September 23, 2020

Life on Venus?

         There has been much recent excitement over the report that scientists have discovered levels of the chemical phosphine in the atmosphere of the planet Venus.  This is exciting because phosphine is produced by microbes and thus could be an indicator of life on Venus or, to be more specific, in its atmosphere.  If you haven’t seen the news, you can read about it here.  Of course the idea of life on other planets is also of great interest in the field of speculative fiction, so today I’m leaping straight from the cautious scientific possibilities of hypothetical microbes to imagining complex and potentially intelligent alien life.
        First, a quick review of how sci fi writers have imagined Venusian life in the past: Venus is often called Earth’s twin, and in the early days of science fiction Venusians seemed as plausible as any other space aliens.  First Venus was generally understood to be tropical jungle and/or largely oceanic, then it was presumed to be harsh desert, in both cases with the appropriate fauna.  I haven’t read or seen any of these myself, but according to various sources the Venusians may include creatures that are a blend of elephants and horse-flies (Fred. T. Jane, 1897), spider-like shelks (Charles R. Tanner, 1930’s), serpent or lizard people (Lumley and Lovecraft, 1930’s), green humanoids (C.S. Lewis, 1940’s), giant frog-like amphibians (Captain Marvel, 1940’s), Aphrodite-worshipping fairies (Wonder Woman, 1942), grinning cones (“It Conquered the World” 1956), three-eyed chefs (“The Twilight 
Zone” 1961), animated plants (Arthur C. Clark, 1960’s), three-headed green Fearians (“Challenge of the Super Friends” 1978), horse-sized bees (Jacqueline Susann, 1979), snakes with sulfur blood (Ben Bova, 2000), or many other variations, especially of humanoids and dinosaurians.  It seems that a very high proportion of Venusians are either driven to extinction by humans, or do their darnedest to drive humans to extinction.
        Sci fi is concerned with exploring big questions such as war and peace, relationships with the “other,” evolution and extinction, what it is possible to do and whether it is right to do something just because it’s possible… and of course, sometimes it’s also simply about telling a rip-roaring adventure yarn.  In any case, when writers imagine aliens, it’s about the story they’re trying to tell, influencing whether the aliens are more or less intelligent than humans, more or less aggressive or warlike, more or less enlightened, and so on.  But I’m not telling a story here, so I’m just thinking about what sounds cool to me!  If life were to exist on Venus, it would probably have to exist in the particular level of the atmosphere where the temperature and pressure levels are not quite as extreme, but even there the atmosphere is full of sulfuric acid.  Any life in this “cloud deck” would clearly have to be quite different from life on earth.  Again, however, I’m just imagining what sounds cool, so I look at these various factors and imagine… jellyfish.  If life had actually evolved in the oceans of Venus before runaway greenhouse effect turned the planet’s surface into a searing hot hellscape, why not have aquatic life adapt to move up into the atmosphere?  And what aquatic life would be more suited to floating up into the clouds than jellyfish?  Here are a few fun facts about jellyfish that make them seem particularly plausible as candidates to evolve in the oceans of Venus and then continue adapting as conditions there changed.
   * Jellyfish are the oldest multi-organ animals on earth, making them basic enough to evolve in the first place, with plenty of time to evolve further.
   * Jellyfish are the most energy-efficient swimmers of all animals, so they need relatively less energy to get around.
   * Jellyfish have a variety of ways to reproduce, including asexual budding and sexual combining of egg and sperm; and different species have all manner of variations in their life stages.  All this variety makes it more possible that some version might be adaptable to any of the changing conditions Venus might throw at them.  Whether they need to anchor or swim free, protect developing polyps or broadcast them through the ocean, there’s a jellyfish that does it.
   * Some jellyfish have mutualistic algae growing inside them, and others have symbiotic relationships with single-celled planktons, giving them yet more ways to collect and process energy and nutrition, and yet more possibilities for different ways to interact with their environment.
   * Jellyfish often benefit from disturbed ecosystems, such as lower oxygen, higher salt, or turbid water, which implies that they would be more likely than many other species to survive and adapt to catastrophic changes to their environment on Venus.
        So, imagine a world that is a narrow band of cloud encircling a planet.  Imagine not just your most stereotypical image of an Earth-ocean jellyfish, but every sort of ecological niche filled by the descendants of jellyfish-like creatures.  Huge balloons the size of whales could drift through the clouds dangling kilometers of winnowing tentacles as they feed on vast swarms of single-celled creatures or tiny jellies only a few millimeters in size.  Other jellyfish could live in the lowest band of the cloud deck, scavenging the creatures that lose their buoyancy and sink.  There could be swift-moving jellyfish, having bells that can expel spurts of gas like a deflating balloon, sending them shooting through the clouds either as predators or as prey.  Various senses could have evolved, including sight, sound, and smell, but also different ways of perceiving their world, such as sensing heat or electrical currents or vibrations.  There 
could be jellyfish that evolved ways to move and control their tentacles more precisely, so that they might be capable of all the physical manipulation made possible for humans by upright stance and opposable thumbs.  There could be jellyfish large enough that other sorts of jellyfish build cities inside them, forming symbiotic relationships as island city-states floating through the atmosphere.
So that’s what I’m imagining.  What about you?  If there were to be life on Venus, what do you imagine it could be like?  (You can see what I came up with here.)

[Pictures: Plate 78: Cubomedusae;
Plate 36: Leptomedusae;
Plate 26: Trachomedusae;
Plate 46: Anthomedusae;
Plate 88: Discomedusae;
Plate 16: Narcomedusae, all from Kunstformen der Natur (Art-forms of Nature) by Ernst Haeckel, lithographs by Adolf Giltsch from drawings by Haeckel, 1904 (Images from Wikimedia Commons).]

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