Some day alien civilizations may pick up television or radio signals from Earth. But does this mean they’re likely to visit us? Danish researcher Rasmus Bjørk (Niels Bohr Institute, Copenhagen) doubts it. “Even then, unless they can develop an exotic form of transport that gets them across the galaxy in two weeks it’s still going to take millions of years to find us,” says Bjørk in an article in The Guardian. “There are so many stars in the galaxy that probably life could exist elsewhere, but will we ever get in contact with them? Not in our lifetime.”
Bjørk is in the news because he set up a computer simulation to investigate how long it would take to explore the galaxy. Suppose we build eight probes which, along the way, send out eight more mini-probes, all headed for different stars that are likely to have life. Bjørk’s plan is to search only within the galactic habitable zone, to use flyby probes only, and to fan out the spacecraft at one tenth the speed of light. The aim is to investigate a volume of space containing 40,000 conceivably life-sustaining stars.
Here’s the method, from Bjørk’s paper on the subject:
The 40,000 stars are explored by sending out one host probe which travels to some faraway star referred to as the “destination star”. Once the probe arrives, it dispatches a number…of smaller probes, that in total investigate the 40,000 nearest stars. They do this by always moving to the star nearest to their current location that have not been explored already. The distance and position of this star can easily be determined from its parallax. After all the 40,000 stars have been explored the probes return to the destination star, where they dock with the host probe for maintenance and prepare to travel to a new destination star.
In other words, explore all 40,000 suitable stars within the box defined by Bjørk and the process begins again on a new box of stars. In this way the exploration wave moves through the galaxy. The results aren’t encouraging for those in a hurry: using eight probes, each with eight sub-probes, the time to explore a box of 40,000 stars is on the order of 100,000 years. Exploring a mere four percent of the entire galaxy takes a time comparable to twice the age of the Earth (specifically, 9.57 x 109 years).
An obvious objection is that self-replicating probes could do the job much more efficiently and in far less time (Frank Tipler has done interesting work on this question, arriving at times in the millions of years to explore the entire galactic disk). But Bjørk points out the problems with such probes. They might easily move beyond control of the humans who designed them, with fatal consequences. So he bases his study on non-replicating devices, reaching this possible answer to the Fermi Paradox: “We have not yet been contacted by any extraterrestrial civilizations simple because they have not yet had the time to find us. Searching the Galaxy for life is a painstakingly slow process.”
The paper is Bjørk, “Exploring the Galaxy using space probes,” accepted by the International Journal of Astrobiology and available as a preprint. A key Frank Tipler paper is “Extraterrestrial intelligent beings do not exist,” Quarterly Journal of the Royal Astronomical Society, Vol. 21 (1980), pp. 267-281.
Addendum: This thought from Adam Crowl on the Bjørk paper mirrors my own reaction:
Many assume that as soon as intelligences can make autonomous self-replicating robots then that’s what they’ll do, sending them forth with a ‘mission’ to colonise the galaxy with their kind of intelligent life. A self-replicator smart enough to be called ‘intelligent life’ is a ‘person’ in my view, but an arguably important aspect of personal identity is freedom and creativity, and I suspect even the longest-lived ‘persons’ will fatigue in the face of a task like colonising every star in the Galaxy. A more organic expansion will be what eventually completes the task and there’s no easy way of estimating how long, or how thorough, such an expansion will be.
Nice article. If anyone knows of a place where similar articles are grouped, I’d love to read through the resource.
-Zen Blade
I have always thought that the main reason we have not
detected ETI or nor they us is the sheer size and vast
numbers of star systems in our Milky Way galaxy to
explore.
Now take that one 100,000 light year wide galaxy with its
400 billion stars and mulitply that by 100 billion, the estimated
number of other galaxies in the Universe. And if we exist in
a Cosmos of infinite universes – hoy!
Science fiction like Star Wars and Star Trek which make it
look easy to zip around the galaxy in mere minutes do a great
disservice in terms of helping the public appreciate just how
big the galaxy, to say nothing of the Universe, really is.
You don’t have to travel too many light years before our
star, Sol, which seems so bright to nearby Earth, is a dim
blip against a background of billions of stars. And as for
our electromagnetic transmissions, deliberate and otherwise,
they are mostly faint noises in a shell a mere 200 light years
across, competing with a much noisier natural background.
Plus, being stuck on this one planet for generations has led
us to keep thinking that we are the focal point of all existence.
Maybe other intelligences think this way as well and are
waiting for us to call them – at least the ones who do not
have a truly cosmic perspective on existence.
As for the really advanced space-faring societies – they
probably see about as much need to contact us as we do
your average ant colony. Study us, maybe, but you do
not disturb your subjects.
The paper fails to take in account of self-replicating seed technology, which will certainly be developed long before we get to the stars (unless the Heim hyperdrive gets developed in the next 20 years).
