Some Handy Tools for Science-fiction World Building

Originally I had planned to use a real-world star for the home star system of the Star Commonwealth of Arcadia. That star was going to be Beta Canum Venaticorum, a.k.a. Chara. It seemed like a good candidate because it's a Sol analog, and isn't that far away from Earth, a mere 27 some-odd light years away. (Precise measurements of the star's distance vary. See: http://en.wikipedia.org/wiki/Beta_Canum_Venaticorum for a starter discussion of the star, references, and links. To date, no planets have been spotted at Beta Canum Venaticorum, but that doesn't mean they aren't there.) The star could, in theory, have an Earth-like planet. My idea at first was that a nearby star system would be settled by refugees from Earth, and a Sol analog was perfect, but then I decided Chara was too close to Earth. I liked the idea of a star system far away. It gave me more elbow room to flex the muscles of my star nations, which I like. Greater distance also made it easier to work the theme of Earth-is-lost into the long range story line. But I kept Beta Canum Venaticorum as my model for the home star of the Commonwealth.

Several years ago I found a star system generating program online, StarGen. It came in very handy for generating random star systems given a few parameters to start with, like the mass of the parent star. I used StarGen online to generate a batch of hypothetical star systems for Beta Canum Venaticorum. One of those models became the star system I now use as the home of the Star Commonwealth. That model included the double planet system known in my stories as Terra Arcadia and its large moon Elysion. It also included a third Earth type planet in the star's hab zone! It was too good to be true. I had a model star system with three Earth-like worlds, two of which were super Earths. The model also included a number of other interesting worlds, Jovian, Martian, Venusian, sub-Jovian, thirteen planets in all. I grabbed it and ran. The Shara star system was now more than just a few ideas scribbled on paper.

BTW, StarGen is not accessible at the time of this posting. You can find the site here: http://fast-times.eldacur.com/StarGen/RunStarGen.html, but when I last checked (19 Dec 2013) it was not possible to generate star systems online, and the links to the rest of the website appear not to be working. Hopefully it will be back up and running in the future.

Some time after creating my model star system with StarGen I found AstroSynthesis. AstroSynthesis is now in its third incarnation. It is more than just a star system generator. It will generate an entire volume of space light-years across, with hundreds and even thousands of randomly generated star systems! Fantastic! See the link below. The software is not free, but there is a free trial version, and it is well worth the cost for anyone wanting to create worlds for a science fiction universe.

I used AstroSynthesis to fine tune my model of the Shara star system, adding a small moon to Terra Arcadia.

Other online tools came in handy for fine tuning the individual planets of the star system. How does one calculate the Hill Sphere of a planetary body? The Roche Limit? The angular size of planetary bodies or the parent star seen from a distance? The orbital data of a planet? What about the relationship between planetary mass, density, and gravitational pull? And so on. I'm not all that mathematically skilled. Despite having two grad degrees, I barely survived Algebra 2 in high school way back in the Dark Ages. I get the basic mathematical concepts, of course, but a little thing called dyslexia, perhaps with its attendant co-morbidity dyscalculia, kind of gets in the way of handling some of these mathematical problems. Fortunately there are numerous calculators online that can are designed to handle these problems. See the links below.

Unfortunately a few of the online tools I have used to create my worlds are no longer accessible, and I have not included them in the list below. (One example is something that used to be found as astro_calculator.htm, a Java script calculator that I can find nowhere on the web now. It was a very useful program.) The one exception to this is StarGen, which I list in hopes it will return, new and improved.

Celestia is also another great program, useful for checking out real-world stars and known exoplanets, but at the moment I can't access the website. Hopefully this is a temporary situation.

Also, check out the world-building links at Orion's Arm, Hidden Way, and Project Rho in the list below. There will be other world-building sites useful for creating star systems and planets, but these are the bulk of what I have used. One word of caution: not all planet-building calculators will agree, given the same input.

And finally, Online Conversion has a ton of useful calculators. I find the length-distance conversion calculator to be especially helpful in converting from US miles/feet, etc., to metric.

 

Links

AstroSynthesis 3:http://www.nbos.com/products/astro/astro-generator.htm

Star Gen (may not be supported!):
http://fast-times.eldacur.com/StarGen/RunStarGen.html

Angular Size Calculator:
http://www.1728.org/indexast.htm

Astronomy and astrophysics calculators:
http://www.calctool.org/CALC/phys/astronomy
 ...and a whole host of other neat calculators at the site home page:
http://www.calctool.org/CALC

Boiling point calculator:
http://www.calctool.org/CALC/chem/substance/boiling

Celestia (link not working on 19 Dec 2013 for some reason, hopefully back soon):
http://www.shatters.net/celestia/

Circle and Sphere calculator:
http://www.csgnetwork.com/circle_sphere_area_calculator.html
 
Gravity Calculator:
http://www.ericjamesstone.com/blog/home/gravity-calculator-for-astronomical-bodies-based-on-radius-and-density/

Habitable zone calculator:
http://depts.washington.edu/naivpl/sites/default/files/HZ_Calc.html 

Hidden Way:http://hiddenway.tripod.com/world/ 

Hill Sphere, Interior and Exterior Reach, Velocity calculators (and more):
http://orbitsimulator.com/formulas/

Online Conversion:
http://www.onlineconversion.com/

Orion's Arm:http://www.orionsarm.com/xcms.php?r=oa-page&page=gen_worldbuilding_links 

Plan a Planet Orbiting a Main Sequence Star:
http://www.oocities.org/albmont/mseqstar.htm

Planet Designer:
http://www.transhuman.talktalk.net/iw/Geosync.htm

Project Rho:
http://www.projectrho.com/public_html/starmaps/software.php

Temperature conversion calculator:
http://www.lenntech.com/calculators/temperature/temperature.htm


　

pax, J Allen W