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Imagining Alien Ecospheres

A Europan Scenario

Between living dirigibles on gas giants and potential organisms under the ice, we’ve had quite a week in terms of exotic life-forms. I didn’t have space in yesterday’s review of Unmasking Europa to talk about the book’s chapter on biology, but here’s an interesting glimpse of a not implausible biosphere on that moon, as presented by physicist Richard Greenberg:

Brisk tidal water sweeps over creatures clawed into the ice, bearing a fleet of jellyfish and other floaters to the source of their nourishment. As the water reaches the limits of its flow, it picks oxygen up from the pores of the ice, oxygen formed by the breakdown of frozen H2O and by tiny plants that breath it out as they extract energy from the sun. The floating creatures absorb the ocygen and graze on the plants for a few hours.

The water cools quickly, but before more than a thin layer can freeze, the ebbing tide drags the animals deep down through cracks in the ice to the warmer ocean below. Most of the creatures survive the trip, but some become frozen to the walls of the water channels, and others are grabbed and eaten by anchored creatures waiting for them to drift past. The daily cycle goes on, with plants, herbivores, and carnivores playing out their roles.

Into Jovian Skies

One can only wonder what a rich environment we’ll eventually uncover on this water world. As to Jupiter itself, Larry Klaes’ story on Edwin E. Salpeter and the ‘gasbags of Jupiter’ elicited plenty of interest. Larry passed along this clip from the Cosmos series, containing the relevant comments by Sagan and discussing the development of these ideas:

A world “…in which organic molecules might be falling from the sky like manna from heaven, like the products of the Miller/Urey experiment” is not inconceivable as an abode of life. Sagan and Salpeter’s ‘sinkers,’ ‘floaters’ and ‘hunters’ seize the imagination, but I like the broader frame Sagan places them in: “Biology is more like history than it is like physics. You have to know the past to understand the present. There is no predictive theory of biology just as there is no predictive theory of history. The reason is the same — both subjects are still too complicated for us…”

Understanding how to frame a complex issue is what communication is all about, a fact that’s seldom so gracefully exemplified as in Cosmos.

The Wrong Schaller

If you’ve gone back to look at Larry’s post on Sagan and Salpeter’s Jovians, you’ll have noticed that I changed the artwork. Larry wrote shortly after I posted the story that I had chosen the wrong image — the one from Cosmos, as viewable in the video above, is the one now embedded in the text. As to the other, a Schaller image that I reinsert below, it was used as the cover of the artist’s book Extraterrestrials: A Field Guide for Earthlings (Camden House, 1994). And if memory serves, it also ran as a magazine cover — I suspect on an issue of Analog from the 1970s, but if anyone knows for sure, drop me a note.


Comments on this entry are closed.

  • george scaglione February 28, 2009, 15:27

    not that i have the greatest comments to make on this subject but i do have my own copies of carl sagans cosmos (book and dvd form) and the above sure reminded me of the floaters i saw in both places.maybe somebody could comment because i surly don’t know for sure but could such forms of life become very intelligent? i wonder.imho they could never master spaceflight or much by way of technology because as i just reminded myself – if you live in a gaseous atmosphere…what materials are at your disposal with which to fabricate a spacecraft? but as always i look forward to everyones comments. good to just be a part of such an intelligent group. :) your friend george

  • Adam February 28, 2009, 17:06

    Hi Paul

    It’s not an “Analog” cover like any from the 1970s. Maybe it featured on “Asimov’s” or “F&SF” in the late 1980s. Schaller created some beautifully evocative pieces for “Cosmos” as Larry’s video-trawlling has reminded us. That’s still one of my favourite sections of my battered old copy of the hardcover “Cosmos” from 1980.

  • ljk February 28, 2009, 17:42

    Thank you for adding those wonderful extras for all our benefit
    and enjoyment, Paul.

    As I mentioned in my first article on the Jovian life forms, the
    Sagan and Salpeter paper mentioned that the two Voyager
    probes had cameras powerful enough to detect the floaters
    if they did indeed exist.

