Cosmic Loneliness and Interstellar Travel

by Paul Gilster on December 6, 2013

Nick Nielsen’s latest invokes the thinking of Carl Sagan, who explored the possibilities of interstellar ramjets traveling at close to the speed of light in the 1960’s. What would the consequences be for the civilization that developed such technologies, and how would such starships affect their thinking about communicating with other intelligent species? Sagan’s speculations took humans not just to the galactic core but to M31, journeys made possible within a human lifetime by time dilation. Nielsen, an author and contributing analyst with strategic consulting firm Wikistrat, ponders how capabilities like that would change our views of culture and identity. Fast forward to the stars, after all, means you can’t go home again.

by Nick Nielsen

Nick-Nielsen

In my previous Centauri Dreams post, I discussed some of the possible explanations of what Paul Davies has called the “eerie silence” – the fact that we hear no signs of alien civilizations when we listen for them – in connection with existential risk. Could the eerie silence be a sign that older civilizations than ours have been risk averse to the point of plunging the galaxy into silence, perhaps even silencing others (making use of the Rezabek maneuver)? It is a question worth considering.

For one answer is that we are alone, or very nearly alone, in our galaxy, and probably also in our local cluster of galaxies, and perhaps also alone even in our local supercluster of galaxies. I think this may be the case partly due to the eerie silence when we listen, but also due to what may be called our cosmic loneliness. Not only are our efforts to listen for other intelligences greeted with silence, but also the attempts to demonstrate any alien visitation of our planet or our solar system have turned up nothing. When we listen, we hear only silence, and when we look, we find nothing.

The question, “Are we alone?” has come to take on a scientific poignancy that few other questions hold for us, and we ask this question because of our cosmic loneliness. We are beginning to understand the Copernican revolution not only on an intellectual level, but also on a visceral level, and for many who experience this visceral understanding the result is what psychoanalyst Viktor Frankl called the existential vacuum; the whole cosmos now appears as an existential vacuum devoid of meaning, and that is why we ask, “Are we alone?” We ask the question out of need.

nielsen_image1

Image credit: TM-1970, Russia (via Dark Roasted Blend).

While talk of alien visitation is usually dominated by discussions of UFOs (and merely by mentioning the theme I risk being dismissed as a crackpot), due to the delay involved in EM spectrum communications, it is at least arguable that communication is less likely than travel and visitation. That being said, I do not find any of the claimed accounts of extraterrestrial visitation to be credible, and I will not discuss them, but I will try to show why visitation is more likely than communication via electromagnetic means.

An organic life form having established an industrial-technological civilization on its homeworld – rational beings that we might think of as peer species – would, like us, have risen from biological deep time, possessing frail and fragile bodies as we do, subject to aging and deterioration. An advanced technological civilization could greatly extend the lives of organic beings, but how long such lives could be extended (without being fully transformed into non-organic beings, i.e., without becoming post-biological) is unknown at present.

For EM spectrum communications across galactic distances, even the most long-lived organic being would be limited in communications to only a small portion of its home galaxy. If civilizations are a rarity within the galaxy, the likelihood of living long enough to engage in even a single exchange is quite low. In fact, we can precisely map the possible sphere of communication of a being with a finite life span within our galaxy (or any given galaxy) based on the longevity of that life form. Even an extraordinarily long-lived and patient ETI would not wish to wait thousands of years between messages, especially in view of the quickening pace of civilization that comes about with the advent of telecommunications.

It could be argued that non-organic life forms take up where organic life forms leave off, and for machines to take over our civilization would mean that length of life becomes much less relevant, but the relative merits and desirability of mechanistic vs. organic bearers of industrial-technological civilization (not to speak of being bearers of consciousness) is a point that needs to be argued separately, so I will not enter into this at present. But whether ETI is biological or post-biological, no advanced intellect is going to send out a signal and wait a thousand years for a response, since in that same thousand year period it would be possible to invent the technologies that would allow for travel to the same object of your communication in a few years’ time (i.e, a few years in terms of elapsed shipboard time).

Our perfect ETI match as a peer civilization in the Milky Way will have already realized that electromagnetic communications mean waiting too long to talk to planetary systems that can be visited directly. If they are a hundred years ahead of us, they may already have started out and may find us soon. If they are a hundred years behind us, they will not yet even have the science to conceive of these possibilities as realizable technological aims. But what is the likelihood, in the universe in which intelligent life is rare (and we know by now that there are no “super-civilizations” nearby us in cosmic terms – cf. my Searching the Sky), that in all the vast space and time of the universe, a peer civilization should arise within a hundred years’ development of our own civilization? Not very likely.

The further we push out the temporal parameters of this observation, the more likely there is another civilization within these temporal parameters, but the further such a civilization is from being a peer civilization. Take a species a thousand years behind us or a thousand years ahead of us: the former cannot form a conception of the universe now known to observational cosmology; the latter will have technological abilities so far beyond ours (having had an industrial-technological civilization that has been in existence five times longer than ours) that we would not be in any sense their peer. And they would have already visited us. If we set the parameters of temporal radius from the present at ten thousand years, or a hundred thousand years, we are much more likely to find life on other worlds, but the further from our present level of development, the less likely any life found would be recognizable as a peer civilization.

How would we visit other worlds directly? With the breakthrough technology of a 1G starship (i.e., a starship than can accelerate or decelerate at a constant of one gravity) [2], all of the waiting to discover the universe and what lies beyond virtually disappears for those willing to make the journey. And while I have called this 1G starship a “breakthrough technology,” it is not likely to happen all at once in a breakthrough, but will probably take decades (if not centuries) of development. Our first interstellar probes, Voyager 1 and Voyager 2, are already headed to the stars [3]. It would take tens of thousands of years for the Voyager probes to arrive at another solar system, should they survive so long. Incremental improvements even in known propulsion technologies will yield gradually more efficient and effective interstellar travel (and will not require any violations of the laws of physics). While we don’t yet have full breakeven in inertial confinement fusion [4], we can in fact achieve inertial confinement fusion at an energy loss, meaning that an inertial confinement fusion starship drive is nearly within the capability of present technology. All of this leaves aside the possibility of breakthrough technologies that would be game-changers (such as the Alcubierre drive).

If we assume that a peer species would emerge from an Earth twin, we can assume that such a peer species would be subject to roughly similar gravitational limitations, so that an ETI 1G starship would be something similar in terms of velocity. Human beings or a peer ETI species, while unable to engage in any but the most limited EM spectrum communications over galactic distances, would find the galaxy opened up to them by a 1G starship, able to explore the farthest reaches of the universe within the ordinary biological lifetime of intelligent life forms even as we know such life forms today (i.e., ourselves), limited to a mere three score and ten, or maybe a bit more.

