Heaven’s River – A Quick Description of the Megastructure

*** Spoiler Alert ***

If you haven’t read the book yet, best stop now.

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Heaven’s River – The Topopolis

I’ve seen a few comments that Heaven’s River is not sufficiently well described in the book, so I’ve put together this post to describe it in more detail.

First, let’s start with an O’Neill cylinder, something most people are far more familiar with. Think Babylon 5. An O’Neill cylinder, at its most basic, is just a large drum, rotating around its axis to create centrifugal pseudo-gravity on the inside surface. There are different designs for introducing light into the cylinder, but the one used in Heaven’s River is a fusion-powered light source on a structure that runs down the center of the cylinder.

That’s great, but possibly a little exposed. One good meteor punch and all the air drains out of the cylinder. And like Johanssen said in The Martian, we need air to not die. So stick a non-rotating shell around the cylinder, made of rock or other friable material, to absorb meteor impacts. We make it non-rotating and separate from the cylinder so that it doesn’t place a load on the cylinder. In order to keep the outer shell and the inner cylinder from touching, we place magnetic bearings in the gap.

So far, so good. But with a single cylinder, you can enter and exit through the ends, preferably along the axis where there’s no pseudo-gravity. With a topopolis, not so much. Think of a topopolis as an O’Neill cylinder stretched to a ridiculous length. After all, for any given diameter, a length of ten miles isn’t any more of an engineering challenge that one mile. Or a thousand miles. Or, as in Heaven’s River, a billion miles.

The last thing we do is connect the two ends of the billion-mile-long O’Neill cylinder, so that now you have a loop. In the case of Heaven’s River, instead of going around the star once at a distance of three hundred million miles or so, the structure goes around the star three times at a distance of one hundred million miles or so. There was no engineering reason for that by the way, I just thought it was fun.

But now you have a structure with no convenient ends to enter and exit through. What do you do? Well, the only thing you can do—enter and exit from the side. Of course, that’s easier said than done, because the cylinder is spinning at eighteen hundred miles per hour. And it’s sitting inside a stationary shell. So you have to go through the stationary outer shell, somehow accelerate to a half mile per second while following the curve of the inner shell, then somehow get in through the inner shell. That’s where the Spin Transfer system comes in. You land in one of the nine space ports on the outer shell and get into one of the Spin Transfer system vehicles. The vehicle accelerates along a track on the inside of the stationary outer shell until it matches speed with the inner shell, then the vehicle clamps on to and docks with the inner shell. From there, it’s just an elevator ride to the inner surface of the rotating shell.

Heaven’s River itself has a fifty-six-mile radius, and was built in sections of five hundred and sixty miles each. Think of the sections as individual O’Neil cylinders that got glued together during construction.

Each section has a barrier at each end, which is made to look like mountains, in order to preserve the illusion. The barriers are actually designed to close off the end completely in case of some kind of catastrophic blowout.

The interior of Heaven’s River has four main rivers running through it, each going in alternating directions. But because the Quinlans are semi-aquatic, the rivers were designed to meander, to have tributaries, feeder streams, and so on. This increases the available river and shoreline, which is the ideal Quinlan habitat.

The interior terrain has topography, i.e. hills, valleys, and so on. But there is no reason for the builders to have carted in and dumped a bunch of rocks and dirt to make those hills. In fact, the extra weight would just increase the engineering requirements. So the topography is baked right into the interior shell. You see something similar in Ringworld, where the protagonists are able to see a negative of the ringworld topography when looking at it from the underside.

This design creates empty space under the hills and mountains, which is a perfect place to put infrastructure, including administration and maintenance centers.

A couple of other points…

Like a ringworld, a topopolis cannot have a stable orbit. Technically, it isn’t really even orbiting. So there will be facilities for adjusting the trajectory. I didn’t bring this up in Heaven’s River because it wasn’t relevant to the story, but I would visualize some kind of magnetic levitation system that plays off the star’s magnetic field.

A topopolis ‘bends’. Riker and Bill get into this a bit in the book, but the basic point is that the bend is so slight that no expansion joints are needed and there is really no issue of material fatigue. Most structures in our real lives bend far more than that on a regular basis.

