This pretty much describes the Venus in my Triplanetary setting, with the exception that all this has already occured by the dawn of the Space Age rather than being implemented by the year 3000. Its more fun to explore an unknown world after all, than one you created. so what we do is hide the creators and make them mysterious, let the player characters find out about them through their investigations, much as S.M. Stirling has done in his novels.
http://www.worlddreambank.org/V/VENUS.HTM
VENUS UNVEILED
A terraformed Venus, one thousand years from now--
by Chris Wayan, 2003-4
new? prepare for shocks - map - peoples and creatures - gazetteer - glossary - more worlds? Planetocopia!
Welcome to Venus! Venus as it will be, of course--the warm, living world we always imagined under the clouds, not today's inferno hiding under that mocking white veil. I've dated my portrait 1000 years from now, though Venus may not take that long to terraform. But it sure won't be as quick as Mars! There's shading, and cooling, and cleaning up the atmosphere, not to mention possible orbital tweaking... and the spin problem, and hailstorming (throwing a million Jovian icecubes at anything takes time!) Terraforming is like bonsai--patience, patience...
I've largely ignored human artifacts--towns, roads, dams, farms, factories, space elevators. Most science fiction uses other worlds as mere backdrops, but I want to take us out of the foreground and look at the land itself--Cytherian geography, climatology, ecology. This approach runs in my family. My mom paints landscapes, but she often quietly deletes all the works of humanity, to see what's underneath our buildings, wires and roads. Like her, I'm just a landscape painter... on a planetary scale. Except that living Venus will BE a human artifact--a work of art.
CONTENTS • Tour Venus! Regional maps and tours
• Portrait of Venus
• Climate zones
• What Venus needs ◦ Cooling
◦ The atmosphere
◦ What to do with excess CO2?
◦ Night and day
◦ Spin and seasons
• Suggestions? Email me!
TOUR VENUS
The heart of this site! Guided regional tours with maps, of...
•Ishtar's famous peaks, and its fertile, overlooked east
•East Aphrodite: Ulfrun's rainforest; Mt Maat, Atla, and huge Lake Fossey; the Jokwa Desert; Rusalka Bay; Dali Chasma
•Central Aphrodite: Diana Chasma, the ranges and deserts of Thetis, the great lakes of Artemis, and lush Cape Juno
•West Aphrodite: the alps of Ovda, green Cape Unelanuhi, and the tessera of Manatum and Hestia
•Eistla, Bell, and Tellus: out-Amazoning the Amazon
•Alpha and Lada, twin Earthseas
•Beta and Asteria's prairies and mountains, plus Hecate Chasma
•Phoebe's gulfs and tessera
•Themis's jungles, and the maze of Parga Chasma
•Dione and the Navka Archipelago, havens for strange creatures
•The South Sea islands, scattered and green: Imdr, Ishkus, Chuginadak, Puluga, Tonatzin...
SEE ALSO:
The GAZETTEER indexes and describes all the geographic features on terraformed Venus.
The glossary describes Cytherean terms like, well, "Cytherean."
The PEOPLES OF VENUS lists dozens of sentient species, their habits and habitats.
PORTRAIT OF VENUS
Later in this article I'll describe terraforming problems (Venus's heat, dryness, toxic atmosphere, spin), but frankly, all such talk is premature. We're still technological savages--we know what needs doing, but not how to do it! So why try? Let's treat the early, industrial phases of terraforming as a black box, and just assume we'll clean up Venus--somehow. My real interest is what comes next: Venus as a biosphere--as a place, a very big, beautiful place. This is a theme of this website in general; Dubia, the Earth with doubled C02, ignores the time of catastrophe to focus on what Earth'd be like once it settles down as a global hothouse. Same focus here: what Venus looks like as a world--not as an engineering problem!
As I've studied the radar scans and sculpted Venus's landforms, it's struck me how Earthlike they are--more than I anticipated from the comments of researchers, who I think are reacting to the current climate, not the landforms. Not just Venus's climate--the cultural climate here on Earth. Mars-mania is rampant, largely spurred by a historical accident: for centuries, when crude scopes and visible light were all we had, Mars made for fascinating viewing and Venus was a blank. But Venus is more Earthlike than Mars! It's closer in distance, size, mass, gravity, atmospheric density, tectonic activity. Yes, it's hot, and there are alien structures, and the absence of water-erosion has led to a pitted surface that'll abound in lakes and be short on river drainages, at least at first... but overall, Venus is beautiful--a complex geography that'll generate (in any terraforming model) fascinating continents with complex shorelines, islands, mountains, rifts, and lakes. In comparison, poor Mars is chunky, battered, lunar and brutal, with regions that'll never be viable under any terraforming scenario. But if any of Venus becomes livable, most of it will be. You'll never be far from water on Venus--or life.
