Skip to content. | Skip to navigation


I've made my first novel, Ventus, available as a free download, as well as excerpts from two of the Virga books.  I am looking forward to putting up a number of short stories in the near future.

Complete novel:  Ventus


To celebrate the August, 2007 publication of Queen of Candesce, I decided to re-release my first novel as an eBook. You can download it from this page. Ventus was first published by Tor Books in 2000, and and you can still buy it; to everyone who would just like to sample my work, I hope you enjoy this version.

I've released this book under a Creative Commons license, which means you can read it and distribute it freely, but not make derivative works or sell it.

Book Excerpts:  Sun of Suns and Pirate Sun

I've made large tracts of these two Virga books available.  If you want to find out what the Virga universe is all about, you can check it out here:

Major Foresight Project:  Crisis in Zefra

In spring 2005, the Directorate of Land Strategic Concepts of National Defense Canada (that is to say, the army) hired me to write a dramatized future military scenario.  The book-length work, Crisis in Zefra, was set in a mythical African city-state, about 20 years in the future, and concerned a group of Canadian peacekeepers who are trying to ready the city for its first democratic vote while fighting an insurgency.  The project ran to 27,000 words and was published by the army as a bound paperback book.

If you'd like to read Crisis in Zefra, you can download it in PDF form.

Personal tools

Colonizing Alpha-Centauri: the least and most we can do

Filed Under:

There is at least one planet. Therefore, colonization is on the table

Yesterday it was announced that an earth-sized planet has been discovered circling the nearest star, Alpha-Centauri (around the smaller of its two main stars, actually, Alpha-Centauri B). The planet, Bb as it's currently called, has a six-day year and a surface temperature of 1500C. Not very hospitable, perhaps--but I'm about to argue that it's just fine. If we can get to this star system, we can settle it.

Let's look at two scenarios, a worst-case and a best-case, and see what's possible with each.

The Worst Case

This is a boiling hot planet. Actually, far hotter than boiling. At 1500 degrees, it's hot enough to melt rock. In a worst-case scenario, Bb has the kind of rotational resonance that Mercury does: it is not fixed with one face pointed forever at its star, like our Moon is to the Earth, but rotates so that the whole planet is regularly bathed in the blowtorch heat of the star. If there is an atmosphere, it's mostly composed of evaporated rock.

In this case, much or all of Bb's surface is a lava sea. Oh, and since this is a worst-case scenario, let's say that there are no other planets in the system, not even any asteroids. Bb is it.

If your idea of habitability is finding a more or less exact copy of the Earth and settling down on it to farm, then things are looking kinda bleak. But, if we have the technology to get to Bb, then we have the technology to live and thrive there.

Not on the surface, of course. Not even in a nearby orbit. But even if Bb is uninhabitable, it is still a great source of building material. If we have the technology to get to it, we'll have the technology to mine it, if only by dangling a skyhook down from the L2 point (or from a heliostat) to dredge the magma ocean. Haul the magma up, render it in the terrible light of the star, and ship the refined goods to a higher orbit where the temperature's a bit better. There, we can build habitats--either O'Neill colonies or, if we can harvest enough material, the coronals I describe in my novel Lady of Mazes.

With unlimited energy and (nearly) unlimited building materials, we can construct a thriving civilization around Alpha Centauri B, even if all we have to work with is this one piece of melted rock. (In terms of details, it would be a bootstrapping operation, with an initial small seed of robot miners constructing more or bigger skyhooks, more miners, etc. until exponential growth sets in, by which time it's safe for the human colonists to show up.)

The Best Case

 Even for the best case scenario, I'm going to assume that Bb is the only planet in the system. It's more likely than not that Bb actually will be tidally locked to its star--i.e., it has one face permanently aimed at its sun, and the other permanently in darkness. The point that's under a permanent noon (the 'solar pole') will indeed be a lava hell. What's interesting, though, is that some simulations show that the temperature in the twilight zone around the 'equator' and further into the night side could be quite cool. Cold, even, if you go far enough. If there's an atmosphere, there might be water and a zone of permanent rain around the mid-latitudes of the dark side, in a kind of hemisphere-wide hurricane with its eye at the anti-solar pole. And there, we might settle.

I doubt there'd be any oxygen to speak of, but we can generate that ourselves. What I find interesting, though, is that this 'dark side' is not really dark at all. Because Alpha Centauri is a binary star system, Centauri A will be visible in the 'night' sky of Bb during half its year. ...Which is only three days long. So A will cross the sky in about 75 hours, and then there'll be true night for 75 hours. This has been the pattern on Bb now for more than four billion years; it's pretty stable.

Centauri A appears very dim from Bb compared to our sun, but it's still too bright to look at and has a visible disk. It's dimmer than daylight, but much, much stronger than Earthly moonlight. Granted the luminosity range at which photosynthesis happens on Earth, I'd think plant life would do quite well on Bb's 'dark' side.

If the rain's not too bad, much of the 'dark' hemisphere might be settled. Remember that Earth is mostly covered with water; if there's no significant oceans on Bb, but enough water for rivers and lakes, then the habitable land area of Bb might be greater than Earth's. Gravity is the same as Earth's, and in fact the only major difference will be atmospheric composition/density, and the length of the day. And who knows? Maybe we can game those too, by geoengineering the atmosphere, and using a combination of distant orbital sunshades and orbiting mirrors to generate a 24-hour diurnal cycle. Ultimately, Bb could be very earth-like indeed.

The Happy Medium

I expect the reality of Bb's habitability lies somewhere in between the two extremes I've just described. In all likelihood, Bb is not alone; at the very least, there should be asteroids or planetoids of Ceres-size or larger. Bb itself might have a safe spot where industrial operations can be set up, even if it's not a place where you could live. It can export vast quantities of raw materials to colonists elsewhere in the Centauris.

All of which means one thing: Alpha Centauri is now a viable destination. If we can get there, we can live there. And knowing this makes real possibilities that, until yesterday, we could only dream about.

Document Actions

Moving the planet?

Posted by John Ludlow at Oct 18, 2012 03:58 AM
With unlimited energy, could we just move the planet to a higher, cooler orbit?

Energy input

Posted by Karl Schroeder at Oct 19, 2012 08:14 AM
The only tweezers you could pick a planet up with would be gravitational. So you'd need another planet... which presumably you'd have to move somehow as well...

Your other option is to push the thing using radiant energy. The star is already doing that, and nearly melting it. If you provided enough energy to move it to a higher orbit, you'd also be vaporizing it.

So, sure, you can do it, if you're willing to wait around for a billion years or so for it to re-coalesce.
Log in

Forgot your password?
New user?
The Virga Series

(Sun of Suns and Queen of Candesce are combined in Cities of the Air)

Available in Trade paperback May 5, 2012:


Twitter Updates

    follow me on Twitter
    The Engine of Recall - New eBook!

    Read a sample story

    Help support my writing
    Lady of Mazes

    “The most thought-provoking and interesting work of hard SF that I've read in the past year."
    —Charles Stross

    "With paradigm shifts one inside another like a set of Russian dolls, this splendid novel propagates into a demolition derby of Big Ideas. Required post-human reading.”
    —Scott Westerfeld, author of The Risen Empire

    “An astonishing saga. One helluva read!”
    —Charles Harness

    “Karl Schroeder has always had a knack for intelligent and provocative thought experiments disguised as space opera. Now he ups the ante with a fascinating riff on consensual [and conflicting] realities. Lady of Mazes contains more cool ideas than Ventus and Permanence combined.”
    —Peter Watts