Your probe idea has been explored by the series Lexx (http://en.wikipedia.org/wiki/Lexx)

Unfortunately I cant remember the plot, but the growthrate of the probes got out of control and they did indeed attempt to consume all the resources in the galaxy. (citation needed)

I’ve long thought that the way to conquer this problem, is to create a fully automated, self-replicating probe. They would need some kind of system to share data (thus allowing information to propagate back and forth as they travel). You would also need a growth control mechanism to stop them from overwhelming galaxies and consuming all available resources.

The idea is that you have inevitable losses as the probes travel. It doesn’t matter in totality however, because there’s a fleet of them and some level of losses are acceptable. They spread in a random fashion and thus some always return “home”. Every probe is built to have curiosity about every other probe, so if they are in proximity, they meet and share data.

The real hard problem, I suspect, is that you might have probe evolution happening over long periods of time. They might divergently evolve and become unable to interface with each other. Also, they might start to require data storage, communications, fuel, or operational lifetime needs that far outstrip the original design. Ergo, probe evolution might be an operational necessity!

It would take a visionary development project to create. The effort would take millions of years to even begin to pay off. However once you create the original batch of probes, they take the work from there on.

I’ve got a feeling someone has written a sci-fi story along these lines already (Star Trek: TMP doesn’t really count as V’ger was a one-off).

Awesome, thanks for the info.

The whole methane on Marsh thing is IMO on of the most exciting questions in science at the moment. It would have been a let down if this was the answer…

IIUC, chloromethane and DCM are products of chloride radicals reacting with hydrocarbons or other organic molecules. The chlorine – carbon bond is pretty strong, making for some quite stable compounds.

By way of comparison, chlorocarbons and CFCs on Earth are very long-lasting (for all practical purposes, they are inert in the lab) until they reach the upper atmosphere, where they are photolysed by UV.

Slightly off topic here, and I’m not a chemist, but it occurs to me to wonder if, given that perchlorate is such a powerful oxidizer and so reactive, if it is abundant enough, could it be used as a source of fuel/energy

IIUC, perchlorate is more stable than molecular oxygen, so is therefore a less useful oxidiser. It’ll also be heavier because of the chlorine.

So what is the sequence of preadaptions/mutations that lead to technological intelligence?

Broadly, the following are necessary:
Ability to plan;
Ability to cooperate;
Ability to communicate;
Ability to manipulate;
Ability to remember / learn.

How many different ones are there (is the path that led to humans on earth the only way or not)?

We have no idea. In fact, we may not have much of an idea about how to begin to answer that question.

How likely are these events to occur?

Independently, they are not all that unlikely – we see many examples in species on Earth (Chimps, dolphins, Caledonian crows etc.).

Taken together, however, we have only one example so we can’t comment about likelihood or otherwise.

What are the environmental conditions in which these adaptions likely to be favored and preserved by natural selection and how commonly do they occur?

Don’t overlook the possibility that there may be multiple possible combinations that favour these kinds of adaptation.

Are there conversely environmental conditions in which intelligence/preintelligence might actually be disadvantageous and be selected against, and how likely are they to occur?

Well, the large brain comes at a large cost.

If you take humanity’s other compromises and adaptations, we’re quite ill-suited to surviving when separated from our communities, so if a disease were to wipe out most of humanity then it might be difficult for the survivors to maintain our position as the dominant vertebrate on Earth.

But that’s just speculation, really.

And all of course, on a per planet basis.

We can’t say anything intelligible about probability until we know the answers to these questions, and we can’t actually know without finding another intelligent technological civilization.

Broadly, I agree.

The development of intelligent, social apes able to manipulate tools and plan cooperatively is an historical accident on Earth, and we have little idea of how it came about.

It does seem likely that a species that develops technology will have an advantage over species that do not. So while not inevitable, technology is likely.

This looks like a non-sequitur to me.

Assuming techology in general gives a species as a whole an advantage, then whenever such technology arises, its use will spread through the population.

However, this tells us nothing about how likely it is for a technological society to arise in the first place.

For instance, tehcnology requires that the developers have big brains, and big brains come at a huge cost in energy, so a perfectly reasonable argument can be made against it being likely. Ultimately, we just don’t know. Our sample size is 1.