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    • Meghan Chalmers-McDonald on October 8, 2020 at 7:48 pm
    • Reply

    Ok, question. There is a description of it twining like spaghetti, and also in a triple helix. Which I suppose could be a both situation, but spaghetti is not know for its organization. 😉 Now, Googling topopolis gives you two major variations. Loose loops (this seems to fit more with the spaghetti description?) and tight loops (which looks more like a old-timey phone cord). Which were you intending (if either)?

    1. Loose loops. This one is probably the best representation: LINK

      1. There is no picture in your reply Dennis. The only thing I was struggling with was the non-joining of the ends. But now that I understand that it’s spinning like speedo cable in its sleeve I can see why that’s not a problem. It’s such a nuts concept. Brilliant. Only at Chap 17 heh.

    • Roger on October 8, 2020 at 11:23 pm
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    Thanks Dennis, I’m sure that’ll help when I get a crack at the kindle edition. Can’t wait!

    • Scott on October 9, 2020 at 1:24 am
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    Thanks for the explanation, I stopped for a youtube learning session mid book to better picture the topopolis. I love the Bob series, can’t wait to hear what happens in the next adventure.

  1. Thanks for that! Makes it easier to visualize!

    • Bill Ketzeback on October 9, 2020 at 6:26 am
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    I found the book brilliant and really was my favorite of the series. Sure life in a gas giant is fun or the helping of a Stone Age life form ‘evolve and survive’ was interesting but somehow the Quinlan story fascinated me. Picturing alien otters in a preindustrial society was a concept that was believable to me for some reason. Well done, even though this may be the end to the Bobiverse I hope it leads to another book of Bill or other Bobbbbs stumbling into another mess.

    • nadia on October 9, 2020 at 6:43 am
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    if you wanna see a more in-depth check out SFIA video https://www.youtube.com/watch?v=tqs1iQlvV-g shocked you didn’t link it Dennis

    • Eric J on October 9, 2020 at 12:42 pm
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    Yeah yeah yeah. But who changes the lug nuts? Great book!

      • Avinfor on June 26, 2021 at 10:45 am
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      Not sure how the not moving outer layer may work. Think of a spring moving inside a sheath. The spring would exit the sheath, in this case the topopolis should move on the orbital plane and that complicates a lot construction precluding progressive building of segments. Unless the sheath moves as the interior. But that’s not how it is described on the book.

    • Ben on October 9, 2020 at 1:49 pm
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    You are an incredible science fiction author. I’ve read (well, listened to) all of your books and LOVE how you fully develop ideas like this topopolis. You must spend an ungodly amount of time researching and thinking through the consequences of your design decisions. Also, I swear it’s as if you had studied my life and selected all of my favorite topics. Whether it’s talking about ST:TNG, Futurama, D&D, or the prolonged shoutout to Skippy the Magnificent (ExForce is super fun too!), your books always feel like hanging out with good friends. Thank you!

    • Bert Singels on October 9, 2020 at 3:19 pm
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    Thank you for the extra information. I really enjoyed Heavens River (as well as all the other books).
    But it leaves me with a problem. I need more Dennis, there is an insatiable hunger for more now

  2. This made my day to find a bit more detail about the Topopolis. Listening to the book while I drive has resulted in many rewinds as I try to wrap my head around this one. Thanks for sharing this!

    • Jerry on October 11, 2020 at 5:53 pm
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    Hi there! You might consider putting a small spoiler warning at the top of this article – my initial assumption was that this was a description of the book rather than the thing it’s named after.

    I’m really looking forward to reading it!

    • Ken on October 12, 2020 at 2:23 am
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    Hey Dennis! I made a few 3d animations of the topopolis for Isaac Arthurs episode about continent sized space habitats. I put them on YouTube in May. Now they are getting a lot of views thanks to your books! Thanks! My name is Ken York and I am called YD Visual on YouTube.