I have mentioned inertial confinement fusion above as a possible starship propulsion system, but this example is not necessary to my argument. If there existed only a single propulsion proposal for interstellar travel, and all our hopes for such travel rested on an unknown science and an unknown technology, we would have good reason to be skeptical that interstellar travel would ever be possible under any circumstances. This, however, is not the case. There are a wide variety of potential interstellar propulsion technologies, including inertial confinement fusion, matter-antimatter, quantum vacuum thrusters, and other even more exotic ideas. As long as industrial-technological civilization continues its development, some advanced propulsion idea is likely to prove successful, if only marginally so, but marginally will be enough for the first pioneers who are willing to sacrifice all for the chance at a new world.

It is humbling that we know so little about these technologies and the science that underlies them that we are not today in a position to say which among these might prove to be robust and durable drives for a starship, but the very fact that we know so little implies that we have much to learn and we cannot yet exclude any of these exotic starship drive possibilities, much less dismiss them as impossible. While no one has yet produced a proof of concept of any of these proposed forms of propulsion, it is also the case that no one has yet falsified the science upon which they are based.

Even the most successful of the drives mentioned above (with the exception of the Alcubierre drive) will involve time dilation as a condition of interstellar travel. There has been a tendency to view time dilation as a cosmic “fun spoiler” that prevents us seeing the universe on our own terms, since the elapsed time on one’s home world means that no one can return to the world that they left. We need to get beyond this limiting idea and come to see time dilation as a resource that will allow us to travel throughout the galaxy. It is true that time dilation is a limitation, but it is also an opportunity. As Carl Sagan noted:

“Relativity does set limits on what humans can ultimately do. But the universe is not required to be in perfect harmony with human ambition. Special relativity removes from our grasp one way of reaching the stars, the ship that can go faster than light. Tantalizingly, it suggests another and quite unexpected method.” [5]

Human ambition, as Sagan suggests, wants interstellar travel without the price exacted by time dilation, but the universe is not going to accommodate this particular ambition. We have had to reconcile ourselves with the fact that historical transmission is a unidirectional process. We can read Shakespeare, but we cannot talk to Shakespeare. Shakespeare’s contemporary Queen Elizabeth could make it known that she wanted to see Falstaff in love, and “The Merry Wives of Windsor” resulted, but we cannot approach the Bard to write the perfect comedy of manners in which smart phones and text messages figure in the plot.

Just so, we are all unidirectional time travelers, and the eventual development of travel at relativistic velocities will not give us the ability to travel backward in time, nor will it allow us to travel to the stars without giving thought to the inertial frame of reference of our homeworld, but it will give us more alternatives for going forward in time. We will have the opportunity to choose between an inertial framework at rest (presumably relative to our homeworld), and some accelerated inertial framework in which time passes more slowly, allowing us to travel farther and, incidentally, to see more of the universe. Even if we can never go back, we can always go forward. Relativistic interstellar travel will mean that we have a choice as to how rapidly we move forward in time. The possibility of always going farther forward in time has consequences for existential risk mitigation that I will discuss in my next Centauri Dreams post.

Notes

[1] Cf. Viktor Frankl, Man’s Search for Meaning

[2] Carl Sagan discussed the 1G starship in his Cosmos, Chapter VIII, “Travels in Space and Time”; I quote from this same chapter below.

[3] As of this writing, Voyager 1 has passed into interstellar space, while Voyager 2 has not yet emerged from the heliosheath and into interstellar space.

[4] A near breakeven in inertial confinement fusion was recently achieved, in which produced more energy that was absorbed by the fuel for the reaction, but this is not the same as producing as much energy from the fusion reaction as was pumped into the lasers making the reaction happen. (Cf. Nuclear fusion milestone passed at US lab.)

[5] Carl Sagan, Cosmos, Chapter VIII, “Travels in Space and Time” (cf. note [2] above)

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{ 96 comments… read them below or add one }

Tom December 8, 2013 at 23:30

‘The Sphere of Temporal limit’ is a fascinating term; however there is plenty of scanning of the Universe for conventional purposes. Between dark matter & space ripping, the cosmologists & astrophysicists don’t get much press for discovering neutron stars or new comets. Can pulsars be detected in other galaxies? They make good time keepers & yardsticks!

We have plenty of places to explore for manned expeditions inside our own solar system; and good reasons to do this… even colonizing Mars.
50 year one-way trips to Proxima Centauri or Sirius would be great; but this would be a vast investment compared to building arrays or launching telescopes & various detectors.

As for Life in the Universe, since we scanned down a drop of ‘dirty pond water’ back in the 1600s, then Darwin & Mendel and finding active prebiotic molecular clouds in interstellar space… biology is greater than zero at the cosmic level.

Will humankind find intelligence out there? I think even being successful with detection… it will be more like finding a cave painting in the wilderness.

Sean M. Brooks December 9, 2013 at 0:46

Very interesting essay by Mr. Nielsen. Some of the ideas he discusses reminds me of what I’ve read in various of the works of Poul Anderson, both non fiction and fiction. Here I have in mind IS THERE LIFE ON OTHER WORLDS? (1963) and his four HARVEST OF STARS books, plus GENESIS and STARFARERS.

I would like to know if any readers can recommend later works by other writers touching on the ideas Anderson discussed in IS THERE LIFE ON OTHER WORLDS? Including, for that matter, any commentary about this Anderson book.

Nick Nielsen December 9, 2013 at 6:36

@James Benford

The NIF news was indeed a moving-the-goalposts maneuver. As you point out, these are tight times for budgets, and they may have needed a headline. Both ICF and MCF have proved to be tough nuts to crack from an engineering standpoint, but to appeal once again to the distinction between physics problems and engineering problems (a distinction that I now see I must elucidate, which I will do in some future post), we have stars as the existence proof that fusion is possible. In other words, it is consistent with the known laws of physics; it remains for us to find a technological way to do what nature has already done. Fusion technology most definitely has not experienced exponential growth, but it is seeing very gradual progress.

RE: “You can get energy out from fusion reactions, which was done a long time ago. But to make a fusion rocket is far harder: energy out must exceed energy in, or the ship runs out of energy, shuts down.”

Agreed that it is much harder to make a fusion rocket. But suppose, just for the sake of argument, that a fusion rocket was incredibly effective, but we still hadn’t much improved our fusion breakeven statistics. It would be possible to install another power source on board a ship (say, durable and predictable fission technology) in order to power a fusion drive. Again, this would only make sense if a fusion drive were extraordinarily effective, more effective that simply constructing a fission drive. But it is possible in theory. And, as I attempted to show above, there are many possible technologies for starship drives; we are not relying solely on fusion.

Nick Nielsen December 9, 2013 at 6:45

@Heath Rezabek

Heath, thanks much for saying a few words about peer civilizations. This is an idea that deserves separate elucidation, and maybe we can write more about this.

While reading your remarks I realized that, up to a certain level, technological civilizations probably retain a high level of “backward compatibility.” Simply on the surface of the Earth, there are many peoples at many different levels of technological development. Given an advanced spacefaring civilization, distributed even more widely than civilization on the surface of Earth, we are also likely to see a a variety of levels of technology, some of them roughly compatible with less developed civilizations, and this broad experience of lifeways could be quite useful in terms of establishing some kind of rapport with an exocivilization, if only because xenologists and sociologists would have studied these societies and had some understanding of them.

