In Vernor Vinge's "Zones of Thought" series, is it possible to detect anomalies related to the zones' boundaries from the Earth using contemporary astrophysics instruments? I.e., if you are violating the fundamental laws of nature (speed of light) there ought to be profound consequences that can be seen from afar.

  • 2
    Well, apparently we can't detect zones with contemporary instruments... So, that would be "no," I guess.
    – DavidW
    Jan 10, 2021 at 21:51
  • Note, IIRC there's a line in one of the books about humanity being surprised when the first explorers found themselves outside the Slow Zone, but I'll have to try to dig it up later.
    – DavidW
    Jan 10, 2021 at 22:00

2 Answers 2


Almost certainly not. At least not with any technology Slow Zone humanity ever discovered.

All humans in the Beyond were descended from a single human colony that accidentally found its way out of the Slow Zone. Said colony had no record of the space-faring Queng Ho and additionally had artifacts from Old Earth (as seen in "The Blabber" short story) so must have descended from a very early human colony. So undoubtedly the Queng Ho came about much later. In fact, Earth has been fully depopulated and resettled at least four times well before the events of deepness in the sky and to repopulate an entire planet multiple times must take thousands of years. Several thousand more years have elapsed between deepness in the sky and fire upon the deep. So we at least have a few thousand years of space-faring humans in the Slow Zone with none of them noticing anything worthwhile to investigate in the Beyond.

Additionally, it was stated that it is completely unknown whether humanity still exists in the Slow Zone at all and that if they do they would be completely ignorant of what happens in the Beyond implying they would have no ability to find out about it, or at least humans on the Beyond don't believe they would develop any ability to find out about it.

The main reason I don't think so is Pham Nuwen himself had access to the best tech humanity has ever produced across hundreds of civilizations in the Slow Zone and spent his entire life searching for any sign of a more advanced society or something unexplained to explore. If there were unexplained observations on the outskirts of the galaxy then he would have been all over it with his expedition.

Note that the speed of light isn't higher in the Beyond, it is just that there is a fundamental limit on the fastest possible computation or density of information that can exist within a volume that is zone dependent. The mechanism that allows FTL travel is extremely computationally intensive, at some point a computer fast enough to perform those computations cannot exist at which point you lose the ability to FTL. But as seen in "The Blabber" and somewhat implied by the On-Off Star, FTL communication at least can happen in the Slow Zone with the expenditure of enormous resources (like the entire output of a star for 200 years, or dimming of a planets sun by a few percent just to send a single bit of information FTL) so whatever fundamental physical laws allow FTL still exist in the Slow Zone, they just cannot be exploited. Both artifacts originated in the Transcend so it is unlikely they could be constructed with Slow Zone or even the Beyond technology.

  • great answer, except - where did it all come from? I've read both A Fire Upon The Deep and A Deepness In The Sky several times each and didn't pick up on the FTL communication from the slow zone or that FTL depended on the computation speed available. Guess I have to find and read The Blabber once more - I only gave that one shot.
    – davidbak
    Jan 26 at 23:08
  • 1
    The blabber has a device that can communicate FTL in the slow zone by dimming the star. It still only can send a few bits. Ravna ponders the fate of bumans still trapped in the slow zone and explicitly says all humans in the beyond are descended from the one colony in fire upon the deep and no one knows if humanity still exists elsewhere. That the zones only affect computation/intelligence is stated a few times and that ftl gets slower due to computational load it stated a few times in fire near the end when they are approaching the tines world. Feb 11 at 23:27

The criterion "related to Zone boundaries" is too vague.

For example, the "On/Off" Star in Deepness was anomalous, and was presumably detectable by anyone pointing a sufficiently sensitive telescope at it. But it was anomalous partly because it was ignoring zone boundaries. So detecting it would not tell you anything about them.

Edit: Why anomalous? It was cycling between dim and bright on a regular 250 year cycle, contrary to any known physics. Any Slow Zone physics, to be more precise. In the larger context of the Zones universe, this was probably because it was engineered or modified by transcendent technology to carry out its function (whatever that was) even in the Slow Zone. So if you already knew about the Zones, and then saw a star located in the Slow Zone behaving like that, you would immediately suspect a violation of the Zone boundaries. But if you did not know about the Zones at all, it would if anything be taken as counter-evidence to a hypothesis that certain physics could happen only in other parts of the galaxy.

  • So, no then? If it was ignoring zones, then the On/Off star means what?
    – DavidW
    Jan 10, 2021 at 21:49
  • Let me reiterate. Possibility or enabling of the ftl travel (imo) must result in some effect seen from afar. Im wrong? Jan 10, 2021 at 22:53
  • Why would FTL travel result in some visible effect? Remember that FTL travel is natural in the fast zone.
    – NomadMaker
    Jan 11, 2021 at 22:48

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