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When it comes to mollusks, people talk a lot about the charismatic giant squids and giant clams (and for good reason!), yet, to my mind, these are not the strangest—or even the most elusive–giant mollusks. Scientists have long sought a very different creature—the giant shipworm (Kuphus polythalamia)—which they knew from its bizarre meter long tubal shell. Yet despite the fact that such shells were (relatively) plentiful—marine biologists never found a living specimen…until this spring, when internet clips revealed footage of people eating huge shipworms in the Philippines. Researchers were thus led to a remote lagoon in the archipelago where at last they discovered living giant shipworms flourishing in the foul muck. What they then discovered was the most shocking thing of all…

But first let’s provide some context. Shipworms are bivalve mollusks (like clams, oysters, and mussels) which eat wood–a surprising amount of which finds its way into the oceans. Wood is extremely difficult to digest, since it contains lignins, cellulose, and such like tough organic polymers. Shipworms digest wood the same way beavers and elephants and termites do—with help from symbiotic bacteria. This made shipworms the bane of pre-industrial mariners (who counted on intact wooden hulls in order to remain alive).

But shipworms are small, and the giant shipworm is…giant. The fact that the giant shipworm is an insane 130 cm long cylindrical clam with a gun metal blue body and obscene flesh gills which lives in a huge calcium tusk the size (and shape) of a baseball bat is not at all the strangest aspect of the creature. What is most odd about this mollusk is how it eats: it doesn’t. The foul anaerobic slime at the bottom of that lagoon in the Philippines is rich in hydrogen sulfide from decaying organic matter.

The giant shipworm doesn’t eat this decomposing matter (indeed, its mouth is all but vestigial). Instead it has bacteria in its gills which live upon hydrogen sulfide. The giant shipworm survives off of the byproducts of this bacterial respiration. It grows huge off of toxic gas. This strange metabolic cycle is of great interest to scientists for what it reveals bout symbiosis, adaptivity, and metabolism. Perhaps someday it will be useful as well. Maybe future generations of explorers will love giant shipworms for their ability to live on waste product gases just as much as vanished generations hated shipworms for eating ships.

Humankind is always fixating on the Moon and Mars as the most likely spots for the first space colonies, but there is another crazy possibility.  Aside from the Sun and the Moon, Venus is the brightest object in the night sky.  Earth’s closest planetary neighbor, Venus is a veritable sister planet with extremely similar mass and volume.  Because of its  size and position in the solar system, a great deal of early science fiction concentrated around Venus.  Dreamers and fabulists posited that beneath its ominously uniform cloud cover was a lush tropical rainforest filled with lizard people and pulchritudinous scantily clad women (the fact that the planet’s Greco-Roman name is synonymous with the goddess of love and beauty seems to have influenced many generations of male space enthusiasts).

Maybe we should head over there and check it out…

Alas, the space age quickly dispensed with mankind’s sweaty-palmed fantasies about life on Venus.  In 1970 the Soviet space probe, Venera 7, was the first spacecraft to successfully land on another planet (after a long series of earlier space probes were melted or crushed by atmospheric pressure).  In the 23 minute window before the probe’s instruments failed, the craft recorded hellish extremes of temperature and pressure. The temperature on Venus’ surface averages around 500 °C (932 °F), (higher than the melting point of lead) and the pressure on the ground is equal to the pressure beneath a kilometer of earth’s ocean.  The planet’s surface is a gloomy desertlike shell of slabs interspersed with weird volcanic features not found elsewhere in the solar system (which have strange names like “farra”,” novae”, and “arachnoids”). Additionally the broiling surface is scarred by huge impact craters, and intersected by immense volcanic mountains (the tallest of which looms 2 kilometers above Everest). The tops of these mountains are covered with a metallic snow made of elemental tellurium or lead sulfide (probably).

A photo of the surface of Venus from Venera 13

The atmosphere of Venus is a hellish fug of carbon dioxide which traps the sun’s energy in a self replicating greenhouse gone wrong.    Above the dense clouds of CO2, the upper atmosphere is dominated by sulfur dioxide and corrosive sulfuric acid.  Once Venus may have had water oceans and more earth-like conditions, but rampant greenhouse heating caused a feedback loop which caused the planet to become superheated billions of years ago.  Without an magnetosphere, solar winds stripped Venus of its molecular hydrogen (yikes!).

Artist’s Impression of the Surface of Venus

Thus Venus does not initially present a very appealing picture for colonization! Yet the planet’s mass is similar to Earth (and humans’ long term viability in low gravity is far from certain).  The planet is closer than Mars and windows of opportunity for travel are more frequent. Fifty kilometers (30 miles) above the surface of Venus, the temperature is stable between 0 and 50 degrees Celsius (32 to 122 degrees Fahrenheit).  Light crafts filled with oxygen and nitrogen would float above the dense carbon dioxide.  Today’s visionaries and dreamers therefore have stopped thinking of tropical jungles and envision instead a world of Aerostats and floating cities.  Although the rotation of Venus is too slow to craft a space elevator, the flying colonists of Venus probably could build some sort of skyhook with existing or near future technology.  Such a hook could be used to lift raw materials from the surface to manufacturing facilities in the skies.  As more aerostat habitats were built, the colony would gain manufacturing strength, safety, and a greater ability to alter the barren world below (increasingly overshadowed by flying cities and hovering countries).

Imagine then a world like that of the Jetsons where the surface was unseen and not thought about (except by scientists and industrialists).  Floating forests and croplands could be assembled to mimic earth habitats and provide resources for a bourgeoning population of Venusian humans.  Skyships would cruise between the flying city states dotted jewel-like in the glowing heavens.   Over time these flying habitats could be used to alter the planetary temperature and shield the desolate lands below.  Humankind and whatever friends and stowaways came with us would finally have a second home in easy shouting distance of Earth.    How long would it be then before we took steps to take Earth life even farther into the universe?

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