Nick Nielsen December 9, 2013 at 6:52

@coacervate

I think you are much more likely to find this zeal among the Russians than the Chinese, but the Chinese economy is doing much better than the Russian economy, so it is difficult to Russian scientists to find the resources for research.

While we cannot rule out SETI success in the future (I have written previously about SETI as a gradual process of elimination: http://geopolicraticus.wordpress.com/2011/08/01/seti-as-a-process-of-elimination/), we can rule out nearby super-civilizations of the kind that might put out a powerful beacon. And now that we know from recent Kepler research that planets in habitable zones are relatively common, and there may be some within a few tens of light years from us, we can be confident that life and technological civilization don’t just spring up inevitably when you find a planet in the right spot.

Nick Nielsen December 9, 2013 at 6:58

@Tarmen

Yours is a very creative response to the Fermi paradox, and one worth developing further. Indeed, we can still carve out a niche in the kind of universe you describe, as the mammals had a little niche during the time of the dinosaurs. Just as climatological change and catastrophic events change the conditions of life on Earth, cosmological changes and catastrophes may similarly change the cosmological conditions of spacefaring civilizations, so that, under your scenario, we might yet inherent the territory of one of those old bears if is keels over, or if the species goes extinct.

ljk December 9, 2013 at 9:25

Wojciech J said on December 8, 2013 at 19:54:

“coacervate-the best bet now seem to be telescopic observations for first biospheres and then signs of technosignatures of advanced civilizations.
For many reasons, that were discussed here before, radio signals aren’t the best way to communicate or detect others. SETI is far too much focused on them.”

When radio was suggested as the best means of detecting ETI back in 1959, radio astronomy was a fairly new and exciting branch of the field. And while many astronomers paid lip service to aliens being both alien and much more advanced than us, they still ended up assuming they would be similar to us in many ways. This included how they might send messages across the galaxy.

Thus SETI has been focused on radio since 1960 (or 1924 if you want to count the efforts to listen for signals from Mars). Even Optical SETI was pushed to the side until 1998 due to this overfocus on radio. While radio is not a bad way to send messages from one star to another, it is not the only way and it is time that 21st century SETI folks started getting with the times.

Ironically, when Cocconi and Morrison wrote their famous paper in Nature in 1959, they initially considered detecting gamma rays from alien civilizations, not radio.

http://www.coseti.org/morris_0.htm

http://www.centauri-dreams.org/?p=4914

ljk December 9, 2013 at 9:50

coacervate said on December 8, 2013 at 6:28 (in quotes):

“I would ask that you post a “50 years of SETI” compendium so we can better understand this comprehensive body of work that leads so many to conclude…SILENCE! Not to be overly negative, but I don’t think you will find it. Ozma? WOW? Phoenix? Hat Creek? Baby steps. I don’t think we have made anything like a systematic survey for the detection of narrow band microwave or optical wavelength signals. ”

Here are some histories of SETI. You are correct indeed that most SETI searches have been sporadic at best, looking at a few fields of stars for a matter of hours or days. In a galaxy with 400 billion stars that is 10 billion years old? Absurd.

http://www.jb.man.ac.uk/distance/life/sample/seti/

http://history.nasa.gov/seti.html

Even the Ohio State SETI program, which lasted from 1973 to 1998 (when the university tore down the Big Ear radio telescope and gave the land over to a golf course and condos – now there is a sign of intelligence for you), was not operated 24/7: The famous Wow! Signal of 1977 was not discovered until well after it was printed out on a piece of computer output paper.

http://www.bigear.org/wowmenu.htm

http://www.centauri-dreams.org/?p=1412

The ATA SETI project has been suffering from lack of funds due in one part to the rotten economy and also to their focusing on building the radio telescope farm but not the need for upkeep et al. They have gotten some infusions of cash to keep going but how long will this last? Drake also said about a year or so ago that they had all this data but no money for sifting through it. This is 21st Century SETI?

http://www.nature.com/news/2011/110727/full/475442a.html

“One possible exception: SETIatHome, who report little but many hits. Considering the current disdain for science among USAmericans, I can’t see anything tangible in the works. I wonder if the Chinese zeal for knowledge and space science extends into SETI? Thus, my search continues “on this most unbright cinder”…not to be overly negative, mind you.”

So what has been happening with SETI@Home? How many people are still running it on their computers? Who is analyzing the data? Why aren’t other radio observatories doing this?

And there is another question I have asked here several times regarding the Chinese: Are they going to do SETI? METI? They are building a radio telescope that will be bigger than Arecibo.

http://news.discovery.com/space/astronomy/monster-chinese-telescope-the-next-et-hunter-110621.htm

All this is why I do not want to hear from anyone that too much money is being spent on SETI. If anything the real crime is that not enough funding and time has been given to SETI. These private efforts are suffering. It also makes me wonder if this is a reflection on how things might go if private industry funds our space program?

ljk December 9, 2013 at 9:59

One would hope that an advanced civilization would have eliminated light pollution. You and the authors are also assuming that aliens need to illuminate their cities like ours (if they also even build cities) and that these beings want to live on the surface of their worlds – or even live on Earthlike planets at all.

Again, aliens will be ALIEN. clearly Star Trek and its kind have long polluted our notions of ETI.

Wojciech J said on December 8, 2013 at 21:12:

“The luminosity of Earth from artificial lighting is 14 orders of magnitude less than the sun. This signal-to-noise ratio defeats such observation”

Advanced hypertelescopes would be able to take pictures of planets with resolution allowing imagining continents.
With that city lights are easily visible.

“City Lights Could Reveal E.T. Civilization
http://www.cfa.harvard.edu/news/2011-30
Cambridge, MA

swage December 9, 2013 at 11:09

The Fermi Paradox (the great/eerie silence) may very well be one of the biggest blunders ever devised.

There was a time when our people looked into the night sky, imagining how much planets in the solar system were habitable at a time. This is reflected in in old science fiction: Venusian jungles and Martian transport tubes.

The first serious blow to our, maybe a bit naive, but also confident perception of life in the cosmos came in the form of Special Relativity. The very stars were moved beyond our reach into the cosmic abyss of space and time.

The second blow came as we improved our technological capabilities to observe and send probes to explore our home star system. We learned that Earth alone was the sole habitable spot we could find.

The third blow came as we built gigantic detectors to listen to the chatter of the universe. We found nothing.

And as a result most of us turned away. We don’t want to see anymore. We don’t discuss such topics in public. Its weird. Better to spend the funds somewhere else. We can’t bear it. Even to think about the topic in public is stigmatized.

What we are dealing with here is a depression. A depression that has engulfed the most of the human race.

As the above article points out so fittingly, Special Relativity isn’t humanities cage. Once the rules are understood in full it works both ways. A ship traveling at relativistic speeds (not light speed but close to it) experiences time slower. This means it is possible to cross the galaxy in a human lifetime due the time dilatation effect. It isn’t prohibiting us from reaching the stars, on the contrary: its making such voyages possible in the first place.