I think any discussion of ETI and intersteller migration that does not take into account transhumanist ideas such as radical life extension and self-replicating technology are not worth the paper they are printed on.
We will become “transhuman” before we get to the stars.
TV and radio signals fade into the background electromagnetic of space long before they reach the next star.
It makes far more sense to make world imagers and hypertelescopes. We could do a lot with those in the next 5-40 years (within most of the lifetimes of the people who are currently alive). Use those and use gravitational lensing and we can perform spectral analysis of the atmospheres of a lot of planets.
Magnetically inflated telescope structures that are several kilometers across. Formation flying with shading of the stars.
100,000km or 1 million kilometer hypertelescope formations with magnetically inflated 1km+ size lens. If we had the will could be done in 40 years.
http://durance.oamp.fr/lise/seminaires/imagesLabeyrieFormationFlight.pdf
Kurt9: This wouldn’t happen to be related to the Heim Theory, would it? http://en.wikipedia.org/wiki/Heim_Theory
To me, there is likely life in our galaxy. However, is it intelligent?
Hi All
Kurt9 opines that the paper doesn’t take into account self-replicating technologies, but I thought Paul’s comment (and my own) was quite clear on that point, that self-replicating systems are inherently unstable on such a mass-deployment as colonising the Galaxy. Besides any system intelligent enough to adequately explore the Galaxy is also liable to “purpose drift” and eventually abandoning the “Petri-Dish Crusade” for something better to do. I suspect all such “crusades” will eventually end up following the percolation pattern of space-filling that Geoff Landis has explored…
http://www.sff.net/people/Geoffrey.Landis/percolation.htp
…I’m not saying that his model is the be-all and end-all but I’m yet to see a convincing argument that colonising the Galaxy is desirable or necessary for any transhuman intelligence. Holding over the urge to endlessly replicate from our biological origins is something I doubt transhumans will do. Perhaps you’re thinking probes will just replicate to send on further explorers – maybe so, but how then do you self-limit their self-replication in a stable way across billennia?
In relation to Brian Wang’s very interesting link to the
hypertelescope concept, see here:
The following news clip is from the very first issue of
Cosmic Search magazine from 1979. You can find
all 13 issues online here:
http://www.bigear.org/CSMO/HTML/CSIntro.htm
Holography or 3-Dimensional Mapping of Entire Universe Possible with Bold Soviet Concept for Space Telescope
In a recent report of the Academy of Sciences of the USSR’s Space Research Institute, 23 Soviet scientists including N.S. Kardashev and I.S. Shklovsky, have proposed a radio telescope of remarkable characteristics. The report entitled the “Infinitely Built-Up Space Radio Telescope” envisions telescopes up to 10 kilometers in diameter assembled from many smaller modules of 200 meter diameter. The problems of delivering, assembling and aligning the modules in orbit are discussed.
It is further proposed that two or more such telescopes be arrayed as an interferometer with a 20 astronomical unit baseline. This would involve placing the telescopes at approximately the orbit of Saturn. With such an interferometer operating at wavelengths of a few centimeters the entire universe lies within what is called the “near-field” or “Fresnel zone” of the antenna. What this means is that, in principle, it would be possible to determine the distance, size and shape of every observable object in the universe, producing holographic or 3-dimensional figures of the entire cosmos. This proposal is a bold concept which indicates that radio astronomers are still far from the end of their tether.
The authors of the report point out that such a system could also be used to advantage for the detection of extraterrestrial civilizations (SETI). For example, planets the size of the earth could be detected from their thermal radiation alone at distances of 100 light years and planets like Jupiter at 1000 light years. Artificial radiation might be detected at much greater distances, possibly bringing millions of planets within range.
Diagram with article:
http://www.bigear.org/CSMO/Images/CS01/cs01p29l.jpg
It strikes me that so much of our discussion can only have validity if a singularity doesn’t occur. With so many singularities coming at our civilization in the next couple of decades — or less — the concept hangs over every discussion here…..a big lump under the rug. If we do, for instance, develop nanobots that “get away from us,” space exploration will be forever altered. If someone at Monsanto engineers a “plant that cannot be killed” or the Internet becomes conscious from a million script kiddies gone amuck, we’re not going to find the above exploration concepts on our front burners.
It’s as if we’re the guys shooting a rocket out into space, but knowing that ten years from now, rockets now on the drawing table will be built and will be so fast that they’ll pass the rockets we’re launching today….so why bother with today’s launch? The best laid plans. . . .
It seems that many singularities could be so much more “close to us” than any truly meaningful leaps forward that present day science can hope to achieve in space exploration the near term.