Venus is an introverted girl. Unlike Mars or Earth, her surface is mostly shaped by inner forces, not weather or external impacts. The land looks stringy--ridges and arcs form tension lines connecting volcanic high points. It's as if a second veil lies over the real Venus--not of cloud, but of stone. What's going on inside isn't clear, but it's forceful, and not quite Earth's plate tectonics--nor Mars's cracking, static hot spots, and floods. The dominant theory at the moment postulates eons of deadlock and rising magma pressures, until, every half-billion years or so, catastrophic lava floods burst out, like Earth's Deccan or the Siberian Traps episode--but on Venus, these lava floods are worldwide, as if the planet reverts to its fiery birth. If true, such episodes may be triggered internally, or by large asteroid strikes.
But that doesn't explain the skein of arcs and ridges. My insticts tell me something rubbery is happening on Venus. I see elasticity everywhere--stretching, warping, squeezing till it corrugates. I'm a sculptor, used to flexible clays and acrylics, not a geologist--raised on plate tectonics, they tend to hunt for Terran-style plates or to reject plate tectonics utterly, some going so far as to deny large-scale crustal movements at all--just local spreading along rifts, and bubbling-up via coronas and volcanoes. I see wider movements! But not in plates--more like skin. Rubber tectonics... string cheese tectonics. (Io's not the only pizza!) The stuff's not just bubbling up under pressure. Sure, on the local scale (coronas, shield volcanoes, farras), vulcanism dominates, but some kind of large-scale stretching, bending or sliding is going on too. I just don't know what--or why.
Venus does have small Earthlike continents. But most of the surface lacks the sharp two-level nature of Earth or Mars, with their obvious seabasins and continents. Most of the landmasses I project are more like sea-floor rises and shallows, with no continental scarps. Now, Venus may have had an early oceanic phase, but the ancient shorelines are long gone, so I'm not restoring primal seas (as on Mars), just filling in modern lava-basins that may be not much older than Earth's present oceans.
Without fossil shores to guide us, sea levels are arbitrary. Mine are a few hundred meters higher than some terraforming proposals I've seen, but rather than try and re-create Earth with its sprawling continental interiors, I wanted to reveal as much of Venus's native topographic complexity as possible. The resulting coast is positively fractal--nearly every place on Venus is near water, and that's good for life.
My maritime Venus has a bit less dry land than Earth, but much more biologically usable land--fewer deserts or harsh continental interiors. And the seas will have wide, warm shallows--coral reefs? This Venus could sustain quite a lush biosphere--and it's a true sphere, unlike Mars's patchwork, pierced by stratospheric volcanoes and frayed by cold high deserts. Unlike Earth's, too! Pierced by polar caps, by Tibet, by the Old World desert belt, Earth's bio-"sphere" is more Martian these days than we think. It's been fifty million years since we had an unbroken biosphere. Swathed in thick air, Venus can be paradise--with enough water.
Besides, the impact of all those extra Jovian or Saturnian ice mountains will impart extra spin to Venus, which needs it. Even a modest rise in sea level allows a lot more ice-bombardment, since the surface area of the new sea increases as it rises. I think it's worth it. Still, if you like, you can build a Venus with a sea level half a kilometer lower (the basins are shallow, so that's about as low as you can go without getting mere chains of salt lakes, like Central Asia--desert country, please notice!) At this lower setting, you gain millions of square kilometers of land, at the risk of a harsher, drier climate. I've gone for quality, not quantity. Why settle for a hot Mars--or just another Earth?
CLIMATE ZONES
While I discuss the many terraforming options in detail below, it's likely Venus will have either a parasol or a swarm of shade-rings that cool the equatorial zone to something like our own subtropical temperatures. Why the equator? Just as the sun heats best at high noon, you get the most for your construction dollar by shading the high-noon part of the planet first. You can build a bigger parasol and shade the whole world if you want, but I've assumed a partial shade will do the job. So... a mild equatorial zone. Thirty or forty degrees north and south will actually be hotter, for the less shielded sun heats the surface to Earth-equatorial temperatures or more. The poles are cooler, drier zones, though not nearly as cold as Earth's. These warm and cool zones create two convection belts (Hadley cells) in each hemisphere, instead of the three on Earth (and terraformed Mars). Slowly spinning worlds tend to have larger cells anyway (Venus now has essentially one or no cells, while fast-spinning Jupiter has many tight belts) so I doubt that even a Venus with an Earthlike thermal gradient would have a three-cell system.
