Solar Systems Like Ours in the Minority

by Paul Gilster on January 6, 2010

William Borucki’s talk about the early Kepler findings on Monday created the biggest spike in traffic I’ve ever seen on Centauri Dreams, enough to blow through our memory allocation and crash the site for about twenty minutes. I had to reboot the server and up the memory to get back online, a tribute to the interest Kepler continues to generate in our community. I’m also getting plenty of comments from people at the American Astronomical Society meeting in Washington. If you use Twitter, use the hashtag #aas to join the ongoing stream of short updates.

Right now Scott Gaudi’s talk on Tuesday is generating the biggest buzz. Gaudi (Ohio State) reported on a gravitational microlensing effort called MicroFUN (Microlensing Follow-Up Network), one we’ve previously discussed in these pages. The method is well understood: One star occults another as seen from Earth. The light of the more distant star is magnified by the nearer one, and any planets around the lensing star momentarily boost the magnification as well. You find planets this way, though they’re not planets likely to be observed again because of the nature of the method.

I love this Gaudi quote from the talk: “Planetary microlensing basically is looking for planets you can’t see around stars you can’t see.”

Gaudi’s team has concluded that about fifteen percent of the stars in the galaxy are orbited by planetary systems like our own, meaning they have several gas giants in the outer part of the solar system. That fifteen percent is telling. “Solar systems like our own are not rare,” says Gaudi, “but we’re not in a majority, either.” Microlensing is useful for this kind of study because the method does a good job at picking up giant planets far from their primary star, a more difficult task with Doppler methods.

Working with colleague Andrew Gould, Gaudi used four years of MicroFUN data and folded in a statistical analysis based on ‘robust assumptions’ and the earlier work of both men. It turns out that MicroFUN in that period of time has revealed precisely one solar system with two gas giants in roughly the configuration of Jupiter and Saturn. Statistically, if every star had a solar system like ours, we should have found about six such systems by now. The slow discovery rate implies only a small number of systems have our configuration, no more than about fifteen percent. Says Gaudi:

“While it is true that this initial determination is based on just one solar system and our final number could change a lot, this study shows that we can begin to make this measurement with the experiments we are doing today.”

And as Gould notes, given the number of stars in the galaxy, even narrowing the odds down to fifteen percent leaves several hundred million systems that could resemble ours. Nor should we assume that a system necessarily has to mimic our own for life to develop within it. Nonetheless, this is an intriguing result that reinforces our sense that extrasolar planetary systems come in a surprising variety, one we learn more about with every new detection.

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Eniac January 9, 2010 at 11:35

To me it seems shielding the radiation is a whole lot easier than uploading minds.

In any case, the first interstellar vehicles will quite certainly be unmanned probes, not very intelligent, and without frozen embryos or uploaded minds on board. They will fly by, not stop. The first ones to stop will probably carry a (non-intelligent) von Neumann seed, programmed to construct an uninhabited outpost in the target system for observation, communication, and possible construction of more probes. People may then choose to follow, shielded and probably in deep sleep, with a habitat ready for them at the destination.

Athena Andreadis January 9, 2010 at 15:34

Along the lines of recent comments, biological systems must be seriously considered as an asset rather than an obstacle for interstellar flight. They are resilient, poised for alternative functions, not dead-ended by forced optimization for single goal… and nanobots already function, and have done so extremely well, for millions of years: they’re called enzymes and miRNAs.

george scaglione January 9, 2010 at 15:53

eniac i just read your comment above and yes sir i think you are 100% correct the first interstellar vehicles will not be any great shakes in fact in what you have said you may have made them just a little too sophisticated as it stands! but yes probably they will be unmanned! i have predicted the first interstellar vehicles (imho) for 2075.i’d like to know what you may have to say. respectfully your friend george

Gary Allen January 9, 2010 at 19:38

Athena said:
“I’m a research molecular biologist working on brain regulation and function, Harvard ‘77, MIT ‘84 (since we’re comparing lengths of belts) and I’m as good in my domain as you are in yours.”