    • Dimitri on October 12, 2020 at 12:45 pm
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    What a great book! Thank you Mr. Taylor, I enjoyed it very much. I wonder how much you were influenced by the Riverworld Saga by Philip Jose Farmer. The term “scattering” , endless river system, etc?
    Can’t wait for the next book of Bobiverse series…

    • Shawn on October 12, 2020 at 6:03 pm
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    I love it ! I just finished this book and googled your name and found this article. I had some issues with picturing this structure too, but now it makes more sense. I also found myself googling the paper clip problem and learned something else cool. Keep writing more books please! This book among others is keeping my mind off the world burning.

    • Andy on October 14, 2020 at 2:09 pm
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    Thanks, this helps visualize the structure. Quick question, how does it loop around the star? All along one axis or looping to make a star shape, or???

    • Alex on October 14, 2020 at 10:08 pm
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    Why can’t I get the audiobook in IBooks?

    • Dave on October 16, 2020 at 10:47 am
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    I thought it was described pretty well, but since I wasn’t familiar with the terms I did a google search to confirm what I was picturing in my head. This book was awesome and now comes the obligatory demand for you to write faster because I want more. MORE!

    PS thank you

    • Suz on October 25, 2020 at 12:33 pm
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    Awesome! Thanks for this. One more question. Is the topopolis built around the old planet?

    1. No, it’s circling the sun.

  3. You know I just started listening to the audiobook and have a love for these kinds of super structures. Thank you for posting this supplementary material, it really helps fill in some of the questions I had.

    • chuck on November 3, 2020 at 11:57 am
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    Just finished the audio version. Very well written. As a ‘recovering’ programmer (I haven’t written a line of code in anger in about 8 years), I thoroughly enjoy the technical aspects of your writing. Can’t wait for the next one!

    • Aus10 on November 4, 2020 at 3:52 pm
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    Hey dude. I read your book recently. Huge fan of the series. What bothers me is one thing. The closest continuer theory states that if a bob clones himself, then shuts himself down before booting the clone- his “consciousness stream”(soul) will be transferred to the clone (assuming the clone boots first). Then, if the original matrix is booted after, it will acquire a new “soul”, or “consciousness steam”. In bob book one, i may be wrong, but he shuts himself down when his clones are being build after two (Riker) wakes. Logic dictates that since the other clones are all awakened before he wakes in his new ship, the next matrix activated after his sleep would hold the original bobs “soul”. Would that not mean Bill is the continued consciousness of the original bob?

    1. He shut himself down to take a backup, which isn’t really a shutdown so much as a suspension. But he’d be up and running again before restoring the backup into Bill & Co. There was also the transfer of his cube to a version 2 vessel, but that wasn’t until Bill & the others were up and running. So I don’t think there was actually ever an opportunity for soul migration there.

    • Warner on November 7, 2020 at 1:46 pm
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    Dennis I love the whole bob thing! I
    Read book one as a “junk” read on an airport to pass time!! Wow!! Got
    The audio books and loves them all!! Waited years for the next one! And now heavens river. WTF!?? I was very disappointed with it,, you’re much more creative than that! I actually waited years for the next book in the bonaverse series!!d this thing about otters living in a modified Dysom ring is the best you did after book three??!!!. Guess we all have bills to pay. I paid good money for this book,, the next bob verse book,, I’ll wait till it’s free if I even read it. You let
    Me down Dennis. Granted I’m not a published author like you,,,, “But yoh don’t have to be a chef to know the food taste like shit man. You let
    Me down dude.

      • mikevank on November 13, 2020 at 8:33 pm
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      Warner. Books are sometimes written for pure entertainment and others make you sit back and think. I consider the pure entertainment books to be bubblegum books. Lots of flavour and no substance. The books that make you think are written with alot of insight and ideas and are focused on making people consider different ideas and situations. A book like that makes you sit back and go wow. I never thought about that. That is a great idea or different way of thinking of things. Heaven’s river makes you think, amongst other things, about evolution and control. Heaven’s river is not a bubblegum book. Stick with bubblegum books Warner. Be happy. Your comments let us all down.