Zones of falling air, especially where the prevailing winds come from inland, can cause deserts on Earth, usually around 30 degrees north or south. In contrast, Venus, with its tropical Hadley cells reversed, will have its few deserts near the equator (mostly in Aphrodite). There will be twin torrid zones near latitude 40 or 45 degrees. Ishtar and Lada, nearer the poles, will be drier and cooler, though only the highlands will be truly cold. Lakshmi Plateau on Ishtar could glaciate--and even if it doesn't, the Himalayan-scale ranges around it will. Personally I'd like to avoid large icefields, though--they generate harsh weather, and unless we induce Venus to spin with enough tilt to provide seasons, snow country will STAY snow country, i.e. dead. Mars will have enough of that already! So let's keep the climate mild enough so Lakshmi ends up as an altiplano, cool, windy, but grassy, fed by snowmelt from the Maxwell, Freyja and Akna Ranges.
Venus has next to no axial tilt now, unlike Earth and Mars. If we can set Venus spinning at all, I suppose we could impart any tilted spin we want; but for the sake of this experiment let's honor Venus's axis, and see what happens. No tilt doesn't mean no seasons--on Venus, my best guess is that night and day, each about a week long, will be the primary seasons--evening will be fall-like, late night rainy and wintery, morning springlike, afternoon summery. The week-long nights, under most terraforming scenarios, will be many times brighter than full-moon nights on Earth--more like daylight around Jupiter or Saturn. (See NIGHT AND DAY below.)
Summary: my climate model has a mild equatorial zone under the shade of mirror-rings, torrid zones in the mid-latitudes where the shade-rings thin out, and dry, cool but not icy poles. The air is dense, and will transport a lot of vapor, but surface winds are weaker than Earth's, since rotation is slow and thermal gradients between zones are milder. Spin is retrograde, so currents, prevailing winds and Coriolis effects all run backward. Deserts will cluster on equatorial east coasts where dry air descends, while mid-latitude west coasts will be the rainiest places on Venus. (It all gives me an odd sense of deja vu, as I spin my Earth globe, looking at Oregon and England. Plus ca change, plus c'est la meme...)
Oh, well! Let's change subjects, now... AND tone. For the megalomaniac portion of our show, we now switch you to that engineer's delight, "Terraforming Fantasies." Hang on to your skepticism--you'll need it.
WHAT VENUS NEEDS
Terraforming Mars involves only one truly big project: adding a decent atmosphere. This isn't simple--free oxygen's needed, and Mars is nitrogen-poor, and you need enough greenhouse gases to warm the planet yet not poison animal life--like us. But except for nitrogen, the ingredients are there on Mars already. Even extra water may not be needed--certainly much of it is there already. The Martian orbit, axial tilt, rotation, geography, and level of tectonic activity are all acceptable right now.
But Venus has multiple problems which must be solved simultaneously -- at least by the standards of geologic time.
1.Cooling the planet. Clearly linked to this is:
2.Disposing of excess carbon dioxide. I don't say "carbon sequestration", since sequestering the carbon's not the only option, and the extra oxygen's a problem too.
3.Light and dark. I almost called this night and day, or the spin problem, but some solutions leave Venus with no clear or regular diurnal cycle, and some solutions don't even require Venus to spin.
4.Adding water. This is perhaps the simplest problem, but hailstorming Venus on the scale required would take time and does have risks.
COOLING
I've been debating half a dozen ways to cool off Venus. Solutions inevitably affect the other three problems!
1.Shade Venus with a very large parasol at the Lagrange point between Venus and the sun. Due to the large apparent size of the sun from Venus, and the distance of the Lagrange point, such a sunshade would have to be considerably wider than the planet! Expensive, and it doesn't help light the nightside, which other types of sunshades would.