I saw your credentials in one of your earlier links and was suitably impressed (this was one of reasons why I revealed mine). We appear to be roughly of the same generation, i.e. I got my B.S. in Engineering Physics from U.C. Berkeley in 1976 and my Ph.D. in Aeronautical Engineering from Stanford University in 1984. Normally on the Internet, I write under a pseudonym because it’s “career adverse” for an aeronautical engineer to be overly free with his opinions. However I am very impressed with http://www.centauri-dreams.org . I’ve been writing to space exploration forums for over 25 years and never have I seen one of this quality. Normally for a forum like this one, the comment section would be inundated with noise from the mentally ill. Someone has made it their full time job to maintain a very high quality at this website and I thank him/her for doing that.

Daniel said:
“sorry Gary Allen still to much science fiction and less science i don’t buy it”

Check out this link showing a wrecked heat shield on the surface of Mars:

http://www.lyle.org/~markoff/collections/oppsol335R.gif

Most people would call that “science fiction”. For me that’s just another day at the job. Pre-phase-A studies for Mars, Venus and Titan missions, EDL (Entry, Descent and Landing) studies for manned Mars missions or TPS (Thermal Protection System) sizing for the Orion capsule heat shield are what I normally do. When I want to “think outside of the box”, I dream about interstellar spacecraft or civilizations orbiting M class stars.

Daniel also said:
“in my believe of something exotic that could turn up is wormholes.wormholes still under study by theoric physiscs and there lot scientific paper of wormhole eveyday, and there a lot things in Physics that we still don’t understand.”

Wormholes are probably a spurious (nonphysical) solution to Einstein’s field equations or an example of taking a solution beyond the validity of a physical model’s assumptions. Concerning the difficulty in understanding this stuff: A zillion years ago, I took a graduate course in general relativity at Stanford University. There were about 20 guys taking this course. Most of the guys were graduate physics students with only two people being engineers (myself and a classmate that I talked into taking the course), Our instructor issued the first problem set and I did a good imitation of a bug hitting a windshield, i.e. I could not answer a single question in the problem set. I swallowed my pride and went to the instructor to ask for some help, expecting to be laughed at for merely being an aeronautical engineer who was way out of his depth. To my surprise, the instructor was desperate to keep me in his course because only two guys had actually signed up for credit, i.e. myself and the other aeronautical engineer. All those other geniuses were only auditing the course and not taking it for credit. Needless to say, the course was a total blow-out and I had to drop it.

Earlier I said:
“By definition, star ships are huge, massive and complex.”

Pat Galea replied:
“I disagree that this is true by definition. I think it’s probably true as a matter of physics (as far as we understand it at the moment), but there is nothing inherent in the definition of the concept of a star ship that means it must have these attributes.”

Physics defines the problem. You can postulate clicking your heels together three times to get to Alpha Centauri which works fine in fantasy but does work in designing a real spacecraft. A real starship will need to cruise at greater than 1% speed-of-light. If there is any payload at all then we’re talking about an enormous initial amount of fuel to get to that velocity. Unless the fuel is antimatter (not likely), the initial mass fraction of fuel-to-payload will need to be huge. If you want to get dirty with the concept of practical starship design then I recommend reading the Daedalus Project Report by the British Interplanetary Society. Their approach remains the best, i.e. inertial nuclear fusion combined with a magnetic nozzle.

Terraformer said:
‘Of course, it all depends on how fast you’re travelling, what cosmic rays they are (i.e. can they be shielded by a magnetic field), how large the ship is…’

Primary galactic cosmic rays can not be shielded against by a magnetic field with a realistic field strength. To fully shield against galactic cosmic rays you need several meters thickness of material between you and the cosmic ray (ordinary wax is a good shielding material). Having a shield that’s too thin actually makes the problem worse, i.e. the primary cosmic ray hits the shield, shatters into many secondary cosmic rays that then rain down on the payload.

Athena said:
“… biological systems must be seriously considered as an asset rather than an obstacle for interstellar flight. They are resilient, poised for alternative functions, not dead-ended by forced optimization for single goal… and nanobots already function, and have done so extremely well, for millions of years: they’re called enzymes and miRNAs.”

Take your enzymes and miRNAs expose it to a 1000 RADs of radiation and how long does it live? No doubt your snappy come back would be “Deinococcus radiodurans”. However (as you know much better than me) human beings are not a simple bacteria like Deinococcus radiodurans. Could an organism even have a nervous system or go through embryonic development with a metabolism and DNA repair mechanism like Deinococcus radiodurans? I believe it’s less far fetched to download a person’s consciousness to a rad hardened machine versus completely re-engineering a human being’s metabolism and genetic structure. I should emphasize that we’ll almost certainly have passed through “The Singularity” before we’re in an economic position to build a starship. The Singularity will change all the rules concerning how we view consciousness, conscious identity and our relationship with artificial intelligence. More likely than not, human beings will be playing second fiddle to machine intelligence and the starship’s autopilot couldn’t be bothered to bring along a human being even as software stored in memory.

