# Lucius'



## Marky Lazer (Nov 23, 2005)

*I'm not sure if this is the proper place to post, if not, please move to the appropriate section*

Together with a mate of mine, we did some Maths to find things out:

First, don’t ask me why, but the city is moving instead of standing still like a normal city.

Lucius (planet) is 24,902 miles all the way around, at the equator (same as Earth). That means that at 1 mile an hour, the city would take 24,902 hours to go around the world (literally one mile for every hour). 
A day (or one full rotation of a planet) on Earth is 24 hours. On Lucius, it needs to be 24,902 hours, so that they can constantly outrun the sunset. So Lucius' "days" are over 1,000 times longer than ours. 
In order to make the 'days' on Lucius so long, we need to slow down the planet's rotation. The Earth rotates 365.25 times (a year) in one whole orbit around the sun. In order for the sunset to move slowly enough for Arret (city) to outrun it, you would need Lucius to rotate fully once every 2.84 orbits around the sun. So Lucius does almost three laps before it rolls all the way around. 

Does this make _any_ sense?


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## chrispenycate (Nov 23, 2005)

Marky Lazer said:
			
		

> *I'm not sure if this is the proper place to post, if not, please move to the appropriate section*
> 
> Together with a mate of mine, we did some Maths to find things out:
> 
> ...


No need- if you tide lock the planet- (1 year=1 day) so that one side permanently faces the sun, (like the moon with the earth) then apply a very slow spin (an asteroid impact, or even a close flybye) you can get your spin in either direction, even in any axis. The weather on such a planet is going to be something to write home about- the fact that air is a solid on one hemisphere, but which one keeps changing gives you a permanent hurricane at your dawn edge, a snowstorm starting with water, then carbon dioxide and the other atmospheric components at your dusk edge, with the newly gaseous air rushing from sunrise to twilight- any organisms evolved there would doubtless be very streamlined and, like the city, migrate permanently against the wind (or freeze solid. And I haven't even started on plant analogs yet)
No oceans, the surface scraped flat by a near permanent sandstorm- I don't think I'm ready to move there just yet


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## Marky Lazer (Nov 23, 2005)

I don't think I want the planet to be tidally locked. It's of big importance that the planet IS rotating.


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## chrispenycate (Nov 23, 2005)

That's why I hit it with an asteroid- start with a nice, stable situation and add a few terrajoules of energy.

Actually, Venus isn't far from your specified conditions, and  doesn't suffer the weather I was anticipating, possibly due to the etreme cloud cover (quite probably due to me having slipped a decimal point when estimating heat lost by radiation into space) If you put it round a slightly cooler star, siphoned of 95% of the athmosphere and left it a couple of million years, it might work all right without having to build one from scratch
http://www.jimloy.com/astro/venus.htm


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## Marky Lazer (Nov 23, 2005)

My head hurts after reading all that. I thought we made a plausible story without the use of asteroids and all. Back to the drawing table or can I get away with my story?


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## chrispenycate (Nov 23, 2005)

Marky Lazer said:
			
		

> My head hurts after reading all that. I thought we made a plausible story without the use of asteroids and all. Back to the drawing table or can I get away with my story?


Go with yours- the asteroid strike would have been tens of millions of years before, anyway. I was just bothered about the weather- my calculations gave me about minus 210° C before dawn (noticably chilly, and a good reason for the city not to break down) for temperatures over 50° C noon, while Venus gives me negligible difference between day and night.


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## Marky Lazer (Nov 23, 2005)

Thanks for your help so far, but I'm going to pester you a bit more...

I'm not sure about the weather part. If the rotation of this planet is as slow as I suggest it is, what does that say about the weather?


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## AmonRa (Nov 23, 2005)

rain will be very heavy ?


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## chrispenycate (Nov 23, 2005)

Marky Lazer said:
			
		

> Thanks for your help so far, but I'm going to pester you a bit more...
> 
> I'm not sure about the weather part. If the rotation of this planet is as slow as I suggest it is, what does that say about the weather?


Think about the length of time the sun keeps shining on one area- how hot does it get? And how cold where the sun isn't shining? The atmosphere is going to try and equalise this, both by retaining some heat, and by hot air expanding into colder regions. An extremely rough calculation (based on energy- I'm no meterologist) gave me wind speeds roughly five times the recent hurricanes, as standard. "go fly a kite" becomes a death wish. Continuous thick cloud cover would reduce the temperature differences, and thus the energy available. Entire oceans evaporating at noon, and refilling with torrential rainfall at dusk, to freeze in the dead of night would also help to stabilise temperature, but cause some other energy cycles.
I'm sorry, I can't help imagining the results graphically- no permanent mountain chains, because temperature cycling like that would erode them down in a couple of centuries, near permanent small earth tremors but practically never a major quake- perhaps I'd better stop and let you mull over the wisdom of letting me start.