    • Julian Coccimiglio on November 8, 2020 at 9:25 pm
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    Can you describe how the tram system works on Heaven’s River? I know you said it does something about wrapping around it, But I’m having triple finding it in the audiobook.

    • Steve Vincent on November 9, 2020 at 8:45 am
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    Thank you for posting this description. I listen to you books via Audible, and the one big disadvantage is being able to easily look back a few pages and re-read the a section for clarity. I found that to be the case with Book 4. Love the Bobiverse, and really enjoying going back to it with Heaven’s River. Quite by coincidence I just finished a re-listen to Ringworld and Ringworld Engineers, so finding your take on a similar exploration is fascinating. Like most of the posters above, I was having a really tough time envisioning how the loose spaghetti of the topopolis would work, let alone to extended Oneil’s tubes that make of the core. I’m no engineer, but I think the transitions between each individually rotating segments would be tricky. (Maybe it comes up in the book, but I’m only about a 3rd of the way)

    Anyway… love your books!

    • Jason on November 15, 2020 at 1:02 pm
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    Any news on Earthside?

    • Nana on November 27, 2020 at 4:05 pm
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    What I don’t get is: If it’s twisted, how can it rotate by its axis?

    1. You have to think of astronomical distances. The strand of topopolis bends perhaps one mile for every million miles of length. That’s a .0001% bend. Any bridge or building bends more than that in the wind.

    • Chris on December 2, 2020 at 4:31 pm
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    So when they first enter the Topopolis and accelerate one at a time to catch up with the 1800mph inner shell, taking 4 hours to complete the drone shuttle procedure, how did they all end up at the same point, to enter the inner “elevator”.

    1. Bob goes first stops at elevator.
    2. Drone goes back to pick up Bridget.

    But while all that is happening, is not Bob still moving at 1800mph away from static, initial entry point, now that he’s on the inner shell?

    3. So Does the drone have to accelerate to 3600mph, then 7200mph to catch up to Bob?
    4. And the last run…?

    Thanks, love the books, but this bugged me.

    1. The topopolis takes a bit more than ten minutes to complete a revolution. So if they wait for the same point to launch, they’ll always be following the same flight path. There is, in fact, an optimal flight path that takes into account the drone’s acceleration capability so that they will hit the angular velocity just as they come even with the elevator platform. Please don’t ask me to calculate that!

    • chris on December 2, 2020 at 11:21 pm
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    Ah, I see my mistake, I was placing the O’Neill cylinder as if it rotated within the ENTIRE length, like an inner tube spinning with the tire stationary, but that’s not it.

    It’s rotation is perpendicular to the entire structure like a millions of 2001 wheels connected, sort of.
    So they are only rotating around the 56 miles not the entire length.

    I know its got to be way tougher to write, but maybe sometime explore completely non human, analogue like aliens. Bat like pigs people, otter like, etc vs “The Thing” or you touched on a silicone based life form.

    Be really rare and interesting to interact with something completely non human non biological.

    Seems like our bias assumes life must be biological with alien variations of , essentially us, even though we try to make them “alien”, hair, eyes , blood, sleep, fingers, claws, teeth are still so similar to us.

    Amazing, wonderfully enjoyable books.
    Starting over, reading them to/with my kids.

    Thanks
    Chris
    Boston

      • Jeremy O’Kane on June 19, 2021 at 4:03 am
      • Reply

      There are numerous prerequisites to intelligent life..
      1. It needs to have big brains that can act creatively ad logically. This will mean that life needs to be of a certain size to be intelligent, humans use 30% of there energy to power there brain, that is why they are generally weaker than most primates.
      2. It needs to be able to manipulate materials to create tools. This means having to construct and hone weapons, a rhino or dolphin would have no chance to construct the tools that makes life so useful. The ability to grasp things is useful for climbing, or prying open or pulling things like Dennis’s goriloids. In combat, digits will not increase your probability of survival in any conceivable earth scenario. Assuming carbon based life, which is reasonable as carbon has wonderful binding properties , important in complex information storage chains analogous to DNA. It is likely that evolution is a convergent property in which alien life forms fill roles similar to those on earth such as birds and trees. Considering this, I believe the most likely species to have digits is a primate.

