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Nightfall: Can Kalgash Exist? 86

First time accepted submitter jIyajbe (662197) writes Two researchers from the Indian Institute of Astrophysics investigate the imaginary world of Kalgash, a planetary system based on the novel 'Nightfall' (Asimov & Silverberg, 1991). From the arXiv paper: "The system consists of a planet, a moon and an astonishing six suns. The six stars cause the wider universe to be invisible to the inhabitants of the planet. The author explores the consequences of an eclipse and the resulting darkness which the Kalgash people experience for the first time. Our task is to verify if this system is feasible, from the duration of the eclipse, the 'invisibility' of the universe to the complex orbital dynamics." Their conclusion? "We have explored several aspects of Asimov's novel. We have found that the suns, especially Dovim are bright enough to blot out the stars. Kalgash 2 can eclipse Dovim for a period of 9 hours. We also tested one possible star configuration and after running some simulations, we found that the system is possible for short periods of time."
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Nightfall: Can Kalgash Exist?

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  • An excellent book... (Score:5, Interesting)

    by poptix ( 78287 ) on Saturday July 26, 2014 @01:27PM (#47539005) Homepage

    I would recommend this book to anyone, it's an easy read and thought provoking.

    • by dreamchaser ( 49529 ) on Saturday July 26, 2014 @02:31PM (#47539373) Homepage Journal

      Anything by Asimov is recommendable.

      • by hawk ( 1151 )

        I guess you missed the "cash-in, conglomerate it all!" volumes of his lat career. Foundation XXIV, and so forth . . .


        • by Z00L00K ( 682162 )

          I saw those as a wrap-up, not necessarily a cash-in.

          They are still good to read. Especially the unforseen result of the laws of robotics causing alien worlds to be eradicated because the inhabitants weren't human. What if aliens have the same approach? Humans are then seen as beings of lesser value.

          • by hawk ( 1151 )

            >I saw those as a wrap-up, not necessarily a cash-in.

            Perhaps more a monument to his ego, with the bizarre attempt to tie in everything he ever wrote.

            >They are still good to read.

            I forced myself through a couple, and just couldn't do it any more.


            • by Anonymous Coward

              Disagree. The Foundation/Empire/Robot books were much more deftly written than the originals from a literary sense, only because Asimov had forty more years of writing experience under his belt (in Asimov years, which is equal to about 200 years in "normal" writer years). "Foundation's Edge" and "Robots of Dawn" are particularly good; the characterization is much better than that of his early years, IMHO, and the plot twists and complexity are pure classic Asimov. The way Daneel Olivaw evolves into the m

          • Especially the unforseen result of the laws of robotics causing alien worlds to be eradicated because the inhabitants weren't human.

            What book did this? I thought I had read them all.

          • "Humans are then seen as beings of lesser value."


            Nobility is great.. but evolution I think, would require all species to develop to the point that they would place themselves in the most exalted position...

            • Or, more precisely, human descendents who had emigrated to space early had experienced more rapid evolution than those who did so later. Their society's definition of "human" evolved with them to the point that their robots didn't recognize humans from later waves of colonization as human, even though they were subject to the three laws.

              This was in the last R. Daneel Olivaw book, which I believe was "Robots and Empire".

    • I read the short story loooong ago. Is the book similar? Or do they go into more societal concerns? I also saw the movie as well (the 2000 version), and didn't care for it much.

      • by Jason Levine ( 196982 ) on Saturday July 26, 2014 @11:50PM (#47541321) Homepage

        The short story ends as Nightfall is starting. The book extends past into the nightmare of the stars.

        I remember reading the book once and I was completely absorbed in the story. I finally looked up and noticed it was dusk. For a brief moment, I felt panic rising because the stars were going to come out soon. It took a moment to disentangle myself from the story.

        Being able to completely lose yourself in a book can be a good thing most times - other times, it can backfire.

    • by Z00L00K ( 682162 )

      I would say that it is also a study on behavior patterns applicable to humans. When exposed to the unknown panic can occur.

      Nightfall is a typical Science Fiction story that reflects sociology in a fictional setting - which means that the reader will have less prejudice of what's right and what's wrong.

    • I really loved the movie. They made a book out of it? Cool! Gotta look it up! []

  • by Anonymous Coward

    • Configuring the Nightfall system as a Klemperer rosette would be one way of achieving the result - but the symmetry would still be broken by the orbiting moon that gives the eclipse.

      You'd have to have the various stars in more-or-less concentric orbits of different periods. Then, at some point, they'd all get lined up in one (small angle of direction) from which they could all be simultaneously eclipsed. Ah, no, I see my error ; you only need to get them into one half of the sky for the other half to exper

  • I'd be more surprised if researchers had proved his senary sun system could NOT exist. The man was a visionary.

  • Stability (Score:5, Insightful)

    by Livius ( 318358 ) on Saturday July 26, 2014 @01:49PM (#47539153)

    Asimov's story only assumes that the suns' and planets' orbits are in that configuration for a few tens or maybe hundreds of thousands of years, not that they are stable for what astronomers would call the long term.

    • Good point. The multiple suns could be in a temporary pattern that just happens to coexist with that planet's sentient species evolving. Maybe in another hundred thousand the suns will have moved into another pattern that moves some of them further away, and then have "nights" happen more frequently.

    • Re:Stability (Score:4, Interesting)

      by radarskiy ( 2874255 ) on Saturday July 26, 2014 @03:43PM (#47539693)

      The story depends on
      a) the cycle repeating enough times that people cans start to figure out that it is repeating
      b) sufficient conditions for life to evolve in the first place

      So if you do not require that the cycle be permanently stable, then you require two different life-supporting configurations and a transition that can also support life.