Athena Andreadis January 10, 2010 at 0:15

Gary, radiodurans is only one of the many examples of a biologically resilient system. rRNAs, tRNAs, miRNAs are extremely stable in the absence of water, because they fold into tight high-dimensional structures. Some enzymes are also stable in extreme conditions, and not just those from bacteria either. I can easily envision augmented DNA/chromosome repair mechanisms in a vertebrate and variations have accompanied all specializations for difficult environments (arctic waters, deserts, etc).

The Singularity(at least as envisioned by Kurzweil et al) is a concept of the future and always will be. As I explain in my article Ghost in the Shell: Why Our Brains Will Never Live in the Matrix
(http://hplusmagazine.com/articles/ai/ghost-shell-why-our-brains-will-never-live-matrix) we cannot download a person’s consciousness into any container, carbon, silicon or metal. We can resume this particular conversation after/if you read that article.

Eniac January 10, 2010 at 1:37

George, I think it is impossible to make meaningful predictions as to when an interstellar mission will happen. My guess would be within this century, given the increasingly rapid advances in technology which are making any technological project more feasible by the day.

In my view, the hard physical barriers to interstellar flight will take longer to surmount than the “mere” creative manpower hurdles in the way of autonomous self-replicating machines (autonomous as in, say a lichen or moss growing on a rock, rather than the mean, thinking, fighting machine of science fiction). That is why I think “von Neumann” seeds will be ready to ride on the first non-flyby mission. Given their existence, it would be silly not to send one, since a full-sized outpost capable of growth and replication is so much more useful than what little hardware could be crammed into the payload of an interstellar rocket or sail.

Contrary to popular opinion, I think that such machines will not be “nano” for a long time, as it is much easier to develop and build machines on the scale of, say, toys, than it is on a molecular scale. A “seed” is defined as the minimum amount of hardware that can land on a rocky body, say an asteroid, use starlight to smelt small amounts of raw materials (iron, aluminum, silcon, glass, etc.) from the local dirt, form parts and assemble them to increase its size and capability. In other word(s): grow. It is anybody’s guess how much such a seed must mass, but with suitable miniaturization, a small number of metric tons ought to be sufficient.

Athena: As you say, biological life is an excellent example for an already existing, nano-scale autonomous self-replicating system. It’s seeds are often smaller than the human eye can see. It does, however, have a few flaws for the purpose of space exploration: It does not do well in vacuum, it needs water and carbon, and it cannot easily produce the kind of hardware you need for space travel and communications. Humans are the only lifeforms that can do the first and the latter, but they still need water and carbon. An autonomous system that includes humans will be very large and massive. Only one such exists, it is called the “world economy” and it is so large as to encompass an entire planet. It could probably be miniaturized to the size of a city, but that would be a hard task. We recognize this as the generation ship problem.

Self replicating machines can live on sunlight and rock (oxidized metal and silicon), which are much more widely available in space than water and carbon. They work well in vacuum. They are of the same kind as spaceships and communication systems. If they can build themselves, they can build those, too. They can be miniaturized to reduce the size of a seed. And they do not mind travelling for ten years, or a thousand, because they need to be no more intelligent than a microbe. Once at the target, they can be programmed to build arbitrarily large outposts on rocky planets, moons, or asteroids, with equipment for thorough astronomical observation and high speed communication with Earth. Even fully finished and provisioned habitats for humans that might want to follow. Workers would not be needed, obviously, but researchers and adventurers may want to go.

Perhaps I am blue-eyed about how easy it is to create what amounts to a mechanical form of life, but look at it this way: The simplest of microbes have 1000-2000 genes (see e.g. here: http://news.bbc.co.uk/2/hi/science/nature/4166076.stm), which is a rough equivalent of the number of different parts for a machine. I would wager that a jet airliner or a modern computer chip are no less complex than that. Instead of optimizing a system to propel people through the air at high speed, or to perform billions of calculations per second, we could optimize one to be a versatile parts production and assembly machine. We ought to be able to get it to produce and assemble its own parts as autonomously as that microbe, using a development effort not too far off that of those other two systems.