Our probes are now telling us our closest neighbor planet had habitable conditions. The transport tubes were rivers. Not some toxic liquid ammonia cocktail. Water. Planets in the habitable zones of stars are now, based on our most recent observations, expected in the order of billions for this galaxy alone.

We wouldn’t be capable to pick up radio emissions that are comparable to what we emit ourselves in excess of a light year with our current equipment. We can’t pick up the equivalent of “I love Lucy”. To that we need equipment 200.000 orders of magnitude more efficient that what we use today, just to isolate the signal. Inverse square Law.

So, where are the star ships?

Also here Special Relativity is a key factor. Whilst time dilatation hastens the voyage for a star ship crew, it doesn’t do the same trick for external observers. These voyages can be estimated to take multitudes of millennia between even the closest stars. These events are relatively exceptional.

Also, i am not too sure the technological path of advanced civilizations – or our own, for that matter – necessarily results in the machines we’d imagine at this point.

As a higher mass demands more energy, the most efficient way leads in my opinion to miniaturization. That doesn’t necessarily harmonize with our idea of manned space flight, but it solves many problems. There is a reason why we employ more and more robotic messengers in our own fleet. Its much more feasible.

That being said, pushing the limits on miniaturization results in nanotechnology. And on a molecular level its really hard to tell technology apart from biology. At this level the border practically vanishes. All of it is molecular machinery. This not only means that the expected result would be more like biotechnology, it also raises the question if we are able to recognize such “technology”, which is the most feasible, as such.

Back in the old days where computer programs could be fit on a few floppy disks the concept of packing data into compressed archives was the usual method of transmitting data. The problem was that there were numerous packing programs and you often found that the person you wanted to deliver the data to lacked the program to unpack it. There was a simple solution of course and that was self-decompressing archive executables.

If we apply this concept to biotechnology, we circumvent a whole lot of perquisites the receiver has to match to access the data. It also lingers around a very long time, especially if the information duplicates itself on its own. This would be a far more feasible way of distributing information throughout space and time than radio signals.

We may be totally mislead. So do me a favor and snap out of this “great silence” depression. Every lead we have today suggests the contrary. Its very probable that it doesn’t even exist.

In about 8 years we will have for the first time to observe exoplanet atmospheres directly, the tools to make such observations in the first place.

Personally i think chances are very good that we will experience a rather big surprise. About time.

Alex Tolley December 9, 2013 at 13:01

“But to make a fusion rocket is far harder: energy out must exceed energy in, or the ship runs out of energy, shuts down”

I’m not sure it is harder. However, we can do it “today” by exploding h-bombs and riding the fragments. This would be the Orion concept, or the Dyson “sail” that was discussed some while ago. It certainly wouldn’t be very efficient, nor elegant, but it is a brute force use of fusion for propulsion that uses the rocket principle.

Paul W December 9, 2013 at 20:17

One of the better articles I have read here of late.

This guy really understands the silence problem. He doesn’t gloss over it.

To be alone in our entire supergroup of galaxies?? Even a skeptic like me is not ready to go there yet. That’s gloomy.

I appreciate the writer’s carefulness in not exceeding our capabilities and planning, for now, in accordance with them. But guys, it’s early in the game.
Don’t head for the exits.

“Relativity does set limits on what humans can ultimately do”. My hero, Carl conceded this point. But why would he do that?
If you had asked some stone age person about getting across a continent, they would have told you it would take decades. What? The stone age man, a deep thinker, missed jet travel?
But the laws of physics rule out FTL. Yes, they do, as far as Einstein could tell. Does anyone here think the laws of physics are completely known?

I think the Fermi Paradox is a very serious problem. I think the speed of light is a very serious limitation.
All we have to do today is keep putting one foot in front of the other foot.
If we just keep doing that, and don’t go backward….the galaxy is ours.

Eniac December 9, 2013 at 23:45

@Nick:

Relativity tells us why it is not possible for a starship to travel at the velocity of light. That is a physical impossibility. The laws of physics do not allow for this. However, the laws of physics do not specify anything about contingent circumstances about the interstellar medium.

You are correct, the existence of the interstellar medium is more of a fact than a law. However, that does not make it any less real. The laws of physics say that the ISM, assuming it is there (as we know it is), will keep you from reaching more than a fraction of c with any sort of material object without being incinerated quickly. Going at 0.8 c or so is akin to diving into the sun. Neither is likely to be possible within the known laws of physics, at least in the materials field. Yes, there are more rarefied regions of the galaxy than ours, but we could not really get there from here, in decent time.

Eniac December 10, 2013 at 0:06

Brett Bellmore:

I think a dirty plasma, maintained in front of the ship by magnetic fields, could be much hardier than any solid material. The real issue, IMO, is the need to carry fuel to overcome drag.

A plasma would have to be pretty dense to catch all or almost all of the oncoming gas. And all the magnets would have to be behind the plasma, making it difficult to imagine a way to contain it. Also, the plasma would leak into space and you cannot really afford to lose the material. The only hope is to deflect the gas with pure fields, but that is difficult with it being neutral and very fast.

Momentum loss (drag) is not a problem. It’s is miniscule compared to that of the absorbed energy. That is because energy goes with the square of velocity, momentum only linearly.

Philippe Ailleris December 10, 2013 at 3:13

Great article and just a request for clarification concerning the above statement: ”…but also the attempts to demonstrate any alien visitation of our planet or our solar system have turned up nothing. When we listen, we hear only silence, and when we look, we find nothing.”

I’m interested to know to which attempts to demonstrate any alien visitation of our planet the author refers to ? Can we honestly state we really have seriously tried ? I think that this is an interesting domain to explore.

ljk December 10, 2013 at 9:31

Paul W said on December 9, 2013 at 20:17:

“If we just keep doing that, and don’t go backward….the galaxy is ours.”

I wonder if others out there are thinking the exact same thing….

ljk December 10, 2013 at 10:35

Philippe Ailleris said on December 10, 2013 at 3:13:

“Great article and just a request for clarification concerning the above statement: ”…but also the attempts to demonstrate any alien visitation of our planet or our solar system have turned up nothing. When we listen, we hear only silence, and when we look, we find nothing.”

“I’m interested to know to which attempts to demonstrate any alien visitation of our planet the author refers to ? Can we honestly state we really have seriously tried ? I think that this is an interesting domain to explore.”

Very little in terms of serious scientific effort. NASA certainly is not doing any such thing. Heck, they backpedaled like crazy when the Mars Phoenix lander showed clear evidence of liquid water on its landing legs in 2008. And fossils on the Red Planet? Yikes, no! So forget looking for alien artifacts.

We may not even have decent funding for future planetary missions, so it is a guarantee that in addition to the social and professional stigma of wanting to search for alien artifacts in the Sol system, there will be no funding for such a mission for a very long time.

Unless private efforts come into play, then we have to worry that the benefactors of such a mission will be doing it to see what they can get out of such a find for themselves before any benefits to science.

coacervate December 10, 2013 at 12:23

@Nick, listen up.

