biological systems to adapt to space. Credit: NASA/Brittany Green
“If it’s about exploration, we’re doing that very effectively with robots,” Launius said. “If it’s about humans going somewhere, then I think the only purpose for it is to get off this planet and become a multi-planetary species.”
Stephen Hawking agrees: “I believe that the long-term future of the human race must be in space,” Hawking told the Big Think website in August. “It will be difficult enough to avoid disaster on planet Earth in the next hundred years, let alone the next thousand, or million. The human race shouldn’t have all its eggs in one basket, or on one planet.”
If humans are to colonize other planets, Launius said it could well require the “next state of human evolution” to create a separate human presence where families will live and die on that planet. In other words, it wouldn’t really be Homo sapien sapiens that would be living in the colonies, it could be cyborgs—a living organism with a mixture of organic and electromechanical parts—or in simpler terms, part human, part machine.
“There are cyborgs walking about us,” Launius said. “There are individuals who have been technologically enhanced with things such as pacemakers and cochlea ear implants that allow those people to have fuller lives. I would not be alive without technological advances.”
The possibility of using cyborgs for space travel has been the subject of research for at least half a century. A seminal article published in 1960 by Manfred Clynes and Nathan Kline titled “Cyborgs and Space” changed the debate, saying that there was a better alternative to recreating the Earth’s environment in space, the predominant thinking during that time. The two scientists compared that approach to “a fish taking a small quantity of water along with him to live on land.” They felt that humans should be willing to partially adapt to the environment to which they would be traveling.
“Altering man’s bodily functions to meet the requirements of extraterrestrial environments would be more logical than providing an earthly environment for him in space,” Clynes and Kline wrote.
“It does raise profound ethical, moral and perhaps even religious questions that haven’t been seriously addressed,” Launius said. “We have a ways to go before that happens.”
Some experts such as medical ethicist Grant Gillett believe that the danger is that we might end up producing a psychopath because we don’t quite understand the nature of cyborgs.
NASA, writes Lauris, still isn’t focusing much research on how to improve human biological systems for space exploration. Instead, its Human Research Program is focused on risk reduction: risks of fatigue, inadequate nutrition, health problems and radiation. While financial and ethical concerns may have held back cyborg research, Launius believes that society may have to engage in the cyborg debate again when space programs get closer to launching long-term deep space exploration missions.
“If our objective is to become space-faring people, it’s probably going to force you to reconsider how to reengineer humans,’ Launius said.