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081 - Steam

El Cid

on June 22, 2016

Oh man, that shower took forEVER! Seems like she's been in there since Monday!

I was going to do a two-page spread of Ozzy showering next. But then I decided not to. Because it was not a good idea.

And also, I wasn't planning on doing another super-long science blurb today, but this ties in with the “Know Your Neighborhood” interstellar stuff I've been posting the last few updates. It's my own (likely very misguided) blueprint for how we could colonize the galaxy without using any technology that isn't at least theoretically on the horizon for us in the not-too-distant future. It's not necessarily canonical to the comic, however.

Feel free to skip ahead to the Comments section if you're not in a reading mood. This blurb is even nerdier than my usual.



Space travel is hard, and that's just talking about travel within our solar system. Interstellar travel is exponentially more demanding; in fact, some of the world's best rocket scientists believe it will never happen. This was the conclusion of the 2008 Joint Propulsion Conference. It's not even entirely an engineering issue. We do have spaceship designs like Project Daedalus and others that theoretically could get us there if we built them, but there's still no dodging the cold unforgiving math of interstellar travel. In order to accelerate a craft the size of the space shuttle to 10 percent of light speed would require over 250,000 terawatt hours of energy, which is way over the annual energy consumption for the entire Earth population. And that assumes your propulsion system is perfectly efficient (which is impossible) and ignores the energy you'd need to keep a crew alive for the forty-plus years it takes to reach the nearest star.

So there's no hope then, right? Well, not so fast. While it's absurd to realistically think about sending large spacecraft with human crews on an interstellar voyage, it's completely feasible to send very small probes. Using current or very near-future propulsion technology, it seems entirely plausible that we could launch craft ranging from tiny nano-size all the way up to a kilogram, on their way to the stars. Stephen Hawking and a gaggle of other supergeniuses are working on a project to zap gram-scale nanocrafts into space at 20 percent the speed of light using lasers and tiny light sails. There are even more promising developments in the offing, like the nanoFET (field extraction thruster) propulsion system, which can accelerate to very high speeds by emitting charged nano particles at nearly the speed of light.



So big hairy deal, what good does it do sending little probes to the stars? Well, in the last two science blurbs, I already alluded to one scenario. If you can get the little probes to a new star system, then they can gather local materials and use them to build duplicates of themselves. And then once you have enough little robots, they can build bigger robots, and then the bigger robots can build… well, they can build pretty much anything. They can build power generators, they can build communications arrays capable of sending and receiving communications from Earth, they can build laboratories for cooking up synthetic life from the amino acids which seem to form readily in comets.



That last part is probably the most controversial. We don't know for sure how easy it is to synthesize life from raw components, or if those components are as readily available in other stellar systems as they are in the outskirts of our own. But assuming that the genesis of life is something other than magic, it at least sounds plausible. Barely.

And so that's where your interstellar colonists come from. You don't fly them there in big heavy starships. You grow them, from tiny little nano seeds, spread to the cosmos like pollen in the wind. One problem you get with seed people though, is that being grown in a lab and raised by robots may leave you with a colony of psychotics unfit, unable, or unwilling to survive and propagate. In the science fiction world of this comic at least, the solution is for the first generation to emerge fully grown and imprinted with the personalities of real people from the solar system, or possibly with fake personalities and memories crafted by the nano assemblers. I guess they'd never know the difference either way!



Okay, so big whoop! Assuming we clear a few technological hurdles, that means we maybe could launch probes at a measly 20 percent light speed or so and set up little “shake and bake” colonies around nearby stars. 20 percent light speed is still super slow on a galactic scale, isn't it?

Well, assuming we wanted to colonize the entire galaxy, and we launched our self-replicating probes at .2 light speed, how long would it take them to populate the whole Milky Way? By our latest estimate, the Milky Way is 160,000 light years across, so it would take 800,000 years for probes to reach from one end to the other. So if the galaxy is 12.6 billion years old, that means we would have had time to cover the whole thing 15,750 times over the course of its lifetime. So it's far from a futile effort!