2.Shade Venus with a large orbiting parasol. Several structures are possible, such as a strip half an orbit long, or an orbiting ring with alternating shades of night and openings for day, or multiple parasols in a ring. The total area of such sunshades is again very large. These are big engineering projects, and the planet's life depends on them. Kind of disturbing, isn't it? Still, orbiting parasols have the advantage that when a parasol is on the nightside it can function as a nightlight. If Venus's rotation remains slow, as it probably will, lighting the long night is a major issue.
3.Shade Venus with swarms of quite small orbiting mirrors (structures only 1-200 km across, or even less, instead of 10,000-100,000 km as in the first two proposals) which again function as multiple nightlights on the dark side. This is the first option that requires technology not much advanced beyond our own. A single ring of these would only shade Venus's equator, of course, so this scenario requires multiple tilted rings to cover all the lower latitudes at all points in Venus's year. It's the center of Venus's disk, facing the sun, that really needs a shield; the poles and dawn and dusk get no more insolation than Earth's tropics.
4.Shade Venus with even smaller, lower-tech devices: rocks, basically. Venus is too warm for ice-rings, of course, but any light-colored pebbles will do--plastic snowflakes? How about those clever little octahedral beacons that reflect light back to its source no matter how they're oriented? Well, whatever they're made of, each concentric ring must have a different orbital tilt, so that most of the surface gets some shade most of the year. I admit it sounds too complex to be stable, but why not? Unlike natural moons, these objects need not be heavy enough to perturb each other much. Light-pressure may be the main problem.
5.Don't bother to shade Venus! At least not much. Venus's present atmosphere (hot though it looks to my carbon-based readers) has a couple of admirable features: it reflects quite a lot of insolation, and it distributes its heat very evenly, from light to dark side, and equator to pole--at least solar energy isn't concentrated on the day-side equator. The only problem is the sheer amount of heat trapped. Yes, Venus gets more sun than Earth. But even high noon on Mercury is only about 670 K, and Venus gets less than a third as much solar energy--and if you spread it over the whole planet, not just the dayside tropics, it's less than a sixth. If we retain lots of thick white clouds (NOT of sulfuric acid, of course) to reflect a lot of light, and lower carbon dioxide levels enough, we might create warm but acceptable temperatures (around 300 K) all over the planet. If such an atmosphere alone wasn't enough, add some equatorial rings of mirrors (a simpler version of option 3). Since the dense atmosphere distributes heat so evenly, only the total insolation needs to be controlled, instead of a perfect, pole to pole shield. This is, I think, the simplest solution, if it's thermodynamically feasible, and if you don't mind a white, featureless sky, or at least a very cloudy one, most of the time.
6.Move Venus outward, using its excess atmosphere as reaction mass! This supposes cheap fusion power, huge, high-speed jets, and a lot of time, but then any proposal to terraform Venus requires larger structures and higher technology then Mars does. Where to put Venus? Either...◦Midway between Mars and Earth, about 20 million miles from each. That's nearly as distant as it is from Earth now--far enough to avoid perturbation problems. At this distance, insolation should be about right for a low-CO2 atmosphere several times Earth's density. No parasols, no mirrors... ideal.
◦Or pair Venus with Mars, much like Earth and Luna, but at a distance of 500,000 to a million miles. The tidal stress created by Mars in Venus helps replace the reduced tidal stress from the now more distant sun. Venus, being much larger, would induce in Mars tidal stresses comparable to Earth's, helping Mars to wake up geologically and belch CO2, thawing it out... Two for the price of one!
Moving Venus is a techno-geek's approach, and I feel a distinct reluctance to even explore such macho fantasies. But it might pay off: two viable worlds without elaborate shades or orbital mirrors. High initial risks (see NIGHT AND DAY #2, below, for some of them), but a safer, stabler result. Besides, think of those moonlit Martian and Cytheran nights, with a living, full-color world shining down... romantic, yes?
THE ATMOSPHERE
Venus's atmosphere gets a bad rap. One little flaw, and that's all you hear about! But if we can remove the CO2 from Venus's current atmosphere, what's left is not bad at all--three to four atmospheres of mostly inert gases. This thick residue has advantages over Mars or Earth's atmospheres:
•it distributes heat evenly. This is good, since we don't want scenic Ishtar to go all glacial on us. An even warmth is fine--just a bit less than now, please!
•a thick atmosphere held in by a deep gravity well is stabler. Getting the mix we want takes work, but if we do achieve it, we won't have the problems with air loss that leaky, low-grav Mars is prone to.
