Building the worlds of the ENIGMATIC universe, part 2

As promised, here is the continuation of the previous post, in which we discussed the radii of super Earths. After some research, I did find a few tidbits that I think will get us in the right direction. Summing up various information that I stumbled on, the most definitive thing I found sums things up thusly - "The largest 'terrestrial' planet is generally considered the one before you get an atmosphere gets too thick, which happens at about 5-10 Earth masses (something like 2x Earth radii)."

It's not much, but it's a start. We know the bottom end is going to be a size 8 planet (1 Earth radii, 1 Earth mass, 1g gravity) from the chart in the last post. The top end was also assumed to be size G, with twice the radius of Earth. I'm assuming that the largest super Earth uses the upper bound for statement above, about 10 Earth masses. For everything in between, we'll just assume an even distribution of Earth masses. That will just leave us with gravity, and that can be calculated fairly easily. A little bit of rounding, and viola', a size table for super Earths. It's probably not scientifically accurate, but I think it will be playable.

Radius                Earth radii         Earth masses                    Gravity

8   12,800 km	1 Earth	1 Earth mass		1.0 g
9   14,400 km	1.125 Earth	1.25 Earth masses		1.3 g
A   16,000 km	1.25 Earth	2.5 Earth masses		1.6 g
B   17,600 km	1.375 Earth	3.75 Earth masses		1.9 g
C   19,200 km	1.5 Earth	5 Earth masses		2.2 g
D   20,800 km	1.625 Earth	6.25 Earth masses		2.3 g
E   22,400 km	1.75 Earth	7.5 Earth masses		2.4 g
F   24,000 km	1.875 Earth	8.75 Earth masses		2.5 g
G  25,600 km	2 Earths	10 Earth masses		2.6 g
H   Neptune size	2 to 6 Earths
J   Jupiter size	6 Earths+

For use in CE, I wouldn't use size B or greater as the main world in the system, just secondary worlds in the system itself.

Next up, a look at how I'm generating the future history of ENIGMATIC, and possibly a sneak peak at a product I'm working on to help you do the same for your towns, stations, planets, systems, and empires.

See you soon!

Donavan L.

dslironworks@gmail.com

Building the worlds of the ENIGMATIC universe, part 1.

The first step of building any setting is figuring out where the action is going to take place. For ENIGMATIC, I've already decided on the area of space covering a sector sized area around Earth. So, I know where the stars are, and since we're working with actual data, those details can be looked up rather than generated for the most part.

One of the things that I wanted to incorporate from the beginning was some detail about known exoplanets, which I'm discovering is a daunting task - more are discovered every day, and more effort is being made to detect them. Currently, we've found on the order of 2,100 planets in 1342 system, including 509 multiple planet systems. That's a lot of data, and it's growing all the time. Happily, I can cull it down to data for 110 stars close enough to show on the map.

9  14,400 km - 1.125 Earth
A 16,000 km  - 1.25 Earth
B 17,600 km - 1.375 Earth
C 19,200 km - 1.5 Earth
D 20,800 km - 1.625 Earth
E 22,400 km - 1.75 Earth
F 24,000 km - 1.875 Earth
G 25,600 km - 2x Earth
H Neptune size - 2x to 6x Earth
J Jupiter size - >6x Earth

Digging into the information we have, the most commonly known data is the mass of the planet and quite often the orbit it occupies. That's enough to get started, if a couple of assumptions are made. Since Cepheus Engine doesn't track density, we can assume that radius and mass scale linearly for my purposes. That assumption is probably wrong, but we'll start with that. Looking at a lot of the exoplanet data, many are up to 2x the size of the Earth. The problem is, the planet size table in CE only goes up to size A, or 16,000 km. Since the UWP can handle expansion, we end up with something like thisH and J will essentially cover small and large gas giants (something lacking from the UWP anyway). Obviously, H and J won't be used for main worlds, but since I plan on having UWPs for all of the planets in a system, it's worth having a tag for it.

I was toying with a much shorter table, essentially 3 entries - one for generic Super-Earths, one for Neptune sized, and one for Jupiter sized. A quick Google search suggested humans could live on a world with as much as 3-g gravity, but it would be definitely unpleasant, and probably wouldn't happen. But, having access to a more definitive set of ratings gives referees the option to send their unsuspecting players down onto a 3-g world to retrieve the mcguffin, and that fits in with the grittier, more dangerous feel I'm going for with ENIGMATIC.

So, I've got the radius figured out, and Richard Hazelwood on the CE Facebook page mentioned that density does NOT scale linearly with size, so mass and gravity won't either. Since the CE size table includes gravity, I'll have to do some research into how density does scale, and figure out the respective gravity for each entry. Look for part 2 of this post in the near future. See you soon!


Donavan L
dslironworks@gmail.com

It's a new day in America.  2016, with all of it's twists and turns, is finally behind us. It was a tough year for DSL Ironworks on a number of fronts. By far, the thing that caused the most upset was the release of Traveller 2.0 (which dragged on about 5 months too long) and the formation of the Travellers Aid Society on Drivethrurpg.com.  As you've probably heard, Mongoose did away with the Traveller Logo License and the Foreven Free License, which was what all of the products produced by the Ironworks were under. All new Traveller material, whether for the OTU or standalone settings, is to be released ONLY under the Travellers Aid Society, with a increase in the royalties paid to Mongoose and Drivethrurpg. This, along with the changes to the licensing regarding IP, made me take a hard look at what I was doing and how to proceed.

In July, Jason "Flynn" Kemp released the Cepheus Engine, a 2d6 OGL retro-clone of classic Traveller. After having a look, I liked what I saw, and decided it was time for a change. With a new rule set, and the OTU looking less palatable, a new setting seemed to be in order. By building the setting from the ground up, and basing it in a true OGL ruleset, I decided we had found a way forward. But, what kind of setting?

My true love in sci-fi has always been near future, gritty, and between 3.5 and 4.2 on the Mohs Scale of Sci-fi hardness. That is, relatively hard science, with a few caveats here and there for flavor. Movies and shows that I feel fit into this include Alien and Aliens, Blade Runner, Soldier, The Expanse series, Space: Above and Beyond, Outland, Pitch Black, and Space: 1999. So that is where I decided to head. The basics are covered in the proposal document, and cover most of what I'm aiming for.

Since late September/early October, I've been putting the pieces in place to get the setting up and running under the title ENIGMATIC. Using the Near Space map from Stellagama Publishing as a base (because it's OGL, incorporates a sector of space surrounding the Earth, and why reinvent the wheel), I put together a database for the 110 or so worlds closest to Earth. In order to help put together a timeline with interesting events, I assembled well over a hundred different events, ranging from natural disasters and civil wars to industrial disasters and missing space ships. I've also put together a way to keep track of groups and foundations, etc There's a ton of information already generated for the setting, and I'm starting to pull it all together into a coherent setting.

This blog is going to follow the development of the ENIGMATIC setting as it grows. I'm aiming for a weekly post on Saturday nights (since I now have Friday and Saturday off from the day job), with other posts during the week as needed. I've also updated my Patreon page, so if you'd like to support me and get some additional goodies, that is an option for you as well. 2017 is going to be a great year, and I hope you'll join me for the ride!

Donavan L., dslironworks at gmail dot com