“Traditional SETI searches for alien radio signals have, by this time, similarly extended the process of elimination of peer civilizations from nearby stars.”

I have asked you to list the searches that have achieved this notable milestone. Since they have not been done, to my knowledge, wouldn’t you be better to rethink your assumptions and do some research of your own? See ljk’s post, for which I am grateful, showing the appalling gaps in our SETI work as a species. The SETI Talk/Science ratio is enormous. Just visit the SETI Institute, your one stop shop for all your seti needs.

As Carl (and Seth and …) said, if we don’t listen we’ll never know. The USA can’t pay for research and is annoyed by its depression. OK we know the USA is lost “in the hot mazes”…now we have Russia or communist red China for new science. “O! Waste of loss, and by the winds, grieved, ghost come back again.”

To think that at this very moment, signals from another civilization are gently lapping against the surface of our Earth…unnoticed for years…aeons? Our Weltanschauung is all wet.

ljk December 10, 2013 at 14:15

Please read my article on the book Civilizations Beyond Earth: Extraterrestrial Life and Society, linked here:

http://www.centauri-dreams.org/?p=27889

In particular check out the link within my article to this online book, SETI: A Critical History:

http://www.daviddarling.info/encyclopedia/S/SETI_critical_history_contents.html

Dr. Stuart Kingsley began a valiant fight to bring back Optical SETI into the mainstream SETI fold after it was first proposed by the inventor of the laser in 1960 and subsequently sidelined by the radio regime until the 1990s. See the real history here:

http://www.coseti.org/introcoseti.htm

Regarding SETA, the Search for Extraterrestrial Artifacts, this page has some useful references:

http://www.daviddarling.info/encyclopedia/S/SETV.html

In summation, while it is noble that we humans have tried SETI at all and it has been kept going by some smart and brave individuals for the past half-century, it is really time to not only get some serious funding for these projects but to do more than just token efforts to look beyond the radio spectrum. As you have seen in the pieces I have linked to above, the science of SETI has been “victim” to a rather old paradigm which has limited us in many ways.

Dr. Kingsley made a bold strike to expand SETI by fighting to have it extend into the optical range. Others have made a few efforts to look for probes and Dyson Shells. It is the 21st Century: Time to use current technology and thinking for discover who and what else is out there in the Universe.

ljk December 10, 2013 at 14:37

Finally, I found the long list of SETI projects since Ozma I have seen published in several print places in past years. It is not current but it gives a good list of just about all SETI efforts since 1960:

http://www.daviddarling.info/encyclopedia/S/SETI.html

This list certainly shows the sporadic and token nature of most SETI efforts since Frank Drake’s initial effort, which itself last just a few months and looked at only two stars.

FYI: How many of you knew that the Soviet Mars 7 and Venera 11 and 12 probes were involved in SETI? Along with the American Pioneer Venus Orbiter, though in true SETI tradition they were not the main objectives of the instruments available.

Wojciech J December 10, 2013 at 15:28

ljk December 9, 2013 at 9:59
“One would hope that an advanced civilization would have eliminated light pollution. You and the authors are also assuming that aliens need to illuminate their cities like ours (if they also even build cities) and that these beings want to live on the surface of their worlds – or even live on Earthlike planets at all.Again, aliens will be ALIEN. clearly Star Trek and its kind have long polluted our notions of ETI.”
I doubt we will eliminate light pollution, unless we change radically our biology. It isn’t a concern of high priority anyway to society, and some light will remain(night clubs, street lights, ships, illumination of historic buildings etc, etc). As to searching for city lights-as good attempt as any other one, since we have base our search on something. Of course you could also search for heat signatures(I believe Colossus telescopes is designed for this) or signs of artificial manipulation of landscape.
We could imagine civilizations able to conceal most this(although heat would be very difficult)-but in such as scenario they would actively conceal themselves and make our search irrelevant in the first place.

ljk December 10, 2013 at 10:35
Philippe Ailleris said on December 10, 2013 at 3:13:
“Great article and just a request for clarification concerning the above statement: ”…but also the attempts to demonstrate any alien visitation of our planet or our solar system have turned up nothing. When we listen, we hear only silence, and when we look, we find nothing.”

“I’m interested to know to which attempts to demonstrate any alien visitation of our planet the author refers to ? Can we honestly state we really have seriously tried ? I think that this is an interesting domain to explore.”

Very little in terms of serious scientific effort. NASA certainly is not doing any such thing”

This is only partially true. While not researching UFO’s(which would bring it too close to lunatics for comfort), NASA in the past did research possibility of alien artifacts beyond our Solar System in form of Dyson Spheres, surprisingly getting interesting results.
IIRC there are currently at least three research projects by mainsteam scientiss searching for presence of mega-engineering artifacts in our Galaxy sponsored by Templeton Foundation(Geoff Marcy’s is one of the three I believe).

http://newscenter.berkeley.edu/2012/10/05/grants-help-scientists-explore-border-between-science-science-fiction/

Heath Rezabek December 10, 2013 at 15:34

@Nick – The backwards compatibility you speak of is why and how archival becomes a mitigation of Xrisk. If the body of Earth-originating knowledge can move forwards in time without losing too much access to its prior knowledge, it is effectively building a broader and broader base from which to be a peer civilization someday. If knowldge is lost and only ever spottily recovered, we lose the potential to peer up, as it were, in the fullness of time.

Rob Henry December 10, 2013 at 16:15

Eniac, sure, kinetic energy is proportional to the square of speed, but earlier you claimed, that this was also the relationship for energy dissipation need from hitting the ISM when that is actually a cubic relationship (before relativistic effects)

ljk December 10, 2013 at 16:25

Wojciech J:

Is this the Dyson Shell search you are referring to? I am not certain that NASA was involved. At least it is not obvious from this page:

http://home.fnal.gov/~carrigan/infrared_astronomy/Fermilab_search.htm

While I am glad to see mainstream astronomers conducting some out-of-the-box SETI, I worry about the ulterior motives of their funding source: The Templeton Foundation. They should be getting grants from the NSF, but not in this economic climate.

As for light pollution, again my point is not whether we will continue to ruin our skies with ugly excesses of artificial lights, but whether a sophisticated alien species would do the same – assuming they live in cities above ground and such. Unless the galaxy’s inhabitants are like the ones in Star Trek, I expect real aliens to be, well, alien to humans.

I suppose, following this tack, we should look for signs of their industrial air pollution as well. The question is (he says only somewhat facetiously), do we really want to meet mirrors of current ourselves?

Paul Gilster December 10, 2013 at 18:04

Run a search on ‘carrigan’ in the search engine here and a lot of stuff on Richard Carrigan and his work on Dyson spheres (and other forms of ‘interstellar archaeology’) will turn up. I also write about him in Aeon Magazine in the context of hunting for mega-engineering projects:

http://aeon.co/magazine/nature-and-cosmos/searching-for-the-archaeologicalruins-of-alien-civilisations/

To my knowledge, though, NASA has not done any Dyson sphere work, though of course Carrigan uses data gathered from missions like IRAS.