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## Marky Lazer (Nov 23, 2005)

This is most useful! Thanks again!

I might start calling you Oracle from now on.


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## dreamwalker (Dec 20, 2005)

Yeah, chris is very right.
Your weather on your planet is gunna be crazy.

You could probably work out the math for this. but your planet would take roughly 24,900 hours plus the 365.25 days - to be fully immuniated on all sides by the sun at an 1au orbit when rotating at 1 mph.
this is because planetary axis revolutions are absolute messurements and your point around the orbit will change which direction the star would be (in relation to the rest of the universe).

:S
I hope that makes sense.


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## HieroGlyph (Dec 23, 2005)

Marky, is your Arret, the city, surface bound?
I was thinking that it would be far simpler to have a floating city instead of trying to control so many other (huger) variables.
Chris, any idea of the feasability studies upon a floating city???
Yours, stirringly,
HG


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## Rosemary (Dec 23, 2005)

Actually Chris did a piece called 'Aquatic Musings'in the Science Nature thread that might be of interest for a floating city.


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## HieroGlyph (Dec 23, 2005)

AH, thanks for that. I suppose a city on water might manage to solve Marky's queries, but I was thinking of a city up in the air .


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## Rosemary (Dec 23, 2005)

Sorry, didn't read far enough back in the thread!! 

*'Entire oceans evaporating at noon, and refilling with torrential rainfall at dusk'*

I spotted that sentence which was probably my only excuse...


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## chrispenycate (Jan 10, 2006)

HieroGlyph said:
			
		

> AH, thanks for that. I suppose a city on water might manage to solve Marky's queries, but I was thinking of a city up in the air .


Oops- missed this one. Certainly either air cushion or lighter than air (really *big* zeplins) would solve the problems of surface erosion (though the latter would give Marky problems getting his protagonists to ground level) Still, with wind speeds peaking at somewhere between "ooh, nasty" and "ruddy unbelievable" we really need contact with the ground to progress. 
In fact, I don't think rollatron tyres would be adequate; thousands of caterpillar tracks mounted onto a semi rigid structure, with expanding shock absorbers to take up the irregularities of the terrain, and each one capable of being lifted into the interior for servicing (and a continuous maintenance cycle as well as repairs to any damaged units- they must have a source of metals and an extensive industrial capability aboard)
More interesting to me is where the city dwellers came from- while species migrating in one of the climatic zones are quite probable, nothing evolved on that planet would ever build a city- nomadic herders possibly, but never builders. So they must have come from elsewhere- perhaps even Earth? A scientific expedition, or a colony ship that has no alternative but to settle on this very unpromising world? My pictures include harvesting machines (the city being in the afternoon/autumn zone) either automated or run by small crews. and a wide swathe of earthly vegetation and ahead of the city, migrating closer to noon, vast herds of wildebeast and predators, while behind march the caribou, forever in motion, hunted for meat by city suppliers. Ungleaned seeds are frozen in the dusk, to sprout in the upcoming spring. Locally evolved life goes into hibernation deeper than any of the new arrivals can even imagine. 
And, if the visitors are humans, are there any who've left the city, to live a primitive existance as hunter gatherers beyond the citys reach? Stone tools (no wood, and a nomadic lifestyle doesn't lend itself to metal smelting) 
And what is the power source that keeps everything running? the original atomic system from the defunct starship? Windmills? If it were my planet, I'd know all that (and lots more) by now.


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## HieroGlyph (Jan 10, 2006)

I did wonder about the feasability study... somewhat. Without going into the maths or the climate of Lucius.

From what Marky asked originally about Arret moving without him knowing why... hmmm, well, I think Chris above has just reminded us that Lucius still needs to be somewhat Earth-like and stable in its orbit etc etc to allow 'us' to even contemplate setting up some city that outruns the sunset...

As to power sources and such, well, I assumed, being as we're within this particular section of this forum, that we'd have to make do with Nature 'as is'. i.e. There is no 'magic' anti-gravity... That stuff is for future tech. or the sci-fi area...


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