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

Light pollution: space elevator show-stopper?

Filed Under:

And what would the 'light footprint' of solar power satellites be?

With the addition of its final set of solar panels, the international space station is slated to become the second brightest object in the night sky--brighter than Venus.  Now, admittedly the ISS is the size of a football field, but it's also three hundred kilometers away from the Earth directly above the plane of its orbit--but much further away for most of the people who see it.  Thousands of kilometers, for most of us.

Consider this:  on any given night, you can look up (if you're not in a city that already drowns the stars) and see satellites.  They're hundreds of kilometers away, and the biggest are no larger than a compact car--yet you can see them.  Most are the size of a barrel, but perfectly visible.

Consider Bradley Edwards' ribbon design for the space elevator cable.  This would be a meter or two wide and curved, so that it is effectively visible from all angles.  So it's about the width of a barrel, but infinitely longer.  Its reflective surface over one kilometer's distance would be at least as great as the ISS; but please multiply that light output by 35,000 because that's how many kilometers long it would have to be.  A Hoytether (open meshwork) design would presumably reflect less, but how much less?

You could paint the ribbon black.  Then again, how much would a coating weigh that had to cover 1 meter x 35 million meters of area?  The black coating would heat the cable because the sun is so intense in orbit, so you wouldn't want it to be totally absorptive.  But here's the thing:

The moon is black.

Actually, overall the moon's surface is about the shade of an asphalt highway. It absorbs almost all the light that hits it.  The moon appears pearly white to us only because of the tiny fraction of light that's reflected off the lunar blacktop.  So even a mostly-black ribbon would look brilliantly white to us on the ground.

As if all this were not enough, the only practical means of powering the climber cars (which would be visible too) appears to be multi-megawatt lasers, aimed at solar cell arrays on the climbers.  As Wikipedia puts it:

The proposed method is laser power beaming, using megawatt powered free electron or solid state lasers in combination with adaptive mirrors approximately 10 m wide and a photovoltaic array on the climber tuned to the laser frequency for efficiency.

So, the climbers are in the cross-hairs of, essentially, a set of a huge spotlights.  Maybe you could use infrared or ultraviolet lasers, but if not, then even for the most efficient solar cells (40% or thereabouts) 60% of the laser light will be absorbed or reflected.  Add to that light from the sun reflecting off the (presumably large) collectors, and you get something fiercely bright climbing the already bright cable.

This issue doesn't just affect the space elevator, by the way.  It's also relevant to any substantial effort to place solar power satellites at geosynchronous orbit.  Their immense surface area would pretty much guarantee that they'd shed a vast amount of light on the Earth.

But why should we care?  Here again we can refer to Wikipedia, in its entry on light pollution:

Life exists with natural patterns of light and dark, so disruption of those patterns influences many aspects of animal behavior.  Light pollution can confuse animal navigation, alter competitive interactions, change predator-prey relations, and influence animal physiology.

...Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia, from eating surface algae, helping cause algal blooms that can kill off the lakes' plants and lower water quality.

Lots of other life forms are affect--everything from birds to frogs.  It doesn't take very much light to have a big effect. So, in the absence of any direct physical effects, the space elevator would still have a large, if not catastrophic, ecological impact.

I wish this weren't true.  I'm a big fan of the elevator, and an even bigger fan of solar power satellites.  But the devil, as they say, is in the details.  If these structures cause the amount of light pollution I'm suggesting, then they are very far from being green options for energy and transport--regardless of how much carbon they may offset.


Document Actions

Appendix: alternative ribbon materials

Posted by Karl Schroeder at Mar 12, 2009 08:13 AM
There's two potential ways of rendering the ribbon or hoytether invisible: one is to fan out the nanotubes rather than braiding them into solid cables. Single-walled carbon nanotubes are smaller than the wavelengths of visible light, so they would literally be invisible to us; though, not necessarily to every kind of life on Earth.

