Okay, in the general "Stuff about your world" thread there was some serious confusion about what a planet is and how they behave.
I'll try to describe how my world works in this domain, as simply as possible.
"Planet" in my world refers to an enormous sphere of dirt and rock. When you're standing on the surface of the sphere, "down" points toward its center, and the sphere is usually big enough that when you look around you can't visually detect curvature; you appear to be standing on a flat surface. Habitable planets are surrounded by an atmosphere made of breathable air.
"Sun" and "star" in my world refer mostly to members of a single category, with only contextual differences between them: much more enormous spheres made of burning materials that give off incredible amounts of heat and light. When humans were first developing on the surface of Earth, we thought that our sun and all the other stars were different kinds of object because the sun was so much closer to us, so it looked very different.
Planets orbit around suns. The time it takes the planet to make a full circuit is that planet's year. Seasonal variations are produced by things like how the angle between sun and surface changes as the planet moves.
Planets also rotate on an axis (usually). The time it takes the planet to turn fully around is that planet's day. The most visible aspect of the rotation to a person standing on the planet's surface is that the sun appears to move through the sky in regular arcs. Before we figured out astrophysics properly, humans used to theorize that the planet Earth was stationary and the sun moved around it, which is why words like "sunrise" (sun-rise) refer to the movement of the sun instead of the planet. In fact, suns do move, but they drag all their planets along with them; from the planet's perspective, it's the one zipping around twirling on its axis and the sun is just hanging out not doing much of anything.
Planetary movement on the scale of days and years doesn't have any obvious human-scale effects like making the ground shake or similar. It took us a long, long time to figure out that our planet was moving at all.
In between planets and suns is an emptiness called (materially) "vacuum" or (locationally) "space". There is no air there, and only occasionally any solid objects. There is also much less of a notion of "down", because gravity in my world is produced by large solid objects and in space you're far enough away from those that you pretty much seem to be floating directionlessly. Humans in my world learned how to build vehicles that travel between one planet and another, and one of the most important considerations for such a vehicle is that it has to bring its own air along (and, for comfort and convenience, generate its own gravity) because otherwise its passengers would be in big trouble. Also crucial, although less immediately so, is that any other resource you want with you on a trip between planets has to be packed before you leave or delivered along the way. Space is very, very empty. The only thing you can be sure of finding almost everywhere in it is light, and even that there sometimes isn't much of.
All right, your turn. Whose world seems to work like this? Whose world works differently?
Post by Botanical Engineer on May 6, 2015 14:51:07 GMT
I've already written some about universe's planets, so I'll transcribe that and add new information. Planets are cylindrical collections of soil, surrounded by a god of a similar shape but twice the size which produces light. Our planet's radius increases by about the length of an arm (I'd be surprised if we shared length units) every net, at midnight. Planets constantly move in one direction other than up or down. They do not collide. Down is a universal direction and everything is pulled that way in relation to how much stuff is in it. The increase in radius appears spontaneously around the edge of the world. When it does this, the sky lights up with a net like pattern, which are commonly believed to be the spirits of the dead. Planets do not fall down because they are held up by their associated gods. If someone falls off the edge of the world, they will fall down until they hit something. My planet is surrounded by a light producing god, but it constantly slowly changes color and brightness. Night is the very dark time after evening red and before morning red, going more quickly backwards through the day's set of colors, with the darkest moment at midnight when it is a blue that is almost black. If someone could go down slowly enough, they could theoretically get to a nearby planet and probably be fine. Empty space between worlds sounds alarming, but if it's held down toward the planet, I guess you don't need to worry about running out? So planets in your universes have a finite but large amount of water that sits on top of them?
Yes, I forgot to get into that explicitly, but most planets have some amount of water on or in them. Large amounts of surface water is an important consideration in habitability. Where does water come from in your world?
Mine works the same as Leaf’s, as far as I can tell, except that we have not managed to go to other planets yet (and except for the other, clustered, worlds I’m also representing). My explanation here seems different because I was focusing on a different aspect.
Mother Starlight, it looks like some of the posts got in a weird order when you moved them to this thread. Are you able to fix that?
A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A b b b b b c c c c c c c c c c c c d d d d d d d d d d d d e e e e e e e e e e e e e e e e e e e e eeeeeeeeeeeeeeeeeffffffffggggggggghhhhhhhhhhhhhhhhhhhhhhiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiijkkklllllllllllllmmmmmmmmmmmmmnnnnnnnnnnnnnnnnnnnnnnnooooooooooooooooooooooooooooooppppppppprrrrrrrrrrrrrrrrrrrsssssssssssssssssssssstttttttttttttttttttttttttttttttttttttuuuuuuuuuuvvvwwwwwwwyyyyyyy,,,,,.....?!'-
My world's planets seem to be similar to Leaf's, although, as I mentioned in a previous thread, we haven't even considered making any forays into space. All our knowledge of planets and how they function comes from enviromantic observations about our own planet.
Post by Botanical Engineer on May 6, 2015 20:56:41 GMT
It rains every night for most of the night. Most of it soaks into the ground, but people collect some of it to use. Rain is when small drops of water fall out of the sky. What happens when the water all gets used up?
I don't know what happens to your used-up water, but ours just sort of goes around again. It's rarely used up in the sense of being destroyed, it just changes form and gets combined with other things and sometimes needs to be extracted from them. And we also have rain. Water from the surface of a planet evaporates into the air and forms clouds, and some kinds of clouds condense into rain and fall down again.
Post by Botanical Engineer on May 7, 2015 0:14:32 GMT
Some of our water evaporates, because water on top of things eventually dries. But a lot of water is absorbed into plants and the ground, and the amount of rain is always exactly the same, so some of it must just come into existence. I think water isn't literally destroyed, but it becomes a lot less accessible once it has been absorbed into things. I suppose if there's enough of it to begin with, some of it will be ready to use again by the time you need it? I don't think we have clouds.
Post by Botanical Engineer on May 7, 2015 0:44:18 GMT
Oh! That had not occurred to me as a possibility! There are some clinging plants that grow on the sides of the world, so there might be some that grow on the bottom, and get water that way! Which might account for some of the lapses when nothing new is observed for a set. I'll need to write a letter to one of the observation groups at the edge, maybe some of them will know whether that happens! Thank you for the thought!
A lot of the water would still be trapped inside various plants, but some of the water in the soil might go through, so the sky would still need to generate some water, but less than it would if all water in the soil remained absorbed until absorbed from the soil by roots.