      Other and different species of intelligent life may exist that aren’t medium sized primates, however it is plausible that most intelligent aliens evolved with similar physical traits to humans.

    • Mary Anne on December 3, 2020 at 11:35 am
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    I am lookin for a hard copybook for heavens river. Is it available.

    1. Will be Jan 24th

    • Jim Bell on December 5, 2020 at 6:36 pm
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    Thanks for another great read. Just finished the Audible edition. Very satisfying.
    Jim Bell NSW Australia.

    • Edith DeGolyer on December 20, 2020 at 2:37 pm
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    Really have enjoyed all your books. Can you say anything about the Prometheus Expedition? I can’t find any reference to it in the proceeding three. Have I missed a short story or novella somewhere? Is that a thread for future Bob expansion? I listen to your books often. Thanks again.

    1. The Prometheus Expedition is a setup for a future storyline.

        • Len on December 20, 2020 at 7:27 pm
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        I’m about 1/3 of the way thru Heaven’s River and loving it. Quick question:

        You mention that the structure is a few hundred thousand miles from the sun. But to be a billion miles long in 3 revolutions, it would need to be about 50 million miles from the sun. That would also make more sense in terms of a typical solar system. Am I missing something about understanding the structure of the topopolis?

        1. Where did I mention this? I can’t find it in the text.

            • Shawn Curry on December 27, 2020 at 5:30 pm

            You mentioned it in the description at the top. I saw that and thought you missed a couple zeros (or forgot to divide by two).

          1. Oh, I thought you meant in the book. Thanks.

        • shane stainton on March 25, 2021 at 1:05 am
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        Wait….what?! Prometheus expedition is a setup for anouther book?!!! Oh man….my goodness im so glad to hear you may still write more bob stories. Dennis this series has quickly become one of my all time favorites. You are nose to nose with Tolkien in my “fav series thus far”! Im absolutely captivated by the tales and even if it never does come to fruition know that youve brought some simple pleasures to a jaded old scifi fan 🙂
        I love picking a random spot in any of the stories and sit at my bemch, listening to the bobs while working…it really helps the time fly.
        Again, thank you so much for this wonderful adventure!

    • James Mitchell on January 31, 2021 at 6:47 am
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    I’ve just finished listening to Heaven’s River on Audible – having binged through all the books in the series since I discovered it in October 2020. I hope I won’t have to wait for too long for Book 5.

    I really love the idea of a species living in an artificial rotating object and it reminded me of one of my favourite science fiction books from years ago, Captive Universe by Harry Harrison. I wondered whether you had been inspired at all by this book? It’s a completely different story of course, but the discussions in HR about the Creation and whether the world is an artificial construct make an interesting comparison to those living in Harrison’s Universe.

    1. I don’t remember reading that specific book, although I admit I very well could have. But the idea of the species’ history turning into a mythology isn’t a new one. I vaguely remember a number of generation-ship novels where the occupants reverted to primitivism and developed a mythology about their world.

    • wedge on February 1, 2021 at 12:53 pm
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    OK, I still have an issue with how a hoop can rotate around the inner diameter which is a circle.
    Also, I know you made it big, but surface-wise, it still must be further from the sun at the outer edge than at the inner edge. While this difference is slight it is real.

      • Henry on June 10, 2021 at 9:44 pm
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      I have the same thought and can’t wrap my head around this. No matter the size of the circle, or how slight the bend is, it is not physically possible for a solid ring to rotate along the inner axis (not sure if that is the right term) without deforming. This drove me crazy while reading the book trying to figure out how it would work. I’d be very curious to hear if there is a reasonable explanation that I am just not grasping. Maybe if the individual segments were able to bend independently of each other as they rotated, and that slippage or movement was accommodated for where the segments came together?

      1. A steel bridge flexes far, far, far more every time a car drives across. Skyscrapers flex far, far more due to wind. All structures have to allow for flex. It’s a normal part of the engineering design.