    I never heard if anyone then or since did a serious examination
    of the Voyager images of Jupiter’s clouds to look for floaters or
    something like them. Does anyone know if someone did perform
    a search, and would anyone like to undertake an examination of
    those images and the later ones from Galileo and Cassini now?

    Even if these creatures are not found, perhaps some other very
    interesting new details may be discovered in a close examination
    of the Jovian clouds. And maybe Saturn’s too.

  • Administrator February 28, 2009, 18:57

    My Analog collection from that period is intact, but finding something in those stacks is another matter!

    Re Larry’s question, I’ve never heard of anyone searching for Jovian life-forms in the Voyager data (or later Galileo info), but maybe someone will correct me. Fun idea, though.

  • Adam February 28, 2009, 21:39

    Hi Paul

    There was a recent “Analog” cover of a ‘Manta’ like in “A Meeting with Medusa”. Not sure what the story was.

    The best illustration IMHO of Clarke’s own Jovian encounter story was in Robert Shapiro’s classic “Life Off Earth” – the exobiological version of Attenborough’s “Life On Earth”. Had a gorgeous depiction of a beleaguered Medusa with the Mantas attacking in formation. I have that story in “The Sentinel” and while I can’t fault the illustrations – they’re exquisite pencil work – it’s a shame the artist never depicted the Jovians.

    Jovians have always had an appeal for me. As a kid I was entranced by a Frank Paul depiction of four-legged, two-armed Jovians being visited by a man in an armoured vehicle. As a young adult the depiction of Jovians in Clarke’s story and Poul Anderson’s “Three Worlds to Conquer” had equal appeal. Sagan and Schaller’s “Cosmos” seemed heavily indebted to Clarke, while Anderson’s were like Paul’s from the Gernsback era. Of course now both seem rather naive. It’s harder to imagine anything living in Jupiter now – certainly nothing like the gigantic beasts in Bova’s yarns or Moffitt’s “The Jupiter Theft”. Perhaps Juno will produce some surprises and tell us Jupiter has a big core with strange hot oceans?

  • ljk March 1, 2009, 0:48

    Here is a good place to start looking:


  • James M. Essig March 1, 2009, 17:36

    Hi George;

    Those are some very interesting questions.

    My opinion is that if such floaters and sinkers could develop large scale balloon based habitats and eventually develop hard materials such as might support dirigibles, then perhaps they could also fabricate hard materials like graphite fiber and strong polymeric materials. Carbon graphite composite materials so developed might conceivably be fashioned into strong refractory space craft hulls and rockets, or perhaps into mass drivers to launch crewed space craft out of the gravity wells of such gas giant home planets.

    With the development of highly conductive or perhaps superconductive forms of carbon, perhaps the floaters and sinkers could develop novel electrogravatic propulsion systems or other exotic systems requiring very strong magnetic fields and/or super conducting carbonacious materials.

    I look at the example of human beings inside ships within the vacuum of space for instance or humans inside deorbiting space shuttles wherein the outside temperature all around the craft as it re-enters the Earth’s atmosphere is of the same order of magnitude as a blow tourch. Another good example is the travel of humans down to the bottom of the ocean in the Trieste Bathyscaph. Even though these environments would immeadiately kill an uninsulated human body, nonetheless, we have evolved the technology required to travel in these harsh media in mainly only under a century.

    Once a floater or sinker species would reach a critical threshold of techology, their civilization could take off, literally. Atleast that some conjectural muzing on my part.I do not mean to state the obvious but am rather trying to convey my point through arguments by analogy.


    Your Friend Jim

  • Eric March 1, 2009, 18:25

    Looks familiar. On the cover of Omni, possibly?

  • Administrator March 2, 2009, 9:09

    Yes, it’s a maddeningly familiar image. I’m going to take Larry’s tip and search one of the SF cover sites to find it.

  • ljk March 2, 2009, 13:09

    It would be nice if NASA or some other space agency followed
    up on the Galileo mission with an aerobot or balloon probe in
    Jupiter’s atmosphere as a future expedition to that planet. The
    Soviets did it with Venus twice with the Vega 1 and 2 probes
    in 1985, so such a plan is feasible.