Wojciech J December 10, 2013 at 20:43

“As for light pollution, again my point is not whether we will continue to ruin our skies with ugly excesses of artificial lights, but whether a sophisticated alien species would do the same – assuming they live in cities above ground and such. Unless the galaxy’s inhabitants are like the ones in Star Trek, I expect real aliens to be, well, alien to humans.”
Well they might not, but based on other lifeforms we know, eyesight is a common feature and nocturnal life forms face certain limitations that might not be civilization-friendly.City lights and production of heat/fire is common attribute of any technological society we know, so we have start based on what we know
Finding more exotic aliens would be counter-productive due to exotic environments and conditions in which they would arise, and thus limiting targets.Doesn’t mean that they possibly don’t exist, but finding sub-ice civilizations living on Europa-like moons that are still in their version of Middle Ages would be a bit difficult(and unlikely to the time difference).
And as mentioned before the detection by telescopes isn’t limited to observing city lights but many more possible technosignatures.

Paul-thank you for the clarification-that is what I meant. It might be worth mentioning that search for Dyson Spheres was done several times, also in Russia I believe.
It will be interesting what the projects started in 2012 will bring.
It might be worth asking for example here
http://www.personal.psu.edu/jtw13/blogs/astrowright/

I think Jason T Wright started a project for this using WISE data in 2012.

coacervate December 10, 2013 at 21:58

If cavemen were searching for “advanced civilizations” they might wrongly search for great piles of flint flakes because that was what they thought of as advanced technology. We are similarly silly to look for Dyson spheres.

KIS. The ISM is most transparent to radio and light. Look there first. There may be beacons. Check for those first, then get fancy or give up, but one step at a time.

Eniac December 10, 2013 at 23:34

Rob, you are correct, heat dissipation is cubic. Not only is the ISM faster (linear) and more energetic (quadratic), but there is also more of it being absorbed per unit of time (cubic). Similarly, for momentum, we get a quadratic relationship, I suppose. The conclusion is still the same: heat is a factor of c more serious than drag.

ljk December 11, 2013 at 0:59

Why the Hunt for Extraterrestrial Life is Important

DEC 5, 2013 06:58 PM ET // BY IAN O’NEILL

On Wednesday, something remarkable happened at Capitol Hill. In a special hearing, lawmakers of the House Science Committee discussed the search for extraterrestrial life with three experts for 2 hours. The question and answer session focused around efforts to find everything from alien microbes under rocks on Mars to full-blown SETI efforts to seek out transmitting extraterrestrial intelligence.

Naturally, some of the questioning was naive and sometimes needlessly lighthearted. In response to the Republican-led House panel, a Democratic opposition group even seized the opportunity to mock the occasion. The hearing was significant; maybe not to the immediate day-to-day running of a nation or the lawmakers who saw it as an entertaining sideshow, but the three scientists invited to talk were dead serious about the opportunities and implications such a high-profile hearing can bring.

“In our Milky Way galaxy there are 100 billion stars and we now believe, in our universe, we have 100 billion galaxies,” said Sara Seager, Professor of Physics and of Planetary Science at M.I.T., at the hearing titled Astrobiology: The Search for Biosignatures in Our Solar System and Beyond. “So if you just do the math, the chances that there’s a planet like Earth out there with life on it is very high.”

Full article here:

http://news.discovery.com/space/alien-life-exoplanets/why-the-hunt-for-extraterrestrial-life-is-important-131205.htm

ljk December 11, 2013 at 10:53

Wojciech J said on December 10, 2013 at 20:43:

“Finding more exotic aliens would be counter-productive due to exotic environments and conditions in which they would arise, and thus limiting targets. Doesn’t mean that they possibly don’t exist, but finding sub-ice civilizations living on Europa-like moons that are still in their version of Middle Ages would be a bit difficult (and unlikely to the time difference).”

And that is the problem with current SETI: We are limited by our technology and what we know. Do you really think we are going to find versions of ourselves out there? Evolution says that is unlikely.

If you read the pieces I have linked to in this comment thread, you will see how the mainstream SETI community and others are almost trying to force alien life to fit into our mold of what we think it will be like, because we can only do so much stuck on this one planet with the tools we have. As Carl Sagan said, the Universe certainly is not obliged to fall into line with our wishes and perceptions.

This thinking that some altruistic version of us is out there sitting on an Earthlike world transmitting hello signals into the galaxy to engage in a scientific discussion is one big reason why current SETI has yet to succeed. They are not like us and this is not Star Trek. We have to change the parameters and paradigms of SETI, or it is another fifty years at the radio telescope listening to silence.

James Benford December 11, 2013 at 13:19

Ljk incorrectly attributes to Wojciech my remarks about detecting artificial lighting on exoplanets. He refers to a press release, which may have been what has led him astray.

Loeb is quoted in that news release: “Looking for alien cities would be a long shot, but wouldn’t require extra resources.” But the writer doesn’t make clear Loeb’s talking about detection of alien cities in the Kuiper belt, ~50 AU out.

The paper that news release is based on (Detection Technique for Artificially-Illuminated Objects in the Outer Solar System and Beyond, Abraham Loeb and Edwin L. Turner) makes that clear:

“Existing and planned optical telescopes and surveys can detect artificially-illuminated objects comparable in total brightness to a major terrestrial city out to the outskirts of the Solar System.” They add a caveat that this requires long observing times.

As for detecting artificial lighting on exoplanets, the paper says otherwise. Little is said about it because it’s so extremely hard to do. They make that clear only on the last page, referring to exoplanet city detection:

“….the night side needs to have an artificial brightness comparable to the natural illumination of the day side. Clearly, the corresponding extraterrestrial civilization would need to employ much brighter and more extensive artificial lighting than we do currently since the global contrast between the day and night sides is a factor ∼ 6 × 105 for the present-day Earth.”

So claims of the detectability of exoplanet cities by artificial lighting are misunderstanding the meaning of the paper. Yes, in Centauri-Dreams we hear of unquantified ‘hypertelescopes’. To be serious in such ideas, I keep saying, one must quantify! So I did a rough estimate. The scale of such ‘hypertelescopes’ I calculate to be roughly 10 km aperture in the visible. At current prices, that would cost on the order of the Earth’s annual GDP. Daunting unless they’re a supercivilization, and we’re back to observable issue, as above: Where are the observables of this nearby supercivilization?