Adam January 10, 2010 at 4:34

Nice to see you again, Gary. You used to hang out at the “Habitable Zone” didn’t you?

As for starships, personally I think the interstellar matter issue is over-stated.

If we can build self-replicating fabrication machines then, as per Gerald Nordley’s depictions, huge arrays of solar collectors powering beamed-energy projectors will be a better option than huge fusion-pulse drives. But fusion is great inside a star system.

Terraformer (given name = Tobias Holbrook, getting my digital paper trail up) January 10, 2010 at 8:28

“A real starship will need to cruise at greater than 1% speed-of-light. If there is any payload at all then we’re talking about an enormous initial amount of fuel to get to that velocity.”

Or… you could just used beamed power, either solar sail or magbeam. There are ways round the rocket equation, you know.

“Having a shield that’s too thin actually makes the problem worse, i.e. the primary cosmic ray hits the shield, shatters into many secondary cosmic rays that then rain down on the payload.”

Hmmm. But those secondary cosmic rays individually have less energy than the primary ones, right, and are composed of Ions? Which means they’re easier to shield using a magnetic field.

george scaglione January 10, 2010 at 12:44

eniac thank you very much for your well stated opinions on ideas that i and others have stated above.but almost in spite of what i or anyone else may think. i think the real truth follows along with the old saying,lol, “we shall see what we shall see”! thank you very much again your respectful friend george

Terraformer (given name = Tobias Holbrook, getting my digital paper trail up) January 10, 2010 at 14:21

“we shall see what we shall see”

And remember, no news is no news.

Athena Andreadis January 10, 2010 at 14:53

Eniac:

I agree that terrestrial lifeforms are not optimized for space travel for a very simple reason — they (we) all evolved to survive and thrive in the specific circumstances of our planet. I said so in my article series Making Aliens (http://www.starshipreckless.com/blog/?p=24), written lo these many years ago.

I have no ego or money tied up in the primacy of biological means to solve problems on earth or in space, although I get irritated when non-biologists write books and treatises that make them instant futurist gurus despite (or is it because of?) their glaring ignorance of biology. Given what I know, I do think you are blue-eyed. For example, here’s a paragraph that inexplicably uses the present tense:

“Self replicating machines can live on sunlight and rock (oxidized metal and silicon), which are much more widely available in space than water and carbon. They work well in vacuum. They are of the same kind as spaceships and communication systems. If they can build themselves, they can build those, too.”

What non-biological entities presently in existence or near-completion are you referring to? Also, to give one example of a nitty-gritty item, how do you envision these reactions happening in the absence of a solvent?

There is another leap in logic later in the paragraph. “If they can build themselves, they can also build starships.” Using your own arguments, do you see bacteria building starships? Imbuing such (still completely hypothetical) machines with god-like abilities seems to me to be more a wish to overcome obstacles by magic wands, even if they’re nano-sized.

Eniac January 10, 2010 at 15:07

George, you are so right. My current favorite is “If you want to make God laugh, tell him your future plans”, which I have seen attributed to Woody Allen.

daniel January 10, 2010 at 17:57

Gary Allen i wouldn’t call land a probe on mars, science fiction…well this your field engineer, and your doing a great job ,congradulations!

as for me, well i prefer stay with the Physics challenges of exotic propulsion, like on this site: http://captaininterstellar.blogspot.com/

lon below on this site there is a phrase:

“Science community does not address propulsion opportunities, but instead seeks a Theory of Everything. A propulsion focus increases options.”

and

Physics cube, that is the challenge that i go persuade in physics,the challenge of interstellar travel

this unknown of physics will be the answers for the interstellar travel

Gary Allen January 10, 2010 at 20:29

Adam said:
“Nice to see you again, Gary. You used to hang out at the “Habitable Zone” didn’t you?

I did but not anymore (too many crazies and repellent people). Every once in a while I’ll post something at http://www.unmannedspaceflight.com (they’ve done excellent work presenting the progress of the two Mars Exploration Rovers). However I don’t like the prejudice shown at http://www.unmannedspaceflight.com against manned space exploration. I only recently discovered Centauri-Dreams and it appears to be what I had hoped Habitable Zone would become.

