Thursday, January 26, 2017

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.

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