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Vorthon from a pale blue dot Since: Feb, 2010
#1: Dec 1st 2010 at 8:52:17 AM

I admit I suffer from ADCD.

Okay, now that I've got that out of the way, I was wondering how the day/night cycle would work for a world like this:

The world is a large torus, and it spins. The sun is smaller than the central hole of the torus and it orbits the small radius of the torus, so that it passes through the hole. What kind of day/night cycle would this produce?

EDIT: I should probably mention this is for a fantasy setting.

edited 1st Dec '10 8:54:17 AM by Vorthon

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
GlassPistol Since: Nov, 2010
CyganAngel Away on the wind~ from Arcadia Since: Oct, 2010
Away on the wind~
#3: Dec 1st 2010 at 9:24:42 AM

A torus is a ring-shaped surface generated by rotating a circle around an axis that does not intersect the circle.

There are too many toasters in my chimney!
Tzetze DUMB from a converted church in Venice, Italy Since: Jan, 2001
DUMB
#4: Dec 1st 2010 at 9:24:48 AM

A donut.

You mean that it loops around on one specific angle of the torus?

[1] This facsimile operated in part by synAC.
Vorthon from a pale blue dot Since: Feb, 2010
#5: Dec 1st 2010 at 9:37:11 AM

[up] uhh... I don't really understand what you mean by that (I need to get more sleep...)

The sun's orbit forms a ring rotated 90 degrees relative to the world (think of links in a chain).

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
Tzetze DUMB from a converted church in Venice, Italy Since: Jan, 2001
DUMB
#6: Dec 1st 2010 at 9:40:24 AM

Right, that's what I meant.

Okay then. Might be better if I new how to have a raytracer so I could model it, but... the area under and near under the sun's orbit would have a standard day-night cycle. The area opposite the outside of the sun's orbit would be in constant night, possibly getting to twilight as the sun rises above the torus. The outside sides would be the same as that. The area inside... bleh... there must be a model somewhere

[1] This facsimile operated in part by synAC.
Yej (4 Score & 7 Years Ago) Relationship Status: They can't hide forever. We've got satellites.
#7: Dec 1st 2010 at 9:42:42 AM

That would be gravitationally impossible, I think. Apart from that, most of the outside edge of the torus would have perpetual night, and the top/bottom of the side opposite the bit the sun's orbiting would have really short days/nights. The rest would have relatively normal day/night.

Vorthon from a pale blue dot Since: Feb, 2010
#8: Dec 1st 2010 at 9:44:00 AM

Well, I was thinking that the torus would rotate, so that no portion of it would be in eternal night/twilight. It does add one more level of complexity to it, though...

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
Yej (4 Score & 7 Years Ago) Relationship Status: They can't hide forever. We've got satellites.
#9: Dec 1st 2010 at 9:53:18 AM

Yeah, if the torus is rotating around an axis that passes through the hole, that'll produce a weird day/night cycle. It would mean that days would be far shorter than nights for any point on the surface.

Tangent128 from Virginia Since: Jan, 2001 Relationship Status: Gonna take a lot to drag me away from you
#10: Dec 1st 2010 at 10:00:23 AM

That'd actually be easy to model with POV-Ray. Poke me later in the afternoon, 'k?

EDIT: The ratio between the planet's rotation speed and the sun's orbit speed would make a big difference. What ratio are you thinking?

edited 1st Dec '10 10:02:09 AM by Tangent128

Do you highlight everything looking for secret messages?
Vorthon from a pale blue dot Since: Feb, 2010
#11: Dec 1st 2010 at 10:14:17 AM

[up]I haven't really thought of that yet... I guess a 1:2 spin-to orbit ration would be the simplest... (We can always try different setups later.)

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
RalphCrown Short Hair from Next Door to Nowhere Since: Oct, 2010
Short Hair
#12: Dec 1st 2010 at 11:42:59 AM

Wait, the torus is rotating around its center, but what is the center of the sun's orbit?