Adam also said:
“As for starships, personally I think the interstellar matter issue is over-stated.”

As I see it, there are two basic types of civilizations in the universe:

Type-A: Civilizations that live beyond their planet of origin.
Type-B: Civilizations that die with their planet of origin.

Interstellar travel is the logical follow-on achievement of a Type-A civilization. How is that? Once a civilization can get beyond its planet of origin then eventually there will be commerce between different communities on planets and asteroids. The economic needs of this commerce would bring about a larger and faster interplanetary transportation system. Eventually the industrial infrastructure for making the necessary interplanetary vehicles along with the magnified economic capability would enable the interplanetary civilization to tackle the formidable problem of interstellar travel.

Interstellar travel is first and foremost a problem in economic development.

It is my opinion that single planet economies are incapable of interstellar travel. In my humble opinion, the first step towards the human race developing interstellar travel is to establish a self sufficient colony on Mars. I’ve devoted my career trying to help bring this about. Unfortunately I’m coming to the conclusion that we are a Type-B civilization that just missed at achieving Type-A. My reasoning behind this depressing conclusion gets too far off-topic and I’ll leave that discussion for another day.

Gary Allen January 10, 2010 at 20:41

Athena said:
“rRNAs, tRNAs, miRNAs are extremely stable in the absence of water, because they fold into tight high-dimensional structures.”

I was reading the other day that the notion behind “Jurassic Park” of bringing back dinosaurs through DNA extracted from fossils was nonsense because DNA is an unstable molecule. It was claimed that DNA would break down chemically after a million years. I’ve also read that it has been extremely difficult to obtain viable DNA from Egyptian mummies. I’m generally ignorant about molecular chemistry but these claims seem counter intuitive to me. Supposedly lotus seeds can lay dormant for centuries and bacterial spores can remain viable after 7000 years. I wonder if the expiration date for DNA comes from background radiation?

Eniac January 10, 2010 at 21:19

Athena,

You are right, the present tense was of course not warranted. At the danger of repeating myself, though, I would like to point out that all the processes needed to produce machinery from dirt already exist. We developed them so we could better kill each other and ride around in hunks of metal at great speed. Rock can be reduced into metal, silicon and oxygen in a variety of ways, many without solvents. The production of steel, for example, does not require solvents, as far as I know (carbon, though..). Substituting processes using water or carbon with equivalent ones that don’t will be part of the challenge of adapting Earth-based replicators to the space environment. Perhaps the first will be deployed on the moon, to establish an initially unmanned permanent base.

Since the physical processes all exist, more or less, the development of replicating machines comes down mostly to software, in the field of automation. Automated manufacturing has made great strides in the last century, and I believe we are not far from the point where, given a concerted effort, human labor can be entirely eliminated from the process. I expect this to happen around the time we run out of developing countries providing cheap labor.

No, I do not think bacteria can produce spaceships. That was part of my point. Biological organisms cannot even produce a simple steel bolt, just as no machine canproduce a simple protein molecule, a leaf, or a flower. Mechanical replicators will be made of nuts and bolts. They will be made of the same parts as spaceships and communication systems. By definition, they will be able to assemble themselves from these parts. Assembling those other systems, which are of similar or lower complexity, should not require much extra except for the blueprints.

And no, I do not expect the first mechanical replicators to be nano-sized. We have no idea how to build nano-sized machines, but we have produced regular sized ones for a while, in great variety and copious amounts.

Gary Allen January 10, 2010 at 21:35

Terraformer said:
“But those secondary cosmic rays individually have less energy than the primary ones, right, and are composed of Ions? Which means they’re easier to shield using a magnetic field.”

Your typical cosmic ray starts out in a distant galaxy or supernova as a stripped iron nucleus going 99.99…9% the speed of light in a vacuum. By the time it gets to our galaxy, it’s not an iron nucleus anymore but a stripped helium nucleus due to repeated collisions with interstellar gas. This process is called “ablation”. When a cosmic ray has reached the Earth’s surface, it has experienced many collisions with gas nuclei (a fraction of its original energy level) but can still break any chemical bond. An interesting observation made by the Apollo astronauts traveling to the Moon was experiencing occasional flashes inside their eyeballs. These flashes were Cherenkov radiation due to primary cosmic radiation going through their eye’s vitreous humor. It has been claimed that cosmic radiation is more likely to cause cancer than ordinary radiation like beta rays. I don’t know how this claim can be made since with the exception of the Apollo astronauts we have limit experience with long term exposure of biology to primary cosmic rays. Yes, the astronauts and biology experiments in the ISS are exposed to cosmic rays but those are mainly secondary cosmic rays (the trapped particles in the Earth’s ionosphere provides some shielding). It would be a worthwhile experiment to send a biological sample (e.g. insects, plants, etc) to Mars and back to determine the effect of primary cosmic radiation exposure.

