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acrsome
12-15-2013, 12:22 PM
Howdy, All.

As I mentioned elsewhere (http://www.cartographersguild.com/member-introductions/25461-another-new-guy.html) my pet project is going to be a terraformed Venus. I plan to use it for an ultra-low fantasy (no magic) campaign set a few millennia after a cataclysm. Here's a preview:

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This is a USGS topo map of the planet with a sea mask and 5-degree lat/long lines superimposed, Mercator projection, and it only goes to 57-degrees north and south. (At the equator a 5x5-degree quad is roughly 328 miles square, so almost 108,000 sq miles- just a bit bigger than Colorado.) It also is compressed quite a bit so that I could post it here- the original is over 27000 px across. I'm going to use this to guide my work on smaller regional maps. I'll also use this to figure out climate.

As a bit of a warning- It'll probably take me years to get any work done on this, so don't expect updates often.

Here are the prevailing winds, before I take into account the continents:

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If it looks backwards, remember that Venus rotates the other way- the sun rises in the west.

foremost
12-15-2013, 02:37 PM
Sounds like a very neat idea :)
Excellent detail of all the little islands, looks like back-breaking work.
Are those mountains or swamps?
No pressure on updating quickly, but when you get things done, please do let us know.

FM

acrsome
12-15-2013, 02:57 PM
They are mountains (real planetology). I'm not planning on going with the classic "Venus as a swamp-planet" motif.

And on another forum someone just pointed out that I could rotate the map 180 degrees to disguise the fact that the sun rises in the west, to confound those who might otherwise recognize it. Hmm.

Overview:

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Prevailing Winds:

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I'll presume that the Powers That Be decided to just designate east as "the direction the planet spins," and north is "to your left when facing east," etc. The actual magnetic character of the poles really should have little to do with such things.

gilgamec
12-17-2013, 02:13 PM
As part of the terraforming process, has Venus's rotation been sped up? Otherwise, a single day will last so long (240 Earth days or something) that I'm not sure that you can use Earth-based climatic theory. For example, the "day side" of the planet would be receiving light and heat for (Earth-)months at a time, so pressure zones that would form would be more based on continent/ocean size than axial inclination.

acrsome
12-18-2013, 12:20 AM
Yes, I'm proposing that the rotation is sped up. 116-day solar days are pretty unworkable. Speeding up Venus's rotation will deform it into a more oblate spheroid- it will bulge at the equator, causing new rifting perpendicular to the equator. This will be roughly 40 miles of extra circumference, so I figured I'd add a new 2-mile rift every 20 degrees or so, plus lesser ones where needed. (This actually gives me a way to drain some basins that would otherwise be inland seas.)

I'm also giving it 20-degrees or so of axial tilt, to generate seasons.

What I haven't decided is whether I'll keep Venus in the same orbit with some sort of sunshade or if I'll move it to a new orbit. Keeping it where it is has the advantage that I need not add a moon to have appreciable tides- solar tides would be about as strong as Earth's lunar tides. Not having a moon probably means more perturbation of axial tilt, but that's an issue on scales of tens of thousands of years. And a Venus year would still be only 224.7 days.

OTOH moving it to a new orbit avoids the need for constant station-keeping on the part of a sunshade. And, heck, if my planetary engineers can move Venus then they might as well snag Triton as a moon for it. About 1/3 of Triton's mass could provide volatiles for the terraforming, too (mostly nitrogen and water), leaving a slightly smaller moon to orbit as a satellite. It would also lengthen the year. Options include moving Venus into a binary relationship with Earth (which would require ejecting the Moon to avoid the N-body problem), moving it into a binary relationship with Mars, or slipping it into its own orbit midway between Earth and Mars. (I worry that this would do something terrible to the orbital resonances of these planets, though.) It cannot be placed on the opposite side of the sun from the Earth, as L3 is unstable. So are L4 and L5 unless one body is much larger than the other, which would not be the case here- eventually they would collide or one would be ejected.

I'm tending towards the position that if my engineers can spin Venus and give it an axial tilt, then they are probably capable of moving it to a new orbit if they feel like it. But I'm not sure what I want for my campaign.

Anyway, here are some initial climate maps:

January

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The equator and 30-degree parallels are shown. The north and south map edge are at 57-degrees. The reddish pseudo-equatorial line is the ITCZ. Major landmasses are labeled.

July

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I'd appreciate if you all could point out glaring errors before I start scribbling a few hundred windsock arrows over the maps. :)

I used The Climate Cookbook (http://jc.tech-galaxy.com/bricka/climate_cookbook.html) and PhysicalGeography.net (http://www.physicalgeography.net/fundamentals/7p.html) as guides.

Oddly, I have in some ways recapitulated Earth on these maps- you can see how I have a North and South America, a Eurasia, etc. Thus I leaned on the latter website a lot. The wild card is that my Eurasia sits approximately smack on the equator, so if anyone has any ideas about that I'm listening. Looks like monsoons in Thetis and southwest Ovda?