Wojciech J December 11, 2013 at 15:48

“And that is the problem with current SETI: We are limited by our technology and what we know. Do you really think we are going to find versions of ourselves out there? Evolution says that is unlikely.”
Actually evolution says that certain patterns are repeatable. You will find common traits that evolved independently from each other. Using light or heat btw isn’t a matter of evolution but technology. A civilization without the need to use heat would be very, very exotic and likely irrelevant due to its undetectability.
James Benford
“So I did a rough estimate. The scale of such ‘hypertelescopes’ I calculate to be roughly 10 km aperture in the visible”
Only if you would build a single gigantic one which nobody is actually thinking of.
Most models assume swarms of satellites coordinating between each other
http://4.bp.blogspot.com/_VyTCyizqrHs/S9prxDIjLCI/AAAAAAAAHeU/9A075cRf9oY/s1600/exoearthimager.jpg

http://1.bp.blogspot.com/_VyTCyizqrHs/S9ptNOYAxiI/AAAAAAAAHe0/FVdOdpXiczc/s1600/laserhyperscope4.jpg

https://lise.oca.eu/IMG/file/HypertelescopeOpticalObservatoryLabeyrieESA.pdf

Which based on current advanced in 3d printing and swarm coordination doesn’t seem to be so far off.

http://www.youtube.com/watch?v=ShGl5rQK3ew (an example of technology that could be helpful in designing such telescope swarms)

Certainly far more likely than billion-year old radio beacons constantly sending signals to Earth(which they would have to spot first anyway).

As to GDP it was 1,102 billion dollars (1990 value) in 1900 and 45,730 in 2012(not that hyper telescope would cost that much)

“Where are the observables of this nearby supercivilization?”
First of all it wouldn’t have to be near, second of all, as primitive civilization would be destroyed culturally by contact with one advanced millions of years ahead, it probably isn’t interested in destroying potential unique civilization providing new ideas, science and entertainment. Either that or it is indifferent, unable or unwilling to manifest itself.
And of course having such hyper telescopes is a question of 20-50 years of development for our civilization, by then we certainly wont be a supercivilization either.

Eniac December 11, 2013 at 23:22

Sara Seager (via ljk):

“So if you just do the math, the chances that there’s a planet like Earth out there with life on it is very high.”

Sorry, Sara, but this is clearly wrong. If you do the math, with 100 billion stars in each of 100 billion galaxies, the best you can do is say that the chance for life to arise spontaneously around a randomly chosen star needs to be 10^-22 or higher. Otherwise we’d be alone in the universe. The math involved here is the Poisson distribution. However, no amount of math will tell you whether 10^-22 is a high or low estimate for this chance. The chance for life to arise around a star could be 10^-50, or 10^-googleplex, for all we know. Anything less than 10^-22 means we are alone, and there is no evidence whatsoever to indicate it is higher than that.

Eniac December 12, 2013 at 0:16

The key thing to remember here is that there is no such thing as an unreasonably low probability. The chance of throwing 100 heads in a row is less than 10^-22. Why couldn’t the chance of life forming from non-life on a given planet be that small? We simply have no idea. It could well be. The assumption that it is not, implicitly made by Sara Saeger in the above sentence, is unfounded and definitely not a result of “doing the math”.

Also note that our own existence proves nothing, it is assured by selection bias. The only way to assess the probability is by looking at other worlds. We have found nothing, which may be taken as an upper bound. There will not be a lower bound until we find actual evidence for true extraterrestrial life, i.e. life that did not originate on the same planet as ours. Until then, the probability of abiogenesis may consistently be assumed to be arbitrarily small.

Highest respect to Dr. Saeger, of course. I am sure she took legitimate creative license or perhaps was quoted out of context.

Eniac December 12, 2013 at 0:29

James Benford: Is your calculation of the aperture of a hypertelescope based on resolution, light gathering ability, or both? Does it take signal to noise issues into account?

To me, the notion of detecting city lights on exoplanets seems ludicrous, and I am glad you thoroughly debunked that citation that appeared to say otherwise.

James Benford December 12, 2013 at 4:16

Wojciech J: Sure, a large set of small optic elements can be used instead of a single large one, as long as the total area of these adds up to the area I calculate as many square km. So the cost does not decline. That’s because of the ‘thinned-array curse’, as it’s called. If a transmitting antenna is filled by an area-fraction F (F< 1), then the power that is lost by emission into side lobes of the beam (and hence is NOT directed into the main beam) is proportional to 1-F. A receiving antenna has the same property; a large receiving array will simply not get the photons for greater signal detection.

Re: observables of a supercivilization: If it’s not nearby, it must be even more ‘super’ to se cities because of inverse-square. If we use the ability to build larger area telescopes as an indicator of the scale of civilization, the energies consumed by that civilization would be larger by similar amounts. Are there then no other observable features of such civilizations? I doubt it, especially if they are to be nearby. Our SETI observations exclude nearby super civilizations. We’ve been looking at nearby stars for microwave transmissions for half a
century: no detections.

Suppose there were a supercivilization at Alpha Centauri. They would be able to do extraordinary things that might modify their climate, beam power around their solar system, launch rockets or beam-powered sails in our direction. Many of these consequences would be observable. So, where are they? Further away, they have to be even more powerful.

ljk December 12, 2013 at 10:04

Eniac said on December 12, 2013 at 0:16

“Highest respect to Dr. Saeger, of course. I am sure she took legitimate creative license or perhaps was quoted out of context.”

She was talking to a group of politicians. I am surprised she did not have to explain to them first about how Earth goes around the Sun and not the other way around. Some of their actual questions for the scientists there were not far from such rudimentary levels.

I suppose we should be amazed and grateful this happened at all in DC. Unless you are a Democrat. :^)

ljk December 12, 2013 at 10:13

Wojciech J said on December 11, 2013 at 15:48:

[LJK] “And that is the problem with current SETI: We are limited by our technology and what we know. Do you really think we are going to find versions of ourselves out there? Evolution says that is unlikely.”

“Actually evolution says that certain patterns are repeatable. You will find common traits that evolved independently from each other. Using light or heat btw isn’t a matter of evolution but technology. A civilization without the need to use heat would be very, very exotic and likely irrelevant due to its undetectability.”

I am focusing more on behaviors and thoughts than mere physical boundaries. Assuming life elsewhere isn’t too exotic, even the forms we might recognize could have very different thoughts and attitudes on existence. Look at the varieties of human cultures across this one small globe.

I gave an example in the article I link to below about the Jesuits coming to “convert” the Native Americans in Eighteenth century Canada. Same species separated by a few thousand miles of ocean, but their views on the world and the afterlife could not have been more different. They did not even share the same words for certain concepts.

The Jesuits assumed by their logic that everyone would come to the conclusion that a Judeo-Christian God exists. They were quite mistaken. Just as many SETI folks think mathematics will be the common language between all intelligent species no matter how different and distant. I think we may be in for another rude awakening.

http://www.centauri-dreams.org/?p=27889

You can and did say that if aliens were too exotic then they would be irrelevant for our purposes. Well, what if humans are the exotic ones and that is why ETI have yet to bother with us? Or that we are just not sophisticated enough to understand the Universe and how to approach finding and communicating with others?

ljk December 12, 2013 at 10:17

James Benford said on December 12, 2013 at 4:16:

“Suppose there were a supercivilization at Alpha Centauri. They would be able to do extraordinary things that might modify their climate, beam power around their solar system, launch rockets or beam-powered sails in our direction. Many of these consequences would be observable. So, where are they? Further away, they have to be even more powerful.”