Eniac January 10, 2010 at 21:48

Gary, I don’t know about RNA, but I believe the microbe known as Deinococcus radiodurans is thought to have evolved its astonishing ability to resist radiation damage of its DNA as a defense against desiccation. This would indicate that dehydration and other physical or chemical threats play a larger role in DNA degradation than background radiation.

It is indeed believed that information stored in DNA cannot survive millions of years, but it is known that it can survive tens of thousands, as the successful sequencing of Neanderthal and Woolly Mammoth genomes attest to. Proteins can survive longer, and in work that is, to my knowledge, not yet completely established, a group has claimed to have sequenced collagen molecules from Dinosaur bones.

Protein sequences, though, even if completely known, would not be sufficient to reproduce the organism, as much important regulatory information (promoters, enhancers, and the like) is present only in DNA and not translated into proteins.

On the other hand, it may be possible, given enough modern genome sequences of different species, to track back the evolutionary tree computationally and reconstruct the genome of an ancestral organism. The DNA could then be synthesized, transferred into a chicken or reptilian egg and hatched. There are many caveats, but it is not entirely impossible, I think.

daniel January 10, 2010 at 22:31

Gary Allen yeah in this case look like that you are right. we are the Type-B Civilization,but still too early to give up the mankind still could be a Type-A civilization…i admire your work as engineer to help our Civilization be a Type-A,then lets keep going on this so important job,i will do the same as physicist…

Athena Andreadis January 11, 2010 at 1:07

Gary, DNA and RNA are very different beasties. Non-mRNA is exceedingly stable. Additionally, DNA is not unstable per se. Chromosomes are, because they’re very long — hence fragile. They also carry far more than the protein coding sequences. They contain signals and regulatory sequences for chromosome folding, recombination, replication, transcription, splicing and translation (which is why just decoding the genome sequence was closer to the kids who chant Hebrew in their bar/bat mitzvahs without knowing what the words mean). The compression and amount of information is amazing. As I said in my book, it’s like having a single text that can be read in Russian, Mandarin, Navajo, Maori, Quechua and Swahili.

Dinosaur DNA might survive in pieces (as it did for mammoths, Neanderthals, Ötzi and many mummies), but not the entire intact genome that would allow 100% reconstruction. We can (and do) extract and reconstruct genes from any sample that has even minute amounts of either RNA or DNA by PCR — I’m a crack cloner myself, I can amplify just about anything. The major problem is not radiation, especially not the feeble 4 K background radiation, but the natural slow decay of the tissue, which causes degradation because nucleases remain active in the cells after an organism dies.

Ronald January 11, 2010 at 4:30

Gary,

we may not entirely agree on the value of M dwarfs for (living) planets ;-), but I am entirely with you on the paramount importance of interstellar travel.

“As I see it, there are two basic types of civilizations in the universe:
Type-A: Civilizations that live beyond their planet of origin.
Type-B: Civilizations that die with their planet of origin.”
“the first step towards the human race developing interstellar travel is to establish a self sufficient colony on Mars”.

I could not agree more.

Gary Allen January 11, 2010 at 4:30

Athena said:
“The Singularity(at least as envisioned by Kurzweil et al) is a concept of the future and always will be. As I explain in my article Ghost in the Shell: Why Our Brains Will Never Live in the Matrix … we cannot download a person’s consciousness into any container, carbon, silicon or metal. We can resume this particular conversation after/if you read that article.”

I read your article with interest and find that you’re a very good writer. Your thoughts on the topic of artificial intelligence parallel many of my own.