      • Space is vast and full of possibility.
      • Re:Stability (Score:4, Interesting)

        by Artifakt ( 700173 ) on Saturday July 26, 2014 @07:32PM (#47540515)

        That's not as challenging as you seem to think. For Nightfall, you could start with the assumption that there's at least one particularly massive star, not so big as a typical A or O that won't stay on the main sequence long enough for life to evolve, but bigger than our G 2 sun, say a G 4 or 5 or even something in the F series. The other five suns can be much lighter, all the way down to red dwarfs in some cases (and the story seems to describe at least one that is). Those small stars don't have nearly the light output of the bigger one - with the right options, The planet can orbit the main star at a distance quite a bit greater than Earth orbits our sun, and be close to the exact optimum of its "Goldylocks" zone or somewhere on the cool side. Then smaller stars could exist in various configurations, and their output is low enough that if they are at, say 5 x what that planet would call an AU, they would essentially just move the planet's climate a bit towards the inner edge of the "goldylocks" range. So long as they don't nudge it completely into the hot zone, why wouldn't life cope? (Note that we are talking about their light ouput raising the planet's temperature, not them gravitationally nudgeing the planet about - gravity and how stable the planet's orbit can be if the orbits of the suns themselves are changing, that's a seperate question) Fictional Kalgash would have to orbit the biggest sun of the group and it would have to count as being near the cooler edge of the life bearing zone before you figure in the other stars, but even before the lesser suns temporarily shift into a quasi-stable configuration that prevents night from occuring except once every several thousand years or whatever, there would be various configurations that would make night a very short lived or rare and irregular thing, and life would be used to that. There are other issues, such as how do plants dispose of waste products on Nightfall world, but those issues don't vary much if there's a short night every few months or only in a thousand years - plants would have to adapt for situations much less prolonged than the current one. If we call the Nightfall orbits "perfect", then even very imperfect multi-star systems would find life constantly facing this problem.I'm thinking that by your argument, it's all too easy to say things such as "Life in Binary systems? Impossible!," and even "Life when the day lasts more than 24 hours 17 minutes? Absurd!", and things like that. I'll refrain from quiting Jeff Goldblum at this point, but hope you will consider this.
                Then there's the question of how sensitive to light the natives eyes are. If nights have always been at least short and irregular for much longer than the perfect situation has existed, we should expect the natives to not have very good night vision, as there's less demand to evolve it, so talking about relative optical wavelength outputs and such is very hard to do meaningfully.I'm not sure how we could criticise the work as SF on that basis.

    • Re:Stability (Score:4, Interesting)

      by dryeo ( 100693 ) on Saturday July 26, 2014 @03:45PM (#47539699)

      Actually the story assumes that Kalgash existed in a stable orbit long enough for technological life to evolve, something that likely takes billions of years with our one example needing a planet that was fairly stable for close to 4.5 billion years.

      • by plover ( 150551 )

        Couldn't an already evolved planet be orbiting a star that is traveling, and is then captured by a multi-star system?

        Assuming that evolution has produced other forms of life in many systems around the universe, it makes sense that it's done so on stars that have then had their travels altered. And yes, there are all kinds of problems. During the transition, would the evolved planet remain a safe distance from the other stars in the cluster? Would any of the life on it survive as it changes to the new orbi

        • by dryeo ( 100693 )

          I'd think that the planets orbit would be perturbed enough that it would no longer be in the Goldilocks zone, or at least the ideal considering its atmosphere (amount of CO2 etc)

      • by Livius ( 318358 )

        It didn't have to be in that orbit the whole time life was evolving, just the time it took the culture to adapt to it and maybe some evolutionary adaptation of their psychology.

        The archaeological evidence of the cyclic fall of civilization only went back a few tens of thousands of years.

        • by dryeo ( 100693 )

          It had to be an orbit that came with a climate that allowed complex life to evolve, about a billion years for Earth. Even the really primitive life would probably need close to ideal conditions to flourish long enough to oxygenate the atmosphere and lay the foundations for complex life.
          Of course with only one sample it's hard to say if there are different routes to complex life.

    • by Anonymous Coward

      Yes. And thank the Heavens for that. I doubt if the authors spent weeks and months on this. This was probably done over a couple of weekends at most. And they probably enjoyed it. It might have even helped them think better about their 'day jobs'. And it shows WHY scientists often get interested in science in the first place. I am an Indian, and I am glad my govt. funded this - even if indirectly. And yes, I know we have a lot of problems that need to be fixed. Just like the rest of the world.

      Now, Get the F

  • by radarskiy ( 2874255 ) on Saturday July 26, 2014 @04:02PM (#47539749)

    "we found that the system is possible for short periods of time"

    They state that their configuration is "stable for a few hundred years", and their graphs only extend to 400 years. The eclipse cycle in the story is 2049 years and has repeated enough times that people are starting to detect that it is fact repeating.

    In reference to tidal forces from the Trey-Patru binary they state "(Though subsequent generations of the Kalgash people will face dangerous scenarios.)".

    Their configuration actually has not been shown to be survivable for even one cycle.

    • by Anonymous Coward

      A good chance life could evolve on a planet like that given the time.

      With more energy comes more opportunity. Life may well evolve to use heavier elements that aren't normally used due to energy constraints.
      We evolved to use the least energy-requiring configurations for the average amount of energy we could consume, which changed over billions of years, and still changes even now from an offspring-to-offspring basis. Hell, it even happens mid-life, you can literally force your body to conserve energy just

  • by rossdee ( 243626 )

    Could such a planet be habitable?

    I'd always thought it would be too hot for (life as we know it, Jim)

  • ... that there is even a debate. Surely all of us sending transmits are not doing so in vain, especially when Saro has responded... twice! We will deliver the baby.

At work, the authority of a person is inversely proportional to the number of pens that person is carrying.