What if they all moved underground to live out their lives in virtual fantasy worlds of their own making and choosing? We appear to be heading in that direction ourselves.

swage December 12, 2013 at 12:22

@Eniac

” the chance for life to arise spontaneously around a randomly chosen star needs to be 10^-22 or higher”

I am not so sure. We can not securely assume life arose on Earth conclusively at this time. What we can assume is how much life bearing material from was spread from Earth. If you do the math, assumed hardy organisms can survive the voyage (a scenario for which is supporting evidence seems to be increasing steadily) Life may have very well spread through the entire galaxy already.

If the point of origin of life in this region of space is Earth, you can expect infected Planets in neighboring systems, for Earth has been seeding for approximately 3.8 billion years. Even at sub-light-speed this covers an impressive area.

If the point of origin of life in this region of space isn’t Earth, which is more probable by chance and also explains why we have such difficulty pinpointing out the process of the origin of life on this planet (a scenario for which zero evidence exists), then i wouldn’t expect any uninfected habitable planets in the neighborhood at all.

Then there is also a scenario where infection occurs through direct intervention by sentient beings, improving infection probability by quite a few orders of magnitude (as opposed to “natural” random chance).

The scenario where Earth is the big exception and a totally closed system seems the least probable of those to me. It seems anti-copernican to me, assuming Earth being coincidentally again the center of the cosmos, even if only in a biological context. This seems more being a religious context where humanity can retain its crown of creation, for what its worth.

When the JWST goes online, we will know. That’s what Saeger was referring to. I am not expecting Earth being the center of all things. This has been a continuous mistake on our side and was each time refuted as our observation capabilities improved.

Even acknowledging Big Bang Cosmology, one has to ask if such an even happened – which it very clearly did, how OFTEN such events happen. There are no singular cases, no exceptions. If the pre-Big Bang environment allows such a scenario it allows such a scenario necessarily on an INFINITE scale, not just once. Closed systems do not work. Never have and never will, because you need a system outside a closed system to bring it into existence, which is contradictory in itself and therefore irrational.

Wojciech J December 12, 2013 at 19:43

James Benford December 12, 2013 at 4:16
“Wojciech J: Sure, a large set of small optic elements can be used instead of a single large one, as long as the total area of these adds up to the area I calculate as many square km. So the cost does not decline. ”
Well, obviously launching many small payloads that would self-organize into observing network would be less costly then constructing/launching one huge telescope. Costs would be even less if we would be able to use asteroids and in-space resources to start an automated facility to produce such telescopic swarm. In any case I doubt it would cost as much as the worlds whole GDP.

Re: observables of a supercivilization: If it’s not nearby, it must be even more ‘super’ to se cities because of inverse-square. If we use the ability to build larger area telescopes as an indicator of the scale of civilization, the energies consumed by that civilization would be larger by similar amounts. Are there then no other observable features of such civilizations? I doubt it, especially if they are to be nearby. Our SETI observations exclude nearby super civilizations. We’ve been looking at nearby stars for microwave transmissions for half a century: no detections.

Suppose there were a supercivilization at Alpha Centauri. They would be able to do extraordinary things that might modify their climate, beam power around their solar system, launch rockets or beam-powered sails in our direction. Many of these consequences would be observable. So, where are they? Further away, they have to be even more powerful.

“Our SETI observations exclude nearby super civilizations. We’ve been looking at nearby stars for microwave transmissions for half a century: no detections.”
Except of course that Dyson sphere search DID come up with inconclusive results. I am half-serious here, since the authors themselves are very reserved about this, but still,these searches didn’t come up empty handed.

“Suppose there were a supercivilization at Alpha Centauri. They would be able to do extraordinary things that might modify their climate, beam power around their solar system, launch rockets or beam-powered sails in our direction. Many of these consequences would be observable. So, where are they? Further away, they have to be even more powerful.”
See what you describe is something we can imagine and probably do within 100, maybe 300 years. Let’s be pessimistic about technology development and say 1000 years.
But what about 1 million ? 100 million ? What can a civilization old 100 million do ? Will it even exist anymore ?
Because the timescales and distances we have to take into account are in million of years and probably thousands of light years.
What we can do, is search for life first and mega-scale artifacts later. Personally I doubt there is any civilization existing or willing to contact us.
At best we can hope for detecting either its remnants or activity.

Eniac December 12, 2013 at 23:56

swage: You are right that IF you assume life can spread without intelligence, it may have spread already. It would be then be much more plausible that there are ETI out there, sharing our biological ancestry, even if the probability of abiogenesis were a lot smaller than 10^-22.

Still, even in that case, the same reasoning applies, in a slightly modified form: If the chance of abiogenesis is below 10^-22, our kind of life will be unique in the universe. Wherever you go, you will be able to trace the biology back to the original abiogenesis, and there will be many commonalities in the basic chemistry of life. Nothing truly different. Just as we find that here on Earth everything is related in a single tree of life. Is that not just as anti-Copernican (your term) as being alone as an intelligent race?

The reason this alleged anti-Copernicanism does not bother me is because it really isn’t. What we are talking about is not a privileged position, but a very high hurdle. There is nothing wrong with a very high hurdle, as long as it is universal and applies everywhere, in good Copernican fashion. It only seems anti-Copernican from our point of view, we who necessarily live on the world (or one of the worlds?) where, by incredible luck, it happened. It is not some privilege, but logical necessity that puts us at this very spot. Quite possibly the only one in the universe. At a random location, mind you, as Copernicus would have wanted.

But, back to Panspermia, I do not think that microbial life could 1) escape the gravity well of the host star, 2) survive millions of years in interstellar space, and 3) happen to be aimed at a target system, 4) hit a planet in the short time of transit on a hyperbolic trajectory, 5) survive the “landing”, and 6) find suitable conditions there to germinate and thrive. If you do the math, each one of these is exceedingly unlikely by itself, together they appear completely prohibitive. Notions that are out there to the contrary are, in my opinion, wishful thinking or worse.

Rob Henry December 13, 2013 at 19:52

I love Eniac’s comment that p(l) could be 10 -^googolplex. As he probably knows, there are problems with that – namely it implies things about the abiogenic potential of our universe that seem rather strange, yet it is possible. What I love is that it still allows us FTL travel in the face of the Fermi paradox without having to go to desperate places like the zoo hypothesis.

ljk December 17, 2013 at 13:08

A quote from the SF novel His Master’s Voice (1968), by Stanislaw Lem:

“The myth of our cognitive universality, of our readiness to receive and comprehend information absolutely new — absolutely, since extraterrestrial — continues unimpaired, even though, receiving the message from the stars, we did it with no more than a savage who, warming himself by a fire of burning books, the writings of the wisest men, believes that he has drawn
tremendous benefit from his find!”

ljk December 18, 2013 at 10:43

The Planetary Society is reviewing all of the original Cosmos series by Carl Sagan. This is episode number 8, which is about interstellar travel:

http://www.planetary.org/blogs/casey-dreier/2013/20131217-cosmos-with-cosmos-episode-8-journeys-through-space-and-time.html

ljk December 26, 2013 at 11:41

When will we become interstellar? An interview with Ian O’Neill:

http://www.universetoday.com/107504/when-will-we-become-interstellar/

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