The other option might be to use a graphene ribbon instead of CNT. Graphene is normally transparent, but only because it's made in very thin quantities. It does absorb 2.3% of white light that hits it. Still, it might be transparent enough. Whether this would work mechanically I don't know; in any case, while transparent overall, graphene will still reflect and refract some of the light that hits it. So the lunar blacktop problem still remains, as does the potential problem of transient flashing from a turning or swaying ribbon.

Light pollution

Posted by Fred Zimmerman at Mar 16, 2009 02:51 PM
Good point, but I'm having a hard time believing that the amount of light pollution from geoengineering would be significant relative to the amount of anthropogenic light pollution emitted from the ground. Can you quantify?

Up or downward pointing lights

Posted by Karl Schroeder at Mar 17, 2009 05:54 AM
The significant difference is that the elevator illuminates an entire hemisphere of the planet. There is therefore no escaping its effect, whether you're in the Amazon jungle or floating on a raft in the Pacific. Question: has anyone studied the effects of light pollution on oceanic plankton?

The total area of the elevator could be equal to a seven-by-seven kilometer mirror suspended above the planet. If the ISS is already the second brightest object in the sky, how much brighter would that be?

Neither the space elevator nor power satellites are geoengineering projects, by the way. The inadvertent light pollution from them IS a geoengineering side-effect; that's my point.
Log in

Forgot your password?
New user?
About Me

I'm a member of the Association of Professional Futurists with my own consultancy, and am also currently Chair of the Canadian node of the Millennium Project, a private/public foresight consultancy active in 50 nations. As well, I am an award-winning author with ten published novels translated into as many languages. I write, give talks, and conduct workshops on numerous topics related to the future, including:

  • Future of government
  • Bitcoin and digital currencies
  • The workplace in 2030
  • The Internet of Things
  • Augmented cognition

For a complete bio, go here. To contact me, email karl at kschroeder dot com

Example: The Future of Governance

I use Science Fiction to communicate the results of actual futures studies. Some of my recent research relates to how we'll govern ourselves in the future. I've worked with a few clients on this and published some results.

Here are two examples--and you can read the first for free:

The Canadian army commissioned me to write Crisis in Urlia, a fictionalized study of the future of military command-and-control. You can download a PDF of the book here:

Crisis in Urlia

For the "optimistic Science Fiction" anthology Hieroglyph, I wrote "Degrees of Freedom," set in Haida Gwaii. "Degrees of Freedom" is about an attempt to develop new governing systems by Canadian First Nations people.

I'm continuing to research this exciting area and would be happy to share my findings.


Twitter Updates

    follow me on Twitter
    Mailing List

    Stay informed about new book and story releases, public appearances, readings etc.

    * indicates required
    Coming on June 18, 2019

    "Science fiction at its best."

    --Kim Stanley Robinson

    A Young Adult Scifi Saga

    "Lean and hugely engaging ... and highly recommended."

    --Open Letters Monthly, an Arts and Literature Review

    Sheer Fun: The Virga Series

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

     β€œAn adventure-filled tale of sword fights and naval battles... the real fun of this coming-of-age tale includes a pirate treasure hunt and grand scale naval invasions set in the cold, far reaches of space. ”
    β€”Kirkus Reviews (listed in top 10 SF novels for 2006)

    "With Queen of Candesce, [Schroeder] has achieved a clockwork balance of deftly paced adventure and humour, set against an intriguing and unique vision of humanity's far future.
    --The Globe and Mail

    "[Pirate Sun] is fun in the same league as the best SF ever has had to offer, fully as exciting and full of cool science as work from the golden age of SF, but with characterization and plot layering equal to the scrutiny of critical appraisers."

    "...A rollicking good read... fun, bookish, and full of insane air battles"

    "A grand flying-pirate-ship-chases-and-escapes-and-meetings-with-monsters adventure, and it ends not with a debate or a seminar but with a gigantic zero-gee battle around Candesce, a climactic unmasking and showdown, just desserts, and other satisfying stuff."