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Monday, October 3, 2011

Tiger, tiger, burning steadily

The above is a raw, unprocessed photo from the Cassini flyby of Enceladus on Saturday. No data yet on the actual surface temperatures or energy outputs from the Tiger Stripes, but it is clear from this and other photos from this series that whatever the energy source is, it has not diminished significantly.

Curiouser, and curiouser.


  1. Any pet hypotheses yet which don't involve intelligent extra-terrestrial manufacture? I'm not trying to be funny, I don't have any alternatives myself at this point.

  2. No, I don't. I was thinking about the possibility of a matter/antimatter reaction, but I don't know any way that could be self-sustaining even if some amount of antimatter managed to end up there without leaving a massive crater.

    Volcanism is apparently out of the question (exactly wrong location on the moon, and Mimas has none at all, and if it was it would be a much smaller energy output). So is a naturally occurring atomic reaction like Oklo.

    On the other hand, Enceladus seems a less than ideal landing site for a Bracewell probe.

    Will be giving some thought to this, may post more in a few days when my thoughts are more crystallized.

  3. Also, sixteen gigawatts seems a little excessive for a Bracewell probe. For that matter, sixteen gigawatts is seems excessive for just about anything. That's like the combined energy output of New York, Beijing and London.

    And the location of the Tiger Stripes on the south pole seems unlikely to be an entirely random happenstance.

    I don't know what to make of it either. But it will hopefully inspire congress to get a robot lander onto Enceladus, soon.

  4. Very good point. I've been a little fixated on the fact that it's too much energy output to be any known natural source. I missed the point that it's also too large to be any known artificial source.

    One of my problems with the idea that it's an artificial structure is precisely that an artificial structure the size of the Tiger Stripes, even assuming it were fully operational (whatever that means), should not be shedding enough heat to create what we're seeing.

    Will check in over at the SETA and SETI communities and see if they have any thoughts on the matter. For now, I think any further discussion without further data is necessarily diverging from "speculative astronomy" into "wildly speculative astronomy". That's okay, and I don't mind using this blog as a forum for that. I just want to be clear that this is what we're doing.

  5. "That sounds like something out of science-fiction."

    "We live in a spaceship, dear."

    I knew you were a fan of Firefly and would get the reference.

    Yes, this line of reasoning will probably devolve into science fiction, if it hasn't already. I design spacecraft for a living, you worked on nuclear powered submarines. We both live in somebody elses science fiction. Science blogs like yours must devolve into science fiction occasionally, because the governmental agencies which are collecting the raw data aren't allowed to.

    I have the same thought about the Tiger Stripes being too large (and too energy wasteful) to be an artifact by itself, or by themselves if we think of them as four distinct features. However, as a vent or vents from a much larger object, it starts to make more sense. If Enceladus itself were the artifact, and the Tiger Stripes were the only thermally active portion of that artifact, the energy output starts to seem more reasonable.

  6. Are you still thinking we're looking at something like the Death Star here? That sounded crazy to me back in March. Now, I don't know what is crazy. Or isn't. If the interior of Enceladus were anything other than solid, shouldn't that be apparent from its gravitational influence on Saturn, its rings, and other moons?

  7. I don't think it's likely to be entirely artificial. There has been speculation for decades about boring into an existing asteroid to use as a spacecraft, perhaps this is something like that. I don't know. Planetary science isn't my field. Something is causing a very large heat signature that isn't tidally induced vulcanism or radioactive decay. The heat source is on the south pole of a moon which is smaller than Vesta, but unlike Vesta is startlingly regular in shape and surface composition, with the highest albedo of any object in the solar system.

    I don't think there is an explanation for this which is crazy enough to be dismissed outright, at this point.

    Add to all of this the strong potential for indigenous life and/or reasonable human habitat. I think that Enceladus should certainly be our new priority for exploration, rather than Mars or Europa.

  8. Ockham's Razor, if such can even be applied to this, seems to eliminate any answer other than a very large artificial construction.

    Space Cowgirl is correct, we need to get human explorers onto the surface of Enceladus, and beneath it.

  9. Getting actual human boots on the ground of Enceladus may be beyond what we can realistically achieve at this point. But using robot technology already developed for the exploration of Europa should be feasible.

    As I see it (and will post more about tonight, hopefully) the new information about the Tiger Stripes should shift our space priorities to these three things:

    1) A round-trip human expedition to Mars, to be able to say we've done it. And then forget about Mars. There really isn't much that we can do on Mars that we can't do nearly as well on the moon, more easily.

    2) A permanent and substantial human colony on the moon, beginning with Peary Crater.

    3) A robot probe beneath the surface ice of Enceladus to determine the source of the heat we're seeing.

    These three missions should be attainable in a reasonable amount of time with a reasonable budget.

  10. I see the rationale behind your three priorities, I'm not sure I agree with it.

    Saturn is in fact very far away, especially for the spacecraft currently in production. But for keeping all of our eggs not in one basket, "very far away" is beneficial. Unlike the moon or Mars, a large colony on Enceladus could be self-sustaining immediately without sending multiple provisioning ships. Enceladus has water and energy in abundance, and subsurface temperatures which are at least marginally habitable by humans. It's far enough away from the sun to avoid damage from most solar storms, but receives enough sunlight for photosynthesis.

    Your concept (I believe it's your concept, I've never seen it anywhere else) of landing and spinning a torus on the surface ice is feasible and functional. Building the entire torus in low earth orbit and sending it completed and fully-loaded to Enceladus is utterly realistic. Even if the transit were slow it wouldn't matter, so long as it carried enough water and the ability to produce enough food to get there.

    A colony on our moon is also feasible but would serve a very different function. It would take decades for a lunar colony to be truly self-sufficient. An Enceladan colony would necessarily start out that way.

  11. Interesting thoughts, all.

    And I'm inclined to agree with them. BUT.

    Barack Obama is no John Kennedy. His Republican challengers are no better, and in many cases far worse. And congress presently isn't competent to (perform basic personal hygeine for themselves).

    Unless the energy source on Enceladus turns out to be expolitable and exportable, corporations aren't going to be interested in footing the bill. So at this point, landing a probe there to gather more intel seems like the logical next step to me. And yes, establishing a permanent colony at Peary Crater in the mean time, because imperfect though it may be, we may be able to achieve it this century.

    Yes, I think the idea of landing a spinning torus on Enceladus is my original idea, but it was just a whimsical. Solution to the question of how to create artificial gravity on a moon that small. I have no idea if it would actually work or not, so I don't think it even counts as "science fiction", it's just fiction. But kind of a cool concept, I think.

  12. "Whimsical solution", no period. Perils of Android autocorrect.

  13. Teach them to yearn for the vast and endless sea, Captain. Like Orion, this is too big for governments or corporations. If it's going to be built, it will be built by people like ourselves. Many people like ourselves.

    Please, please write up your concept of the torus, if only to get credit for it. It is at least as plausible as a Dyson Tree, and bears serious consideration.

  14. Again with the Saint-Exupéry. ;)

    Ok, yes, I'll write it up and post it here. But I am a very strong believer that you can accomplish anything at all, if you DON'T care who gets the credit.

    If NASA wants to spark a wide-scale interest in colonizing Enceladus, they need only to say publicly the things that you are saying here.