In the Dragonriders of Pern series there is an extraterrestrial substance known as Thread. This Thread is nasty stuff that is introduced to the planet of Pern by a rogue planetoid moving close enough to the planet, that Pern's gravity pulls Thread from the rogue planetoid into the atmosphere of Pern, which then falls to the ground and proceeds to eat any carbon based anything it comes into contact with. For more information see the links.

My question is, Is a substance such as Thread theoretically or scientifically possible?

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    I think this belongs more on Biology.SE? Jan 12, 2013 at 12:50
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    Nooo, keep it here! We need really interesting questions like this.
    – user11295
    Jan 12, 2013 at 13:30
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    Dupes are generally not a good idea but two similar specific questions are okay
    – user11295
    Jan 12, 2013 at 14:21
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    Didn't the FAQ, at least in the past, specify that questions about, "Is this stuff from a book or movie really possible?" are inappropriate here?
    – Tango
    Jan 12, 2013 at 17:10
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    There seems to be a gread deal of disagreement wether this belongs here or not. Sorry for making waves.
    – Ender
    Jan 12, 2013 at 21:33

2 Answers 2


The Thread is described as "mycorrhizoid" spores, that " that consumes organic material at a voracious rate, including crops, animals, and any humans in its path".

As such, it sounds somewhat plausible - there are indeed fungi and bacteria which eat all sorts of organics.

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    Self recognition is a bit of a problem for something as voracious as thread. IOW, how does thread know NOT to eat itself? Isolating the recognition factor and figuring out how to produce it in kilogram quantities might prove much cheaper than breeding and keeping dragons. Jan 12, 2013 at 14:05
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    @WayfaringStranger - AFAIK, none of the lifeforms on Earth have this self-recognition problem :) It doesn't sound intractable at all. Jan 13, 2013 at 13:00
  • Also, dragons are way more awesome.
    – SaintWacko
    Jan 15, 2013 at 15:54

It just occurred to me that the Thread could be a genetically engineered weapon designed to destroy life on Pern from some ancient war. After all the whole 200/400 year cycle is a very strange setup.

There's a story, The Plague Star, in the Tuf Voyaging compilation by George RR Martin where Tuf finds an ancient warship that is set to cast plagues upon a planet every hundred years that would make for a similar setup when seen from the point of view of the planet's denizens.

Wether or not it's actually possible in the real world I don't know but in sci-fi in general genetic engineering seems to be accepted as more than capable of creating such a situation.

  • actually it is, and one book mentions this, but my questions is about its real world possibilities.
    – Ender
    Jan 12, 2013 at 15:01
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    As @Ender mentions, the possibility that Thread is a manufactured/genetically engineered organism is mentioned and considered in at least one of the Pern novels, but as far as I can remember, never conclusively determined. Regardless of origin, the ~200 year cycle doesn't require any artificial design, since it's just a factor of celestial mechanics and planetary orbits. The reason for the occasional long interval of ~400 years is also explored in one of the later books. Jan 13, 2013 at 13:39

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