•Air pressure of three or four atmospheres, combined with slightly lighter gravity, makes wings much more efficient. Expect Cytheran life to be winged--even large creatures, like humans. Whether bioengineered or strap-on, angel wings may be the normal way to get around. Given the planet's geography--no matter how you set the sea level, it's going to be archipelagoes and shallow seas and continents full of lakes--flying and sailing, not roads, make the most sense. Dirigibles make sense soo--since their payload would be at least triple that on Earth, they'd be smaller and safer. Planes require less wing, too. Like low-gravity Mars, Venus will be a world of wings.
•thick air holds more water vapor. Winds on Venus are weak now, near ground level. We may need to force Venus to spin faster not just because we want a diurnal cycle, but to stimulate surface-level winds--storms have to get inland where rain's needed. But at least the air has the potential to transport enough moisture! In Mars's highlands, for example, the air's so thin that even saturated air just won't yield much precipitation.
•a thick atmosphere is an excellent UV shield, and with the sun this close, we need it. It's also a better shield against small and midsize meteors, though of course nothing can stop big impacts but high-tech intervention.
WHAT TO DO ABOUT EXCESS CO2? 1.Filter out inert gases (we want to keep them) but jet most of that carbon dioxide into the sun. This is a big engineering project, and risky (see NIGHT AND DAY #2 for details). But with fusion energy and the ability to build big enough, focused enough jets, it's not impossible, and might not even take too long.
2.Clathrates on the bottom of the new seas have been proposed, but how do you cool the planet enough to create seas while the CO2's present? Centuries of darkness, via a big parasol, till Venus freezes? Pelting it with Jovian icebergs will heat it up again, and every collision endangers the parasol. So we'd have to pelt it first, till the atmosphere's loaded with stratospheric water vapor (another greenhouse gas, unfortunately), THEN shade and cool it, and wait (years? decades? centuries?) for rain... precipitate the stuff... and pray it never breaks free! Would you want to live atop a CO2 bomb like that?
3.Diamonds! Built via nanotechnology, or large fusion-powered plants? This model has molecular assemblers constructing a sea-bottom stratum (1-200 meters thick) of diamonds or carbonates, comparable to our layers of limestone. Or toss the diamonds into space at an angle, adding more spin. If you can't bind all the oxygen into rocks (and I'll bet you can't--this isn't a wispy Martian or Terran atmosphere we're dealing with), jet the excess into space--it's not the hazard to other planets that migrant CO and CO2 would be (see NIGHT AND DAY #2, below, for risk analysis). It's true that any diamond scenario requires advanced factories working on a hellish surface, instead of nice comfy space work, but it has virtues, too--unlike the other models, the speed mostly depends on the scale and efficiency of a purely industrial effort. If a model was found that really worked, with vast numbers of self-replicating factories (at any scale, nano- to mega-) Venus could be cooled much faster than by sunshading alone. Indeed, without carbon dioxide holding in the heat, full shading might not even be needed. Hot oceans in a few generations? Sounds absurd, given at the scale of the project--but then, no one thought Earth's climate had catastrophic phase-changes, either. Wrong!
NIGHT AND DAY
I've been mulling over ways to create a diurnal cycle on Venus.
1.Hailstorm Venus--that is, pelt it with outer-system icebergs in cometary orbits at high speeds, and have these collide with the planet at low angles, imparting momentum. Part of the reason my Venus has sea levels set rather higher than some terraforming models is that I want as many icebergs as I can get, to impart as much spin as possible. I estimate that a third of a billion cubic kilometers of ice (about 1/15,000 of Venus's mass, and about the same mass as the atmosphere we want to vent or sequester), sent in as icebergs in fast enough orbits, would give us an acceptable sea level AND get Venus spinning about once every one to two weeks--not fast, but better than having nights that last months.
The problem with high-speed ice-bullets is that you mustn't miss and hit Earth--not once out of hundreds of thousands of strikes. A single hit, even at low speeds, would be catastrophic. At high speed (say 60-70 km/sec), the size of an ice mountain is effectively multiplied by ten, putting the energy of such a collision in the continental-firestorm category. Not something to play around with! And of course, to reach Venus (unlike Mars) the hailstorm must cross Earth's orbit. This is one reason the whole project won't begin for a long time to come. Ice ferrying must be absolutely routine--a mature technology with redundant safety layers. And you need an equally mature sociopolitical structure--no wars, no terrorists, no cost-cutting capitalists skimping on safety margins... In short, you need utopia--at least compared to our current barbarism.