You mentioned John Searle’s “Chinese room argument”. A million years ago when I was an undergraduate at U.C. Berkeley, I took one of John Searle’s philosophy courses. Back in those days, I still thought philosophy was useful and studied the subject extensively. I now believe that philosophers are good at asking questions and criticizing other people’s answers but less good at providing useful answers. It’s possible (or even fashionable) for a philosopher to say something stupid like “There are no absolute truths” and not realize that he’s an idiot for saying this. I’ve since concluded that the study of science, mathematics and history (particularly ancient history) are far more useful activities than philosophy.

I believe the main difference between human behavior and animal behavior is that a significant fraction (most) of animal behavior is hard wired by genetic information (instinct) while human behavior is mostly learned. I suspect that the top level (learned) algorithms driving human behavior, consciousness or intelligence are ultimately rooted to a very simple algorithm that is hard wired by genetics. To make my point, I’m forced to commit the fallacy of arguing by analogy and provide the following link:

http://en.wikipedia.org/wiki/Gun_(cellular_automaton)

Note that the “Gosper Glider Gun” is fairly complicated and can have many configurations but the underlaying algorithm of Conway’s Game of Life is utterly trivial. I believe a similar process drives human behavior, i.e. human consciousness is driven by some trivial algorithm controlling the transfer of information at the neuron level. I suspect the best way to discover this trivial algorithm is through simulation of brain neuron networks in a computer network. Assuming the computer network modeling the simulation is big enough then it should “wake up” and become conscious provided the correct root algorithm was programmed in. After the computer network wakes up, then the real work would begin to teach the machine to do something other than cry for its mother.

This thread has grown too large so I’ll add no more comments to it.

Adam January 11, 2010 at 6:00

Hi Gary

DNA is chemically/structurally different to RNA – eg. a double helix vs a single. Also in organisms that undergo suspended animation they ‘lock’ their biomolecules in place with complex sugars or some other polymer. Otherwise hydrolysis causes molecules like DNA to slowly scramble over time. Background radiation might have something to do with extremely long term viability, but I don’t think anyone has investigated that.

FYI on average in a 70 kg human body – eg. lean human male – there’s about 15,000 radioactive decays per second, mostly from K40 and C14 decay. There’s a very tiny amount of U, Th, but they contribute only a tiny fraction, a few decays per second. The rest of the normal dosage is cosmic-ray secondaries, plus stuff like radon, natural radioactivity in granites etc. So the internal sources of radioactivity are low and the background flux is probably the major source of exposure. Unless you’re unlucky enough to get hit by a gamma-ray beam from lightning – apparently it’s quite strong. If bacteria are lofted into the very upper atmosphere there’ll be exposure to cosmics and gamma-radiation from upper atmospheric lightning phenomena like sprites.

Terraformer (a.k.a Tobias Holbrook) January 11, 2010 at 15:58

We could always use life as our self replicating machines. If – when – our capabilties reach the point when we can construct true Dyson trees, we could send a packet to a target star system, where at least one would be lucky enough to land on a comet (assuming we send loads). Then that one will proceed to seed the rest of the comets with life. When humans arrive, they’ll find a ready made habitat for them, with everything they need. If they want to, they can convert the smaller trees into starships.

I believe the future of technology lies in biology, which is why I intend to work in that field.

Athena Andreadis January 11, 2010 at 17:03

The future of technology will be mixed, with biology a prominent component (if we want to succeed). Dyson trees, however, at least as described by Dyson, are as possible as attaining individual immortality by uploading. Trees are pretty extraordinary — but photosynthesizing in interstellar vacuum is not within their blueprint specifications.

Eniac January 11, 2010 at 19:30

“We could always use life as our self replicating machines”

Well, self-replicating machines are life, by most definitions. The issue is which kind of life is better suited to a) make the trip b) perform astronomical observations and c) send back the data.

True, “traditional” life has the huge advantage that it already exists. However, it loses out pretty big on all the other fronts. How do you create an organism that can travel and send signals over interstellar distances? We have NO idea. I do not claim it is easy to create mechanical life, but I do think it is possible, and inevitable in this century, perhaps even early on. It is certainly more feasible than interstellar trees, and, I believe, more feasible than interstellar travel itself.