If we do find an ET signal, that might be a singularity in terms of its impact on our civilization. Yeah, “canals on Mars” didn’t ruin our civilization, but that was when the world was young — today, most of the world would far more deeply grok what an actual ET contact meant. Hollywood has treated the subject endlessly — we’ve all “exercised our brains” in grasping the variety of responses that an ET contact might evoke. So if we do find an ET signal, humanity is a far different beast than what was on earth when the radio show told everyone in New Jersey that the Martians had landed and were on a killing spree. Today’s humanity is “loaded” and ready to pop if a true contact is made. How it will pop is anyone’s guess, but I think it would be as if a singularity had occurred. Around the globe religions would shudder, governments would bristle, and the lower half of the bell curve would create a “popular” response — it won’t be pretty.
It would be a huge stress upon every mind on the planet — and under stress, things break.
Edg
We may have more knowledge, better technology, and a bit
wider perspective than our recent ancestors, but overall we
have not changed much.
If ETI contact were made tomorrow, the reactions depicted in
Carl Sagan’s Contact will look like a cakewalk in comparison
to the real thing.
The beings from this world who will make the first real
contact with beings from another world will not biological.
And they won’t be “spiritual” either, certainly not in any
primitive sense that we understand the notion.
What am I saying? That beings advanced enough to contact
us or visit us directly will not be the organic big heads and
eyes creatures from the tabloids. Instead they will be AIs,
better known as Artilects. And only another Artilect will truly
understand them and their motives.
See more about Artilects here:
http://www.iss.whu.edu.cn/degaris/
and here:
http://www.aeiveos.com:8080/%7Ebradbury/MatrioshkaBrains/index.html
And for the most realistic representation of an Artilect on
film, see The Forbin Project from 1970 (sorry HAL, though
you were close and certainly an inspiration to us all).
http://en.wikipedia.org/wiki/Colossus:_The_Forbin_Project
They won’t be good or evil, they will be so far ahead of
us as to make humanity virtually pointless to them once we
have created them.
De Garis’ vision for the future looks very possible.
Artilects, schmartilects… I agree that such objects could be built, but much like how Nuclear War was going to kill everyone, I doubt AI’s so overpowering or so beyond us –as many currently envision– would exist. Such consolidation of absolute knowledge/power doesn’t occur in a vacuum, which is what must happen for such advanced beings to appear.
The claim that we could create a deity or an uber-being without having the ability to become said being ourselves is just not plausible. It’s like those who claim that cloning technology is somehow the end of all humanity or some monstrous conspiracy to control the world.
And how exactly is a computer with “human intelligence” going to “interface” with everything? Unplug the damn thing, problem solved. Hook it up/don’t hook it up to the internet/wireless devices… If such a system may evolve only once, well then this implies either unique coding or unique physical construction of its “hardware–processor, whatever”. If the latter is the case, then the Artilect is essentially not mobile. If the former is the case, then a computer virus could kill it.
Human intelligence simply means that something has the ability to learn on its own. That doesn’t mean godlike powers. Am I the only person here who believes that if mankind were somehow able to create such an artificial intelligence, he would also be wise enough to have a simple safeguard such as an “off” switch? An Artificial Intelligence is simply a bunch of code, it doesn’t have arms, legs, the ability to rewire itself, etc… (not yet at least). Yes, once it can modify its own code it may develop in a thousand different ways, but it is not a weapon of mass destruction. We destroyed all of those when we took down Saddam.
And again, while this techology is being advanced, other technologies will also be advancing.
Oh, and what about those flying cars? I was promised flying cars. We were ALL promised flying cars.
Seriously though, I can imagine organisms having coding similar to our DNA, and I can imagine said organisms being more intelligent than us, and quicker than us, but the concept of them being more powerful than us (by orders of magnitude) is just fantastical. From my perspective as a biochemist, there would most likely be multiple of these organisms living within the same mainframe (for lack of a better word), perhaps backups during the evolution process. These organisms would then evolve, and perhaps have a society, but why would you EVER EVER EVER let it into the real world? This is like taking a VERY contagious disease from a lab and just walking around with it everywhere… I think I’ll take that small pox vial with me to the Taco Bell down the street…
I know my above writing is abrasive, but this sort of deep blue scare really frustrates me. Scientists are responsible enough to not royally screw up everything. Actually, isn’t there at least one Sci-Fi film or something out there where the intelligent AI is beneficial to humanity?
-Zen Blade
Hi ZB
Tweakie from “Buck Rogers” was beneficial. Debatable about being “intelligence” though.
Adam
I remember seeing the Forbin movie some years after it came out and found its depiction of AI to be unbelievable. Even though I was a teenager I had done my first programming (insert fond memories of S/360 and PDP-8). The movie was funny enough that I laughed at it. Mix a bunch of circuits and some code and *bing!* you have not only a sufficient template for intelligence to function, but it instantly organizes into an intelligent entity, a self, and also a personality, motives, and objectives. How did those pop into existence? And I agree with Zen above the unrealistic circumstances like no off switch, safeguards, and a full cutover to production hardware and software without backups, backouts or anything? Fire the project manager!