Also, I can't quite figure out what to do about Alpha and Astkhik. Their land area is probably too low to have a real continental effect, so I think that I perhaps should do the opposite of what I show here, because they are in the equivalent of my Northern Pacific, which looks like it has a honking big low in January and a mellow high in July.

foremost
01-10-2014, 10:55 AM
Again, looks like this was a lot of work, tons
of little islands all over your map. Going to
make for a lot more work when the project
progresses. It's obviously been a few weeks
since you updated, so I hope you are still
going.

My question would be "Why is the heat-band
not directly on the equator?" Maybe this is
as it should be, and I'm interested to know
why.

Water takes a longer time to heat up or cool
down than land does, and it's also going to carry
some wind currents along with it. The temperature
should also fluctuate throughout the seasons. Does
Venus have seasons?

Anyway, the coastal areas will have more balanced
temperature, thanks to proximity to the water. Inland
areas might be bone-dry and wicked hot as well.

I'm no expert on this, and if you have information
from those websites you mentioned, please share!

Neat project, hope you continue.

rgcalsaverini
01-12-2014, 05:11 PM
Great to see a map with such realism! I tend to rush to drawing before settling some necessary things before. I will be following this eagerly!

Nathan
01-17-2014, 05:33 AM
Oh ! I really like that !
Impressive !

Caenwyr
01-17-2014, 07:58 AM
Great to see a map with such realism! I tend to rush to drawing before settling some necessary things before. I will be following this eagerly!
Seconded! No patience whatsoever here... though I really should work on that! My sincerest compliments to your perseverence, acrsome!

acrsome
03-25-2014, 09:17 PM
Yes, I'm still working on it. Exactly two days total since my last post, but I warned you all about that. Careers suck sometimes...

@foremost: Those aren't "heat bands", they are high- and low-pressure zones. And the ITCZ is just sort of a line near the equator with equal pressure north and south of it. I can't explain it in a pithy manner (especially since my own grasp of it is tenuous at best). If you're interested check out those websites I listed.

Venus terraformed the way that I'm proposing will indeed have seasons. It's been given more axial tilt, and its spin has been increased.

Speaking of which I wasn't happy with the previous climate maps, so I re-did them making some different assumptions. I also added winds and currents. I'm ready to start working out Koppen climate zones soon.

So, yellow are high-pressure zones, blue are low-pressure zones, and the green arrows are prevailing winds:

Here is July:

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Here is January:

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Here are currents, hot cold and indifferent:

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Recall that "hot" and "cold" are relative. I.e. a warm polar current can be colder than a cold equatorial current.

EDIT-- Does anyone have a nice 1000m contour map of the world or of North America, so that I have something to compare to while working out climates? My Google-Fu is failing me.

EDIT-- I decided that I don't like my first world-spanning map (the file size is simply too big to work with) so I'm currently working on re-doing it as eight regional maps instead. Luckily, I found a decent set of USGS base maps that includes the poles, so now I can cover the whole planet. Which is nice, because Ishtar Terra is damned interesting. I've also been struggling with Koppen climate zones, and I'm getting frustrated. I need the climate worked out so that I can decide which basins will be endorheic and which will be inland seas or lakes, etc. But some of these basin seas might be big enough to affect climate. Grr. It looks like most of northeast Aphrodite will be a Sahara-equivalent, and there are a few areas with true monsoons in Manatum and in that large bay at the west end of Thetis.

So, more will follow... eventually.

acrsome
04-19-2014, 10:20 PM
Here are some initial thoughts on Koppen Climates. Lines of latitude are in 15-degree increments (this is a Mercator projection that only covers to 57-degrees north and south).

Frankly, a map of biomes like the Hodridge scheme or like this (http://upload.wikimedia.org/wikipedia/commons/e/e4/Vegetation.png) is probably more practical and useful than Koppen climates, but it seems to be traditional to do the Koppen thing. I'll probably make a biome map later, and the Koppen climates will help me on that.

There are a lot of landforms that don't really have perfect analogues on Earth, so I made a lot of stuff up. For example, my huge Himalaya-like mountains are on the equator, so I used the equatorial Andes as a model for them somewhat, and made some SWAGs. (Actually they're not quite Himalaya-scale; the really tall mountains are in Ishtar.) A lot of my continents don't have a large north-south mountain range as in the Americas or Himalayan rainshadow like Asia, so I'm not sure how the east-coast and west-coast climates meet in higher latitudes without one.

My large Amazon-like Af rainforest is in eastern Ovda, since that's the only large chunk of tropical land on an east coast right on the equator. (Equatorial Phoebe is small in comparison.) I made eastern Atla somewhat similar, though.Generally, since so much of my land is in the tropics there is a LOT of Af, Am, and As.

So, I guess I'm making a jungle/desert world...

Ulfrun/Atla is a rough analogue of sub-Saharan Africa. Thus, that enormous BWh desert largely covering Zhibek and Artemis is a Sahara-equivalent. (There are no large mountain ranges to keep that desert from just cutting all the way across the continent.)

Eistla will be an Australia-equivalent. I may change the Umay-ene climate a bit and make it my Madagascar biome.

There is no good Europe-equivalent with an aberrantly high-latitude Cwa climate, unless it's Hathor and western Themis... but I was going to make Themis/Phoebe my South American biome, and make Beta my North American biome. (Ishtar is probably more like a Canada/Scandinavia bastard child.)