2.One tempting if brutal method is simply to eject much of the atmosphere at very high speeds from an angled jet, forcing the planet to spin AND getting rid of unwanted CO2. Mt Maat, as high as Everest and exactly on the equator, is the logical spot for a fusion-powered jet, though it may be a wee bit, um, active. Still, siting giant fusion jets atop live volcanoes shouldn't faze anyone who's gear-headed enough to turn Venus into a rocket-powered pinwheel for a century or two. No, that's not the real problem. Where's all that high-speed CO2 go? To give us enough reaction to spin Venus, it has to go fast, so even if you fire it sunward, much of it will spiral out to Earth's orbit and beyond, filling the plane of the inner Solar System with a thin cloud of carbon, oxygen, carbon monoxide and CO2. We're ejecting nearly 100 times Earth's entire atmospheric mass--that's about THREE HUNDRED THOUSAND TIMES the CO2 content of our atmosphere. So, if even a millionth of the soot spewing from Venus's smokestack drifts into Earth's gravity well, our CO2 levels would rise dangerously--and that's on top of industrial warming. Why terraform Venus by veneraforming Terra?
This also limits proposal 6 above, in which Venus gets moved outward using its atmosphere as reaction mass. The most efficient way to do this is to jet off the atmosphere behind the planet, in its orbit. But this again would leave a large plume of CO2 spiraling out toward Earth. In both cases, the only safe jet would be a single one pointing at the Sun--less efficient and not imparting any spin. Even this assumes dumping carbon on the sun's surface doesn't affect its light output, magnetic lines, sunspot patterns, or flaring. Yeah, let's shoot a giant fire-extinguisher at the sun and see what happens! Don't you just love engineers?
Still, the angled-jet scenario is so tempting because it gives us twice the spin that simple hailstorming does--you might even get Venus turning once every three days--so fast that a high-noon parasol and a midnight mirror could make a 24-hour light-and-dark cycle, simplifying things for any number of Earth species. There's an emotional factor, too: "let's make that damn CO2 do something useful for a change!" But that doesn't justify the risks, does it?
3.Let Venus's spin stay about the same--that is, very slow--but build a parasol out at the La Grange point, louvered like a Venetian blind, opening and shutting to create day and night. This seems complex and prone to wear and tear. Simpler: let the shield be a rotating shape that allows a lot of sun when it's edge-on and very little when it's full-face to Venus, or build a spinning flower with petal-shades causing local night, and missing petals for local day.
But a La Grange shade won't light the long night. A mirror for the night side, placed in the other La Grange point, high above midnight, would have to be several times Venus's size--that point's a long way out. And the shadows of Venus and the sunside parasol would reduce its efficiency--a large ring would be more efficient than a disk. A better solution might be a smaller ring-shaped mirror, a mere 1.5 times Venus's diameter, floating closer to the nightside. Build it light enough and Venus's gravity could be offset by the intense light-pressure on the mirror. Again this would require constant supervision, but in theory at least, it could be made to float in permanent balance. Besides, it'd look pretty, wouldn't it? Of course, such a proposal is only viable after the death of capitalism... or the damn thing would be covered with ads. Come on, you know it would.
4.A large orbiting sunshade or sunshades, in a 24-hour orbit (around 40,000 km out) would be an even more massive project, and big orbiting mirrors, with low mass compared to the light pressure on their surfaces, might be prone to drift or orbital decay. Though, surely a civilization capable of building them could maintain their infrastructure... right? Our own build-it-and-forget-it society is not encouraging in this regard! Still, such 24-hour mirrors do have the advantage of doing three jobs efficiently without moving parts--cooling the dayside, lighting the night, and creating a Terran diurnal cycle regardless of Venus's spin. Plus, a great silver arch in the equatorial sky would be beautiful--rather Saturnian, if harder-edged. It's just a big investment. We're talking about an arc of mirror over 100,000 kilometers long!
5.The simpler orbital-mirror program described in COOLING 3, with multiple, tilted Saturnian rings, not at "24-hour" distances but only a few thousand miles out. Each disk-mirror, 1-200 km wide, would make an extremely bright "full moon" in the night sky, though of course they'd wink out around midnight as they pass through Venus's shadow. Sunlight around Venus is nearly twice as intense as on Earth, and of course the albedo of a mirror is far higher than a moon of the same diameter. A sky dotted with many such moons could, I estimate, reach 1-4% of daylight levels on earth--like full daylight on Jupiter or Saturn, and a thousand times the brightness of our full moon. It'd be a shifting, forever changing dawn/dusk light, perhaps a bit like our Arctic. Not bad for technology we could almost deploy today!