Under World. It rocks!
Vorthon from a pale blue dot Since: Feb, 2010
#13: Dec 1st 2010 at 11:44:24 AM

@Ralph Crown: The smallest radius of the torus.

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
Tzetze DUMB from a converted church in Venice, Italy Since: Jan, 2001
DUMB
#14: Dec 1st 2010 at 11:45:45 AM

Um, a radius isn't an object, it's just a measurement. The sun rotates around the ring, yes?

[1] This facsimile operated in part by synAC.
Vorthon from a pale blue dot Since: Feb, 2010
#15: Dec 1st 2010 at 11:48:37 AM

[up]Like I've pointed out, it's orbit would take through the world's rotational axis, so that the inside portion would be lit all at the same time.

EDIT: and besides, I was using terminology from 3DSmax. I've been using it a lot at work lately.

edited 1st Dec '10 11:49:34 AM by Vorthon

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
RalphCrown Short Hair from Next Door to Nowhere Since: Oct, 2010
Short Hair
#16: Dec 1st 2010 at 2:34:26 PM

Celestial Mechanics 101: objects rotate around the center of gravity of other objects. If the size of the object varies around that center, the pull of gravity likewise varies, which results in an irregular orbit. That's why typical objects are spherical, so that their gravity is regular and orbits are regular.

Upshot is, your sun would orbit around the center of the torus, not the surface, unless you use some serious hand waving.

Of course, in fantasy you don't need to worry about reality. Maybe the sun is a flaming chariot on a Moebius strip that floats around the world. That makes more sense than quantum physics.

Under World. It rocks!
Tangent128 from Virginia Since: Jan, 2001 Relationship Status: Gonna take a lot to drag me away from you
#17: Dec 1st 2010 at 8:05:58 PM

Hmm... let's try this...

edited 1st Dec '10 8:18:57 PM by Tangent128

Do you highlight everything looking for secret messages?
CyganAngel Away on the wind~ from Arcadia Since: Oct, 2010
Away on the wind~
#18: Dec 1st 2010 at 8:14:13 PM

Dammit Tangent, now I'm dizzy @_@

There are too many toasters in my chimney!
Tzetze DUMB from a converted church in Venice, Italy Since: Jan, 2001
Tangent128 from Virginia Since: Jan, 2001 Relationship Status: Gonna take a lot to drag me away from you
#20: Dec 1st 2010 at 8:36:31 PM

You really need to learn yourself some POV-Ray, Tzetze. The scene description language is Turing-complete! tongue

The size of the star may be a bit large in this depiction...

edited 1st Dec '10 8:37:04 PM by Tangent128

Do you highlight everything looking for secret messages?
Yej (4 Score & 7 Years Ago) Relationship Status: They can't hide forever. We've got satellites.
#21: Dec 2nd 2010 at 6:05:34 AM

The scene description language is Turing-complete!
Er... tongue

Vorthon from a pale blue dot Since: Feb, 2010
#22: Dec 3rd 2010 at 8:43:25 AM

I can't see it. What format is it in?

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
Yej (4 Score & 7 Years Ago) Relationship Status: They can't hide forever. We've got satellites.
#23: Dec 3rd 2010 at 8:50:49 AM

It's a You Tube video. Do you have Flash?

Vorthon from a pale blue dot Since: Feb, 2010
#24: Dec 3rd 2010 at 8:56:13 AM

Ahh, that would explain it. I'm posting this from school, and youtube is blocked by the filter.

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke
Vorthon from a pale blue dot Since: Feb, 2010
#25: Feb 16th 2011 at 5:46:28 AM

-pulls out a defriballator.-

Clear!

(Necrobumpity!)

So, yeah, I hate doubleposting... but...

I was wondering how to work moons into this?

As in more than one large moon.

"If there are any gods whose chief concern is man, they can't be very important gods." - Arthur C. Clarke

Total posts: 51
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