The only true India-like monsoon is that bit in western Thetis; the other Am climates technically meet criteria- like most of the the Amazon- but aren't the intense and brief raging torrent of the Indian Ocean monsoon.

This is all just preliminary, to help me make other decisions such as which low spots to fill as lakes and which to leave as endorheic basins, deciding where the big rivers will be, etc. Nonetheless, if anyone has any criticisms, fire away. My eyes were crossing in a lot of spots, so I'm sure that I have some egregious idiocy here, somewhere.

I'm still working on my newer maps that will show the poles as well. This is important, because there is a lot more of Ishtar down there, and that might end up being an important place. (I have to think of new names for these landforms...)

I also found GTDR data from the Magellan mission, which is topographical data on Venus. I thought I'd run it through some manipulations in Wilbur when I get a chance and see what pops out. Unfortunately, one pixel is 4.6km, so it isn't terribly detailed, and there are a lot of holes and artifacts in the data, but I still think it can help me figure some things out.

Hmm... I guess that I have a Wilbur question... given data like that can Wilbur for instance double the number of pixels (to 2.3km/px) by extrapolating elevations or somesuch? (I have yet to download Wilbur- I have to dual-boot some sort of Windows on my laptop, first.) I wouldn't mind trying to do a nice job with Wilbur on some small area, like Tellus or Eistla, or maybe Beta. (I understand that Wilbur works best on smaller scales.)

After sangi39 mentioned this inspired study (http://www.bristol.ac.uk/university/media/press/10013-english.pdf) on his Yantas thread I started looking around to see if there was any way I could run my world through the HadCM3L climate model, but I don't think that there is. Unless, of course, someone here happens to work for the UK Met Office or the Hadley Center... :)

A final point: I was going to name this world Sypherion, that being a fictional cognate of cytherean, which means "of or regarding the planet Venus." But then I found Max's map of the city of Yphyrion, and now I don't feel so clever...

sangi39
05-06-2014, 11:08 AM
So I've been meaning to reply to this for about 16 days now, but luckily it's all praise, since I don't feel like I know enough to point out any errors lol. Looking at your map and the Koppen climate map for Earth, though, has really made it clear to me that my climate map for Yantas was pretty damn wrong :P I mean I don't have tropical rainforests at the poles, but I seem to have been overly simplistic in dealing with certain climate zones :P

acrsome
05-07-2014, 09:28 AM
Oh, I just think that your climate map was a roughing-in, so to speak. As if you made a map with the suggested latitudes taken very rigidly, and painted in as bands, to use as a guide. I thought that's a great idea (and probably sufficient for any fantasy mapping needs). So I stole it :) and did something similar, but then looked at the real-world Koppen maps on Wikipedia and did some fleshing out.

I spent a lot of time obsessing over the descriptions on the Wikipedia page.

sangi39
05-08-2014, 01:40 PM
Oh, I just think that your climate map was a roughing-in, so to speak. As if you made a map with the suggested latitudes taken very rigidly, and painted in as bands, to use as a guide. I thought that's a great idea (and probably sufficient for any fantasy mapping needs). So I stole it :) and did something similar, but then looked at the real-world Koppen maps on Wikipedia and did some fleshing out.

Huh, how very dare you :P I do like the whole idea-sharing thing that goes on here at the Cartographers' Guild :)


I spent a lot of time obsessing over the descriptions on the Wikipedia page.

Yeah, I spend a couple of days on Wikipedia, editing my climate map as I went along, but then I got annoyed and deleted the edits :P

Pixie
05-08-2014, 07:21 PM
That's the problem with keeping the post a WIP when it comes to climate map. You spend so much time looking at it, adjusting and dealing with too many variable (rain, temperature, seasonality, high-low pressures centers, ocean currents, prevailing winds), that you end up unable to

1. explain the reasoning (if it is your map)
2. understand the reasoning and suggest improvements (if you are the lurker)

acrsome
05-13-2014, 04:17 PM
As with, I suspect, most of the larval-stage cartographers who end up here I have discovered Wilbur (all hail Waldronate). I dug up some Magellan data on Venus topography and fed it through, dealt with some annoying artifacts (thanks Redrobes), and then some more artifacts, etc. Here are a few preliminary views.

First, Thetis, Ovda, and Manatum:

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The snow line is set at about 14000 feet, by the way.

Next, here's one that shows that southern continent (Ishtar) and the south pole:

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The pole is obvious because it was missing from the Magellan data and I had to clone some in- very inexpertly- and it shows. It's that first darker ocean basin below the high mountains on the continent.


Since I can use this data to do all sorts of neat stuff with Wilbur, I think I'll use it instead of my hand-traced version from the scanned USGS maps. I'm still trying to figure out how to export images from Wilbur. Obviously, I managed to export these, but every time I try to export an equirectangular image- or actually anything not orthographic - it gets truncated at the edges. This happens even when I set the exported image's size to my map size. Grr.

Once I deal with a bunch more little artifacts I'll start exporting it to GIMP, making sea masks, etc.