6.Light up the night on the ground. This sounds absurd, but I live in San Francisco, a city famous for its fogs. When there's a low-lying cloud layer, the city lights can cumulatively light the night sky much brighter than moonlight--and they're not even trying! With cheap fusion power and lights aimed upwards at the bottom of Venus's clouds, daylike illumination could be achieved. It requires a permanent cloud layer, AND it produces waste heat we don't want, but it's still worth noting. Brute force as a last resort! (But wouldn't Frank Herbert have added "...of the incompetent"?)
SPIN AND SEASONS
The most spin I can manage, so far, is a slow Cytheran day about two Earth weeks long, which would also be the equivalent of Earth's seasons, warm and cool, dry and wet. The fourteen-day climate cycle might run:
1.SUNDAY: when the sun rises, of course! Low, dramatic light all day; morning rains (if any) break up into scattered showers. Tricky winds as the warm front of day sweeps across the world.
2.MONDAY: early spring. Flowering in response to the night rains. Low golden light. Mild temperatures. Clouds and showers patchy at most.
3.TUESDAY: spring, warming, clouds clearing. Bright sun, though little brighter than Earth's; at lower latitudes the rings or moonlets tame the sun's brilliance artificially.
4.NOONDAY: clear, warm, bright, but with constant eclipses (or a smoothly dimmed sun, depending on optimal moonlet-size).
5.THURSDAY: the Cytheran summer, the hottest part of the week. Dry in most regions, though the two Amazonian belts may have thunderstorms.
6.FRIDAY: summery, but cooling toward fall by noon. Thunderstorms fade in the torrid zones.
7.SETTERDAY, when Irish setters fall from the sky. No, no, when the sun sets. Low, dramatic light. Many flight-accidents due to glare and shifting winds from the cool night-front chasing sunset around the world.
8.DUSK: the sun goes down, the sky flames--and the display lasts all day, changing hourly. Mild but variable temperatures.
9.EVE: a mixture of dim blue horizon-light and bright ringlight--total light rivals good indoor lighting on Earth, with colors brightly visible. Cooling.
10.RING: maximal ringlight, as bright as noon on Jupiter, intermittently blocked by increasing clouds, even some showers. Cool to cold (for Venus).
11.YULE: midnight, and theoretically the darkest night, since the shadow of Venus on its rings passes overhead; moonlets or rings turn reddish and dim as they enter the Shadow, picking up heavily filtered sunset light. Rain in many regions. Yule will not be 24 standard hours long, though all the other days are. Kim Stanley Robinson has suggested for Mars that we keep Earth hours, minutes and seconds, and accomodate the slightly longer day by a time-slip after midnight. On Mars it's only 37 minutes, but on Venus, depending on the spin that's finally achieved, the Cytheran Timeslip could be substantial. Yule might only be 12 hours long, or 40--or not exist at all.
12.RAIN: steady rain in many regions. Stormclouds make this the darkest night in wetter regions--only a few times brighter than a clear full-moon night on Earth, with colors dim, though still visible of course.
13.WITCH: the thirteenth day in the cycle--the witching hour. Rain in many regions, but the sky may start clearing late in the day. Predawn light begins to supplement bright ringlight, making the brightening even more noticeable. If clear, Witch is as bright as Ring or Eve--like daylight in the Jovian system.
14.DAWN: an all-day spectacle--turquoise light slowly drowns the white rings, and then green, gold, salmon, and fiery magenta fill the sky. Toward midnight, the first rays of direct sun.
It must be obvious by now that the "days" of such a calendar function more like hours on Earth or Mars--as local timezones sweeping round Venus. It's always Tuesday somewhere on Venus--all fourteen days are always happening simultaneously. On the other hand, ten o'clock happens all over Venus at once. When you cross timezone-lines, you adjust your calendar by one day--not your watch.
Longer intervals will likely be measured in these fourteen-day cycles (let's call them months) and 225-day years of sixteen months each--though, perhaps, since Venus's year doesn't affect its seasons much, people may measure long time intervals in Terran years for convenience. Or Martian or Jovian years--we shouldn't jump to conclusions about who'll terraform Venus, or be the cultural center of the Solar System a thousand years from now!
