Ramifications of a terracentric system?

[Delemental]

Our group is in the midst of a homebrew setting, which has been fairly collaborative in its creation. Recently, our GM stated that the solar system the campaign is in (this is a fantasy high magic game, not sci-fi, just to clarify) is a terracentric one; the main planet is in the center of the solar system, and the sun and other planets rotate around it.

What would be the major differences, if any, that a layperson would notice going from a heliocentric system like Earth to a terracentric one? Obviously, there are issues with real-world physics (like how a planet would have enough gravitational pull to keep other planets in orbit), but I'm not really interested in hearing "this won't work because of <insert long equation here>". I'm more interested in what Joe Everyday might notice.

 

[Yair]

Since for a long time the terecentric model was held as true, it stands to reason there won't be significant differences.

What about the far-away stars? Are they set in the firmament, holes in a great dome? Are there layers of rotating spheres, a-la-aristotle? If so, then what happens when magic is used to travel up far enough as to touch the firmament? Can one pass through it? What is on the other side?

 

[Roman]

Various astronomical phenonema and patterns will be different in a terracentric system, but most ordinary folk would not perceive this at all.

The one significant change would be that there would be no seasons - the climate would remain the same year round. This could be 'corrected' by either changing the tilt of the Earth throughout the year in a cyclical pattern, or having the Sun orbit in a highly eliptical orbit. The latter solution would, however, mean that the seasons would be the same in both the southern and northern hemisphere simulatneously.

Apart from the problem with seasons, though, I do not think there is anything else Joe Everyday would notice except perhaps that the tides would work somewhat differently.

 

[Ibram]

Actualy according to Einstein there would be no change (this assumes that the moos of other planets still orbit their parent planet).Some astronmical phenomona would not exist (like that funny thing that Mars does from time to time).

 

[Roman]

Actualy according to Einstein there would be no change (this assumes that the moos of other planets still orbit their parent planet).

There would be a huge change - there would be no seasons. However, it could be corrected for by making the Earth change tilt cyclically where one tilt cycle would equal one year.

 

[RangerWickett]

Of course there'd be seasons! I mean, if I were the god of the dead, and my girlfriend tried to skip town, I'd be pissed too.

 

[arche]

There really wouldn't be any major changes to the individual people. In fact it makes more sense to think that the sun revolves around the earth. It does in fact rise on one side of the sky and then set in the other side of the sky. Common sense would show that it was the sun moving and not the earth.

 

[GrumpyOldMan]

There would be a huge change - there would be no seasons. However, it could be corrected for by making the Earth change tilt cyclically where one tilt cycle would equal one year.

The world Glorantha is flat. Every morning the gates of the dawn crash open and mighty Yelm god of the Sun rides out on his feiry chariot. He rides across the sky to the gates of the dusk, spends the night travelling across the underworld and starts his sky journey again the next morning. For some of the year his path across the sky takes him over the northern part of Glorantha, at other times it takes him to the south. This combined with the battles between gods of Storm and Ice creates the seasons. This 'cyclic tilt of a globe' you postulate is a heresy against the gods.

Why should the world be a sphere? Why don't people on the bottom simply fall off? There is no reason! So the world must be flat!

Is there a horizon on a flat earth? Well: light, by which we see, is a property of the Sun and Sky, so has a tendency to curve up, away from the flat surface and towards the sky where it belongs. This means that as you travel out to sea you lose sight of land.

There are reasonable and logical explainations to these things, ask your priest.

GOM

 

[Umbran]

There would be a huge change - there would be no seasons.

That depends.

If you produce your day/night cycle by having the sun orbit the planet once each day, yeah, your seasons have a problem.

If, however, the day/night cycle is still produced by spinning the main planet, and the sun orbits the planet once each year, you can still produce normal seasons with a standard steady axial tilt on the planet.

 

[DMScott]

What would be the major differences, if any, that a layperson would notice going from a heliocentric system like Earth to a terracentric one?

Almost none, though it depends somewhat on how much work your gods/magical beings/whatever are doing to keep the universe looking that way. You can treat our universe as terracentric (or "geocentric" as it's traditionally called) and build a workable mathematic model of everything we see, you just end up with some weirdly complicated orbits and no good scientific reason why they should be so strange. Seasons, eclipses, and other phenomena can all work with a geocentric universe if you're prepared to specify that the sun and other bodies have irregular orbits, and the only people who'll be puzzled would be your world's equivalent of Galileo, Kepler, Copernicus, Tycho Brahe, etc.

So if your world hasn't advanced to 15th-16th century technology and science, no problem. If it has, you might end up with a version of the Galileo-church conflict, except this time the church is in the right - that might be a neat plotline.