Neither the evolution of a species capable of developing technology, nor the actual development of that technology once such a species has evolved, are certain, or even particularly likely.

While I agree with the general principles in the rest of this particular post, I must point out that trying to use any probabilistic arguments with our current state of knowledge is actually not valid.

The point is “[+/-not] particularly likely” with respect to what? What is the denominator of your (Technological Intelligence)/N for your probability assessment? All the data we can muster by studying life on earth and human history can only apply to N as number of species. And of course we know that this probability is very low.

But for the question of extraterrestrial technological intelligences, we need to know what N is for number of planets. Any planet with an earth-like biosphere should be expected to produce trillions and trillions of species occupying trillions and trillions of every-changing niches over a habitable lifespan of several billion years. So even if the likelihood of intelligence per species is minutely low, from the point of view of the lifespan of an entire planetary biosphere, the probability could still easily approach unity (or not – all we can say is that our current experience is 1/1.)

So what is the sequence of preadaptions/mutations that lead to technological intelligence? How many different ones are there (is the path that led to humans on earth the only way or not)? How likely are these events to occur? What are the environmental conditions in which these adaptions likely to be favored and preserved by natural selection and how commonly do they occur? Are there conversely environmental conditions in which intelligence/preintelligence might actually be disadvantageous and be selected against, and how likely are they to occur? And all of course, on a per planet basis.

We can’t say anything intelligible about probability until we know the answers to these questions, and we can’t actually know without finding another intelligent technological civilization.

Even finding primitive life elsewhere in our solar system won’t actually provide useful information for this probability assessment. Because if we do so, we might expect that many solar systems ought to have many worlds with conditions similar to places like Europa, Enceledas, Titan, and Mars, where life might arise but the habitability period of the world is too short, or the environments too marginal, to allow for the development of complex intelligent life, but we won’t be able to discern from that evidence alone, how likely a planet like earth (“like” earth in the sense that it is capable of producing and supporting an intelligent lifeform, rather than strictly similar to earth in environment/history/etc, as we don’t actually know how many different types of planetary environments/histories are actually capable of supporting the development of an intelligent lifeform) is, per solar system.

The denominator issue just changes from N planets to N solar systems.

Basically, no rigorous probability argument of any kind, for or against, can be made without finding at least one other technological civilization. Doesn’t mean we shouldn’t try to make such arguments, since the process generates useful information and questions, but we need to always be cognizant of the limitations inherent in the exercise.

While it is certainly plausible if not likely that they would be interested in planets like earth scientifically, such an interest would in fact motivate them to be discrete – they would spend most of their effort observing us with telescopes, and what expeditions they do send for direct visitations would be expected to be small and well hidden.

Which brings up the question that if such activity were occuring in the Oort Cloud or Kuiper belt or therearounds, how likely would we be to detect it with our currently available astronomical techniques and instruments?

Joking aside, I think Mars has a lot more to say. Missions to Mars excite the crap out of me. I really loved watching the coverage of Phoenix landing a couple of years ago. Hearing the speeds, altitudes and various key events. That was one happening control room. It was by far more exciting than any sporting event (save game 7 of the 1992 NLCS Braves vs. Pirates )

I could watch space stuff all day!

@c travel time is 75,000 years
@0.001c travel time is 75,000,000 years
@voyager speed (~16km/s) travel time is 1,395,000,000 years

These would be the best rate numbers to fill the galaxy – assuming negligible failure rates for the probes. Regardless of the replication rate, you still have travel time. These are the numbers for average velocity and assume the time to build new probes at each new system is insignificant compared to travel time.

Travel time to the Andromeda Galaxy
@c travel time is 2,500,000 years
@0.001c travel time is 2,500,000,000 years
@voyager speed travel time is 46,500,000,000 years
That’s just to get there.

A necessary, but not sufficient, condition for the rise of intelligence and hence technology is encephalization. There is evidence for a selection advantage for encephalization from the fact that the Cretaceous dinosaurs were more encephalized then their Jurassic forebears and that todays’ mammals are more encephalized then the mammals of 50 million years ago.