For those who have an interest in the matter, and have not yet done so, read or browse “Kinematic Self-Replicating Machines” by Robert A. Freitas Jr. and Ralph C. Merkle, available on-line here: http://www.molecularassembler.com/KSRM.htm. It is one of the few recent works in this area, and gives an exhaustive overview over this fascinating, yet curiously neglected subject. I think the problem with the field is that everyone hopped onto the nanotech bandwagon, leaving practically noone working on the much more tractable kinematic problem.

george scaglione January 13, 2010 at 11:36

hello everyone as regards some of the above let me add,john lennon ,”life is what happens while your busy making other plans” – he was was soooo right! respectfully your friend george

george scaglione January 17, 2010 at 13:43

i have to make a correction please…above i said that imho the first interstellar spacecraft,not necisarily any great shakes by the way would happen around 2075.sorry,i meant 2175!! 2075 when i typed it was probably just wishful thinking! regards your friend george

Eniac January 17, 2010 at 16:12

Just a little appendix on ancient DNA reconstruction and the Jurassic Park scenario:

I think it is pretty clear that ancestral genomes could be reconstructed, exactly, using computational phylogenetic reconstruction. See, for example, the article referenced below. However, that will not give you T. Rex, only its most recent ancestor common with some other species, living or recently extinct, that can be sequenced. The closest living relatives of the Dinosaurs are birds, but AFAIK none are directly descended from the Dinosaurs we are familiar with. Thus, the result of such reconstruction could be disappointing. More like a chicken than a ferocious giant carnivore, perhaps. Real and good enough for science, but not so good for a theme park.

You may be able to work your way fairly close to a T. Rex, though, by adding in any fossil protein sequences you can get, and perhaps some creative genetic engineering guided by the phenotypic fossil evidence. Such creative engineering, while good for theme parks, might not be so good for science, though.

Ancestral animal genomes reconstruction
Virginie Lopez Rascola, Pierre Pontarottia and Anthony Levasseura, Current Opinion in Immunology
Volume 19, Issue 5, October 2007, Pages 542-546

Reconstructing the evolutionary history of all species is an essential objective for evolutionary biologists. Much effort has been devoted to ancestral genome reconstruction. Numbered genome sequencing of current and extinct organisms enables evolutionary biologists to compare genomic data and reconstruct ancestral genomes. Long-term conservation of karyotype, gene order or gene sequence are clues to the heritage of each species and these data can be used by evolutionary biologists to synthesize distant ancestral genomes. In this review, we referred to the recent advances in ancestral genomes reconstruction and the insight it gives on genome evolution. Special attention is devoted to the use of this knowledge to understand the evolution of the immune system genes.

ljk January 26, 2010 at 14:15

Numerical Testing of The Rare Earth Hypothesis using Monte Carlo Realisation Techniques

Authors: Duncan H. Forgan (1), Ken Rice (1) ((1) SUPA, Institute for Astronomy, University of Edinburgh)

(Submitted on 11 Jan 2010)

Abstract: The Search for Extraterrestrial Intelligence (SETI) has thus far failed to provide a convincing detection of intelligent life. In the wake of this null signal, many “contact pessimistic” hypotheses have been formulated, the most famous of which is the Rare Earth Hypothesis. It postulates that although terrestrial planets may be common, the exact environmental conditions that Earth enjoys are rare, perhaps unique. As a result, simple microbial life may be common, but complex metazoans (and hence intelligence) will be rare. This paper uses Monte Carlo Realisation Techniques to investigate the Rare Earth Hypothesis, in particular the environmental criteria considered imperative to the existence of intelligence on Earth.

By comparing with a less restrictive, more optimistic hypothesis, the data indicates that if the Rare Earth hypothesis is correct, intelligent civilisation will indeed be relatively rare. Studying the separations of pairs of civilisations shows that most intelligent civilisation pairs (ICPs) are unconnected: that is, they will not be able to exchange signals at lightspeed in the limited time that both are extant. However, the few ICPs that are connected are strongly connected, being able to participate in numerous exchanges of signals. This may provide encouragement for SETI researchers: although the Rare Earth Hypothesis is in general a contact-pessimistic hypothesis, it may be a “soft” or “exclusive” hypothesis, i.e. it may contain facets that are latently contact-optimistic.

Comments:
13 pages, 10 figures, accepted for publication in the International Journal of Astrobiology

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Galaxy Astrophysics (astro-ph.GA)

Cite as: arXiv:1001.1680v1 [astro-ph.EP]

Submission history

From: Duncan Forgan [view email]

[v1] Mon, 11 Jan 2010 15:53:09 GMT (164kb)

http://arxiv.org/abs/1001.1680

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