    Imagine the views from the imaging systems aboard such a
    balloon probe. This would also give us perhaps our best bet
    to find any floaters or similar life forms among the Jovian
    clouds. Certainly such a mission would inspire the public
    imagination and their willingness to fund such an expedition.

    Here are two online reports on planetary balloon probes:



    Space artist Don Dixon did this evocative work on a future
    balloon mission in Jupiter’s atmosphere:


    And for a bit of fun trivia, 2009 is the 150th anniversary
    of the first stamped mail carried by air aboard a balloon
    named… Jupiter:


  • Administrator March 2, 2009, 14:07

    I’m with you on that, just for the views you mention. Talk about spectacular, and imagine how powerful this could be in terms of galvanizing public interest in the outer planets! The Dixon cloudscape is marvelous.

  • ljk March 2, 2009, 15:09

    Paul, could this be what you were thinking of:


    I also found this artwork by Lynette Cook:


    Here are a whole bunch of floaters and other related
    alien creatures:


    And here are some depictions of Jovians from the days
    when we thought the planet had a solid surface:


  • Administrator March 2, 2009, 15:45

    Larry, nope, it’s not the Asimov’s artwork I’m thinking of, but thanks for the additional links. Lynette’s work is always worth seeing.

  • Adolf Schaller February 24, 2012, 14:41

    Hello Paul and friends,

    I’m Adolf Schaller. Sorry I’m so late to the discussion, but I’m glad i stumbled across it.

    The painting you feature here was specifically composed and painted for the book “Extraterrestrials: A Field Guide for Earthlings” by my long-time collaborator and co-author, amateur astronomer Terence Dickinson and myself. The book was first published in October of 1994, and since I prepared all the illustrations for it that year, none of them existed prior to 1994. To the best of my knowledge, I am not aware that the painting ever appeared in any magazine covers, including science fiction magazines. (If anyone can demonstrate that it has, I should certainly like to know about it!). Perhaps you and your readers harbor the impression of having seen it that way because bookstore proprietors often displayed the book itself much as they do magazines: and the illustration is indeed prominent on the cover. That and other artwork in the book has, however, appeared in some magazine articles and books (mainly aimed at young people) and it is definitely present on the net, such as your site here. (May I ask where you obtained that particular file from? Just curious).

    It pains me slightly that people freely help themselves to use copyrighted material without permission, or consider themselves exempt from paying a nominal usage fee, or not even bothering to credit the artist, but it certainly doesn’t surprise me that it happens, and quite often. It’s more painful to see them distributing horrible-quality image files that they have conjured up somehow out of the ether – or probably just by taking a snapshot from the book. In any case, I’m delighted you and your readers have so enthusiastically resonated with my work over the years. It is most gratifying and almost cancels the pangs I feel whenever I get ripped off.*

    Adolf Schaller

    *The original “Hunters, Floaters and Sinkers”, which measured 90″x120″ was stolen from a storage facility it was kept in by the producers just hours before I arrived to pick it up…that was back in 1981, and its been a constant battle against thieves ever since. I’ve been targeted and stolen from so often I’ve become desensitized to what now seems like routine. The thing that hurts most is that it has eroded away so much of my time and finances over the years that i might have devoted to my work. Many an exciting project has had to be shelved because of the resulting setbacks I’ve been forced to endure. ;(

  • Adolf Schaller February 24, 2012, 15:06

    I’d like to claify a point I made in the footnote. My wording was rather ambiguous. I wish to make it clear that there is no evidence to suggest that the producers or anyone else involved with the Cosmos production were involved in the theft. The perpetrators remain unknown.

    A. Schaller

  • Paul Gilster February 24, 2012, 16:52

    Thank you for your comment, Adolf, and thank you as well for granting permission to publish the beautiful image in the story above (via separate email). Normally I secure permission before publication but obviously didn’t with this image, for reasons that now escape me (mea culpa!). I’m glad you wrote and glad Centauri Dreams can continue to use the image.