Frequently Asked Forum Questions Search the HBO News ArchivesAny All Exact Search the Halo Updates DBsHalo Halo2 Search Older Posts on This Forum:Posts on Current Forum | Archived Posts

 Re: Speculation on water loss Posted By: Grady Date: 9/26/03 12:16 a.m. In Response To: Re: Speculation on water loss (Plastic Chicken) : How Halo gets its gravity is very simple (and fundamental): It's a ring, and : it rotates. The centrifugal force creates gravity. That's why it's a ring : in the first place, and that's why the ecological part of the ring is on : the inside, not the outside, of the ring. The outside of the ring has : negative gravity. : If humankind ever makes a self-sustaining space station with an ecosystem, do : you know what shape it'll be in? Yep, a ring. Rotating it would then : produce gravity and distribute heat (whereas heat on earth is very : ambient, heat in space (near a star like the sun) is much more direction, : rotating a ship in space is a lot like rotating a marshmellow over a : fire). : What would that have to do with hydrogen escaping? I'd consider it unlikely, : because where on a planet if a hydrogen molecule escapes it might rocket : away into orbit (speculation), on halo it'd just fly across to the other : side...or it could miss (which might be more likely)...anyway, I don't : think the process would happen fast enough to cause the water to drop : significantly over any short period of time. Or long period of time, for : that matter. : Ok, that's the rant for now. I'm actually not convinced Halo gets its gravity by rotation. My reasoning is as follows: In the opening cinematic of Pillar of Autumn, we see that the ring is oblique to the sun, so that half of it is lighted and half is dark. With that geometry, a Halo "day" will be exactly as long as the rotation period. Now, to get Earth-level gravity (9.81 m/s^2) on a "planet-sized" ring (assuming 6378 km radius, same as Earth's mean equatorial radius), the ring needs to rotate once every 84 minutes. Even to get half a gee, it would need to rotate every 119 minutes, and this simply does not jibe with what we've seen in the game. The sun would be over the horizon only 60 minutes at most, sunrise to sunset, and we'd certainly be able to notice that in long outdoor levels like Halo or Assault on the Control Room. In fact, we see fixed lighting which implies (assuming Bungie wasn't being lazy, and they do indeed seem to pay attention to details) that Halo has a fairly long day, on the scale of Earth's. (In fact, to get one gee we'd need a ring 3.7 million km in diameter, probably bigger than the gas giant Threshold's moon system, let alone the planet itself.) As for what that has to do with hydrogen escaping, it's just a matter of figuring out the criterion for whether or not a molecule will escape. For a spinning ring, it should be straightforward to figure out that criterion; for a generated-gravity system it's hopeless, because we don't know any details of the generated field. (Actually, on further calculation, if Halo *is* getting its gravity entirely from spin, its peripheral velocity is 8 km/s which should be about how fast an H2 molecule or H atom (since that also gets produced in the upper atmosphere) would need to be going to escape. That's fairly fast -- Earth escape velocity is 11 km/s -- but does make Halo intrinsically leakier than Earth, though not as bad as Mars. I imagine a lot gets lost over the edges of the ring, though, depending on how high they are. So many things we don't know about Halo's design...) --Grady

 Replies:

 Speculation on water loss Grady 9/25/03 1:29 a.m. Re: Speculation on water loss Infininja 9/25/03 3:58 p.m. Re: Speculation on water loss Grady 9/25/03 4:59 p.m. Re: Speculation on water loss Infininja 9/25/03 5:55 p.m. Re: Speculation on water loss AlianAnt 9/25/03 6:05 p.m. Re: Speculation on water loss Infininja 9/25/03 6:12 p.m. Re: Speculation on water loss Grady 9/25/03 10:14 p.m. Re: Speculation on water loss Viscily II 9/29/03 6:54 p.m. Re: Speculation on water loss Micahst 9/25/03 8:56 p.m. Re: Speculation on water loss Micahst 9/25/03 9:02 p.m. Re: Speculation on water loss Plastic Chicken 9/25/03 10:43 p.m. Re: Speculation on water loss Plastic Chicken 9/25/03 10:46 p.m. Re: Speculation on water loss Infininja 9/25/03 10:54 p.m. Re: Speculation on water loss Plastic Chicken 9/27/03 10:01 p.m. Re: Speculation on water loss Grady 9/26/03 12:16 a.m. Re: Speculation on water loss Grady 9/26/03 2:09 a.m. Re: Speculation on water loss Infininja 9/26/03 7:19 a.m. Re: Speculation on water loss Grady 9/26/03 12:12 p.m. Re: Speculation on water loss Infininja 9/26/03 1:21 p.m. Re: Speculation on water loss Plastic Chicken 9/28/03 1:25 a.m. I meant m/s/s *NM* *NM* Plastic Chicken 9/28/03 2:06 a.m. Re: Speculation on water loss Dwain 9/29/03 7:37 a.m. Re: Flood alter the atmosphere? Wado SG 9/29/03 1:21 p.m.