52
physics
× 4 |
15
seasons
|
8
climate
|
0
apocalypse
× 2 |
48
science-based
× 11 |
15
flora
|
7
society
× 4 |
0
earth-like
|
45
ragnarok
× 2 |
13
materials
|
7
games
|
0
avian
|
45
religion
|
13
engineering
|
7
ethics
|
0
intelligence
|
45
solar-system
|
12
weapons
|
6
black-holes
× 2 |
0
politics
|
36
reality-check
× 7 |
9
names
|
6
gravity
|
0
post-apocalypse
|
34
space
× 6 |
9
language
|
4
technology
× 2 |
0
colonies
|
26
planets
× 3 |
8
creature-design
× 2 |
4
civilization
|
0
psychology
|
23
biology
× 6 |
8
evolution
× 2 |
4
technological-development
|
0
reproduction
|
15
astronomy
× 4 |
8
underwater
|
1
magic
|
|
15
orbital-mechanics
|
8
terraforming
|
1
science-fiction
|