Any realistic growth rates, assuming some kind of interstellar transportation (even if it never makes better than 1/1000th of c) results in galaxies filled in a few million years, and the next galaxy over shortly there after.

First, however, you have to have the raw materials, no matter how intelligent your species.

Then you have to survive.

We may be one of the first. There is no paradox.

Finally, we may not survive long enough to be first, either.

Granted, neither sentience nor technology are the “point” of evolution, they’re just patterns of mass/energy that happen to be successful at sustaining themselves.

I believe it was the Greek Hero who built the first steam engine(ok, it was a ball of copper, heated over an open fire, that spun from steam vents). Unfortunately, it was the Greek ideal of intellect being superior to experimentation that guaranteed his experimentalist approach would not be acceptable to his fellows. There is a bias in the middle east toward getting ones hands dirty(experimental, actually building something), as in “Gentlemen don’t work for a living. They just provide supervision.” Romans weren’t so restricted, thus they became known as the builders of roads but they weren’t particularly oriented toward a theoretical understanding of processes. It took another millennium for someone(a Sufi mystic in Persia), to delineate the scientific method, which combined those two disparate approaches to knowledge. It took another half millennium for the law(as in protection of intellectual property rights) to allow individual inventors to profit from their labor. THAT’S when the industrial revolution took off. We had to get so many different things right before we could get a techno. civilization off the ground, I’m occasionally amazed we managed to do it at all.

So, yeah, there may be a lot of intelligent, sophisticated species out there that just never managed to get all those ducks lined up.

Gary 7

the process toward a technological civilization is also slow due to having to restart periodically.

Umm, no. Technological civilisation is not the “target” of evolution. Before we came along, life on Earth was not progressing towards anything – it was just muddling along (as it still is). If it wasn’t for those mass extinctions, we’d still have one of the previous stable ecosystems which did not feature technological civilisation.

Then there’s the fact that we’ve been around in our current form for a very long time, but only developed our current technological civilisation recently. The ancient Greeks (or many others) could have developed all of the technology needed for the Industrial Revolution, but they didn’t.

Neither the evolution of a species capable of developing technology, nor the actual development of that technology once such a species has evolved, are certain, or even particularly likely.

To put it in terms of the Drake equation, both f_i and f_c are probably quite a lot smaller than 1. It quite possible that L isn’t very big either.

Don’t forget the military input into Shuttle’s specifications. Had it been left as a small launch vehicle rather than the monster it became, it may not have needed the ET and the SRBs.

Of course, it would not then have been able to launch missions like Hubble, so there may have been more resistance to the orbiting observatories.

Phil, as I read it, it is not that it is “not likely” to find organics where perchlorates “are hanging out”. The perchlorate doesn’t react spontaneously with the organics. Rather, it was (hypothetically) the specific Viking experiment itself that caused the perchlorate to react and thus destroy the organics when it heated the soil and its perchlorate/organics content.

MSL will have other ways to examine the soil in which this destructive reaction should not occur. This means that it is now fair to expect that MSL will find organics – they are not necessarily as rare on the surface as has been thought for 30 years.

Chemistry still happens at low temperatures – the reactions between perchlorate and whatever organics there are will still occur at -20 or -40 °C but will be orders of magnitude slower than in the Viking expt. However, the products of that chemistry might be different, for reasons that I can’t think of a way to share in less than three paragraphs.

Sadly I’m forced to agree with your statements in regards to the Shuttle. It is (was? well, soon enough we can refer to it past tense) the most complicated piece of technology ever built… sadly, most of that was overkill. It was not at all the vehicle we needed to construct a working infrastructure in Earth orbit. Complexity sometimes just means more things to go wrong.. and simple and stupid is sometimes the most effective tool for the job.

The shuttle was a poor compromise between scientists and politicians – Congress demanded a reusable vehicle, so NASA delivered.. despite the fact that mostly un-recyclable vehicles could have done the jobs needed cheaper, and had the advantage of being able to adapt the design for those vehicles as technology improved and the tasks needed evolved.
But it’s difficult to convince a politician that it’s cheaper and more effective to burn many tons of steel in the atmosphere than it is to build a reusable ship.