I also find it a bit of a stretch to claim any depiction of AI as a realistic representation when we have never experienced an AI/artilect, and certainly could not claim to list the attributes of that artilect. It’s speculation.
Marc,
I was referring to the Heim Theory that you mention, which I have been following developments over the past year. Heim theory has its “bugs” (one has just been corrected), but has an increasing likelyhood of being correct. In any case, Heim theory is the only plausible method of FTL, if it turns out to be correct and if the hyperspace part of it also turns out to be correct. If Heim theory turns out to be wrong, it is very unlikely that a method of FTL is possible (people talk about “wormholes”, but these require tremendous amounts of energy to make) and that intersteller travel will be sub-light.
Regardless of of the possibility of FTL, technologies such as semiconductors, biotech, and nanotech are following a very rapid “Moore’s Law” like rate of develop and will continue to do so for the forseable future. Propulsion and other space technology is not. Given the rate of development of the first kind of technology, it is reasonable to assume that we will become some kind of transhumanist society by the end of this century. I think it unlikely we will be going to the stars in any meaningful manner within this time period.
Assuming that “aliens” follow a similar tajectory of technological develop, is it not likely that they will become transhuman (in this case, trans-alien) society before they go to the stars and, thus, will have self-replicating technology at this point?
Kurt9,
Regarding biotech and how quickly we are advancing, there are some (me among them perhaps) who fear that we have just reached a plateau. I say this because a number of huge discoveries over the past 10-20 years… discoveries one would not have dreamed up 5 years earlier have just been made, and there are now lots of people working on expanding those particular discoveries.
If evolution lurches forward slowly with occasional jumps that result in drastically different creatures, then we’ve just had a couple of jumps in biotech/biology. Before we go up too much higher, we will need to expand our base.
Recent huge discoverie/advances: Sequencing the human genome, siRNA and miRNA, Stem Cell manipulations, Bioinformatics. Riboswitches–may become hugely important for anti-bacterial drug design.
This isn’t to say research is going to slow down, only that there have been so many tremendous advances in the past decade that we are going to need to sit down and parse through everything for a while. Many of the above discoveries have been or will be compared to Watson+Crick’s double helix.
Also, I want to say how important funding is… Funding EXPLODED during the 1990’s… it has not done so recently. The changes in funding levels have huge effects on science and the people going into/leaving academia.
-Zen Blade
One thing that would be cool would be to hear a signal from ETI, and decode it to discover an image of, say, M31, with an unambiguous time stamp and location of where it was taken from. We’d be able to basically instantly compare it to a local shot, and do the parallax math, and find out really exactly how far away it is. Then we could return the favor.
Getting to even “nearby” stars is going to be hard. But the goal seems worthwhile. Two calamities are coming our way. The death of the Sun, and the coming of M31. That should be motivation enough. Taking many generations is hardly an issue.
The Pioneer Plaques and Voyager Records both have similar
methods to what you are referring to. The plaques and the
record covers have diagrams of 14 pulsars which the recipients
can hopefully decode to figure out Earth’s location.
The Voyager Record has as one of its first images the same
pulsar map with an image of M31 next to it. One hope was that
the recipients would have records of similar images of the
Andromeda galaxy and be able to determine to some degree
when the Voyager probes were sent into space.
See here:
http://voyager.jpl.nasa.gov/spacecraft/images/image002.gif
Version 2 of this paper has been released:
http://arxiv.org/abs/astro-ph/0701238v2
From the December 8, 2007 edition of George P. Dvorsky’s
Blog, Sentient Developments.
The problem with 99.9 % of so-called ‘solutions’ to the Fermi Paradox
Non-exclusivity.
Sure everyone has a convenient answer to the Fermi Paradox, but nearly all of them fail the non-exclusivity test. While some solutions to the FP may account for many if not most of the reasons why we haven’t detected signs of ETI’s, they cannot account for all.
For example, take the notion that interstellar travel is too costly or that civs have no interest in embarking on generational space-faring campaigns. Sure, this may account for a fair share of the situation, but in a Universe of a gajillion stars it cannot possibly account for all. There’s got to be at least one, if not millions of civs, who for whatever reason decide it just might be worth it.
Moreover, answers like the ‘zoo hypothesis,’ ‘non-interference,’ or ‘they wouldn’t find us interesting,’ tend to be projections of the human psyche and a biased interpretation of current events.
Full article here:
http://sentientdevelopments.blogspot.com/2007/12/problem-with-999-of-so-called-solutions.html