I had blogged a while ago, about the Vatican astronomer who was seriously confused about extraterrestrial life.

Well evidently, I must not have been the only one concerned, because Pope Benedict XVI just held a Pontifical Academies conference on astrobiology, which Fr. Funes organized. It isn't the conference I would have organized, though I did know two of the invited speakers. Evidently the reigning paradigm is that Darwinian evolution is just so efficient that there must be life out there, so merely finding a giant gas planet in another solar system is reason to start humming the theme song to Star Trek.

As my earlier blog alluded, I'm of the opinion that life is both more common and more common. It doesn't just live on rocky planets around G-type stars, but populates all star systems that have a cometary cloud, be they blue giants or red dwarfs with or without planets. However, most of this life is manifestly common, the blue-green algae that make pond-scum and the viral bacteriophages that infect them. Somewhere in our galaxy there may exist an ocean full of trilobites, and perhaps, just a very weak perhaps, some reptiles. But it is highly unlikely that there are mammals anywhere else in the galaxy and a foregone conclusion there isn't another sentient primate.

How do I come to these conclusions? By studying the information content of evolutionary "steps" and the necessary planetary bootstrapping that permits their existence. The reason for the difficulty of higher life forms, is not their difficulty of information content, but the necessity of preparing a place for them. Should one be able to program into a computer model all the necessities of a self-sustaining biosphere and the processes that produce it, and given a black rock for a starting point, I would venture a wild guess that 4 billion years is the earliest scenario that would work, with many others taking 10's of billions of years longer.

Let's approach this from another viewpoint. Suppose the USA wanted to terraform Mars to make it useful as a resort community for retired presidents. How many missions would it take, and in what timescale would it be ready to start collecting tourist dollars? An Ares-V mission every month for 10 years? for 50 years?

Now suppose that NASA has discovered a really efficient solar-sail technology to get to Mars, only it can only transport 1000 kilograms (metric ton) every two years. How long would it take to terraform Mars, assuming that on the first trip we could land a few astronauts, a nuclear reactor and terrarium for growing food? 50 years? 100 years?

Now assume that NASA invented something even better to resupply Mars, a way to move 10 kilos every day, the Mars Advanced Transporter, only the 10 kilos has to be divided into separate 100 milligram packages, 100,000 packets a day. Could we imagine terraforming Mars with that? But this is essentially what comets provided for Earth. So if you can solve NASA's MAT puzzle, you are well on your way to understanding the 4 billion year delay terraforming of Earth.

I think the answer lies in sending the information, without the machinery. That is, we send the DNA via bacteriophages, with some useful cynaobacteria for provisions, and inject the DNA into Earth precursors to produce the next big step of evolution.

So the question that consumes Fr Funes, about whether extra-terrestrial intelligence exists, comes down to the teleology of multiply terraformed Earth's out there. In order to get Earth to where it is today, do we need backups? Only if you think you're going to fail to bootstrap Earth. I mean, do you boot two computers on your desk every morning for fear that one won't boot?

No, I didn't think so.  So why would there be any need for another planet in the galaxy with life on it? Perhaps as a staging ground for this cometary bootstrap process. So the question comes down to, how much staging does a terraforming require? Let me explain.

Suppose we needed to introduce trilobites to Earth in order to prevent our recently booted foraminifers from sequestering all the CO2 at the bottom of the ocean, destroying the oxygen atmosphere and killing off all the animals we had so carefully booted. Can we fit a trilobite in a 100 mg packet? No. And suppose we don't have any trilobite precursors on Earth whose DNA we could tweak with some horizontal gene transfer virus. What do we do then?

We would need to divide up the chromosome of trilobites into transportable packets, say, bacteriophages, and reassemble them on Earth. But what is the likelihood that they would reassemble, especially when diluted in the Earth's oceans? Not very good. But if we could deluge the Earth with enough DNA, perhaps it could be done. In that case, we need a staging ground for the DoS attack, and hence a planetesimal or comet just chock full of DNA, say, in living trilobites.

(Well if we can put trilobites on comets, why not transport them whole to Earth? Because the problems of high-speed impact, as well as hostile environments for lengthy interstellar transport, including the food problem.)

What we're talking about here, is the problem of the Cambrian explosion of lifeforms some 550 million years ago. After that point, we don't need to transfer whole organisms, we can just keep inserting genes into existing organisms and make them bigger. But the total lack of big critters in the Pre-Cambrian looks as if entire animals show up miraculously on Earth.

So there might be staging grounds for the Pre-Cambrian critters--planets where all the pieces have been developed for transport. This is why I don't rule out the extra-terrestrial discovery  some lower life forms, but would rule out the discovery of higher life forms.

Why wouldn't the same bootstrap process occurring at Earth also occur in distant solar systems? We alluded to the answer earlier, it is possible, of course, but it is like asking why couldn't there be two computers on your desktop booting up in the morning? Why not three or four? Because it would be redundant. If you know what you have to do on your computer, and are sure it is failsafe, you don't need and can't use several computers simultaneously. Far better to get a dual, or quad-core computer than two entire systems using up deskspace. Similarly, if the Earth is the place for Man, why would it be necessary to have two?

Let me be blunt. If the Earth is designed as a bootstrap world for the enjoyment of Man, then there is only need for multiple worlds if there is a fear that the bootstrap would fail. You know what I'm talking about. I'll bet you only began to back up your data after you had a major hard drive crash. But if you have never experienced such a data loss, you don't think redundancy is worth Limbaugh's "carbonite" no matter how often he flogs it. So if the Designer doesn't expect to fail, why the need for redundancy? (Maybe Fr Funes can explain that one.)

Having eliminated redundancy from the design, then we should look for necessity. If comets are the delivery vehicles, how would such a bootstrapped system be staged? Should we look for worlds full of dinosaurs, trilobites, or just pond-scum?   The romantic part of me hopes for "Lost Worlds" but the realist part of me expects pond-scum.

Maybe that's why they didn't invite me to the Pontifical Institute.