    • Aaron on February 3, 2021 at 8:49 pm
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    Fantastic book, and Ray Porter is a blessing to listen to as always. I actually didn’t find visualising the topopolis all that hard (or inaccurate) from how it was described in the book, as in, I’m not sure I picked up any new revelations from reading this blog post.
    But anyway – I have one lose end to query with you after finishing Heavens River, that is, why did ANEC-23 choose to destroy Bender in the first place when he showed up, instead of engaging in an opening dialogue first?

    1. Not having SCUT, the Quinlan patrol bots operate autonomously. Their job is to clear the system of debris, and that’s what they did. They did transmit a challenge, but Bob (and presumably Bender) didn’t know how to respond.

    • Ray on March 2, 2021 at 5:54 am
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    Thank you for this! I was able to visualize it pretty well in the book but this has been a great additional reference!

    I can’t express how much I’ve enjoyed the whole series, and I think Heaven’s River was a brilliantly creative story and I’m so grateful for the experience. I hope you’ll continue to expand on the Bobiverse, it feels like there are just endless possibilities and plotlines to explore (I know that’s easy to say from the reader’s perspective, and a whole different ballgame for an author)!

    • Andre Southerland on March 5, 2021 at 5:48 am
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    Thanks for that!!!! Makes it a lot easier to visualize the structure….

    • Marr DeBoard on March 9, 2021 at 9:24 pm
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    Maybe I missed it, and this may sound cold, but why were the Bobs so concerned about saving Bender?

    1. Only Bob-1 was really focused on it. The rest were more or less going along with the adventure.

    • Stephen Bridge on April 16, 2021 at 8:21 pm
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    I just finished the audiobook of *Heaven’s River* and as always I am impressed with how Ray Porter seems to be the perfect voice for your style. It’s always a double pleasure when an author and a narrator click, like it is when an author and an illustrator seem to enhance each other’s work. The Bob series has been great, and I enjoyed *The Singularity Trap* just as much. I have heard other writers talk about how happy they are when the right voice is found for their books. I imagine you must be very pleased.

    • Rob on April 30, 2021 at 10:01 pm
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    We started with Outland on audible (I really like Bill and Monica), and moved on to Bobiverse. I play audio books at night and my kid (who is 10) is really picky what books to play, and he adores the Bobiverse. He likes that Rikers name is William (because my kids name is the same), and he likes to pretend he is a Bob and what kind of VR he would create for himself (usually some kind of Indiana Jones temple, filled with treasure), ha.

    • Patrick Shannon on May 12, 2021 at 5:59 pm
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    Wonderful description. I have to say that the Spin Transfer System took me a couple of passes to understand, but once I got it, I could see that it was a well considered solution to a very plausible problem. Someone should make something in Blender.

    On an unrelated note, there was a passing mention of Space Dragons in chapter 6. Considering how portable a replicant matrix is, I hope that wasn’t just a throwaway joke. That concept has a lot of potential to through hilarity and technical challenge into the mix. That, and you KNOW Bridget will want one, at least to use as a Manny.

    • Jenna on August 3, 2021 at 3:15 pm
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    Man… The whole time I was reading I kept thinking I was brilliant for having a “twist” in mind: that Bender had in fact created and built Heaven’s River for the Quinlans, in order to rescue them from a dying planet. (Similar to what the other Bobs had done for Earth, and the Pav). I kept thinking that the destroyed Heaven vessel was a red herring (that it had simply been discarded when Bender upgraded to a newer one), and he’d spent the past hundred or so years making unique advancements in superstructure research, materials construction, and automation, making his tech distinctly unique from the other Bobs’. I fully expected Bender to be the administrator.

    Boy was I glad to be wrong. The idea of an AI tossing the Quinlans back to a pre-industrial age was a far more interesting mystery to unravel. It was a great mechanism to explore the cultural and societal effects of life in a superstructure, rather than just the physical. Though the physical challenges for what was effectively a heist, were also fun to experience!

  1. […] containing a massive habitable volume. (If you want a detailed description, Dennis E Taylor has a post on it on his blog – beware spoilers for Heaven’s River!). The discovery and exploration of the topopolis is […]

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