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Writing a book. Human numbers and spread after half a billion years. Esitmates.

  1. Dec 30, 2011 #1
    Please forgive me if this fell into the wrong forum. I thought this would be the right place to ask.

    500 million years have past since humanity came in control of a device that could send ships at great speeds across the universe, from the edge of one galaxy to the edge of another in weeks, sometimes even days. (There is a slight randomness of a couple of days to the travel time)

    What I need help with is the numbers, I want them to sound somewhat feasible, now the book is of course a work of fiction and imagination, so an estimate will more than suffice.
    The book I'm writing isn't even anything too serious. I'm just turning, a universe I have been thinking of for several years, into paper.

    In those 500 million years, I have estimated humanity to be in control of five main galaxies, with several other galaxies that are under colonization.

    In the five main galaxies I estimate there is a number of 10 million inhabited star systems, each with a population at an approximate of 10 billion. (There will of course also be smaller systems with populations in the hundreds).

    In the outer galaxies, there are of course less inhabited systems, and less population. Here I'm thinking more in terms of several 100 000 inhabited systems with a population around 1 million to several 100 million in each. (Again, with some systems in the hundreds and some systems with a lot more).

    The main focus on the book will be war. The defense of the galaxies will be in form of large fleet groups.
    One of these fleets will have a couple of 10 thousand ships and more than 1 billion in manpower spread out across that fleet, numbers may vary. Some of the ships are going to be pretty large.
    I'm thinking that each main galaxy garrisons more than 1 thousand of these fleet groups.

    Do my numbers sound alright for a work of fiction, or are they completely unrealistic?
    I would love your opinion on this and any advice you can give. Thank you in advance!

    Bonus question: Should Lucius quit his writing entirely?! :D
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  3. Dec 30, 2011 #2


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    The more realistic number of living humans in half billion years is closer to 0 than to 1 in my opinion.
  4. Dec 30, 2011 #3


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    That was my first thought, but it's pretend. Look at Star Wars, and Star Trek shows, they aren't realistic. So based on his scenarios, what would the numbers be?

    Heck I could do it, but I am on meds.
  5. Dec 31, 2011 #4


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    The average lifetime for a mammal is about two order's of magnitude smaller than your timeline here. Considering the huge leaps of plot you are making you might as well have any number you like though I'm curious as to how you intend to deal with biological, technological and cultural changes over half a billion years. Bear in mind that half a billion years ago was about the time of the Cambrian explosion and from that potentially billions of species have evolved and gone extinct. Also think of the huge technological and social change we have seen in the world in the last century, hell even in the last decade with the growth of the internet. Do you really think you could convincingly write a timeline that is six or seven orders of magnitude greater than that?

    My advice would be to ditch the half a billion figure and go with a few centuries. If you're proposing cheap and quick FTL propulsion then interstellar and intergalactic colonisation becomes much easier (providing you can crack the problem of building habitable, stable environments/terraforming).
  6. Dec 31, 2011 #5
    Don't really need to be a complex calculation. I just want to know if my numbers sound reasonable, or if I'm way off.

    I just have to answer to this. I have seen so many people who seem to doubt that we will make it out into the universe or survive at all, I also had such thoughts, but that's back when I was a teen.
    Why do people generally think we are doomed? Everyone got a personal crystal-ball in their living room that I have completely missed out on?
    I know our society is suffering great turbulence right now, but our society has always suffered great turbulence.

    I bet people in the middle ages also thought we were doomed, now look at us, almost every human in a western society has a better living standard than kings had in the medieval ages.

    You are of course entitled to your own opinion, I must just say that I disagree. I do believe we will make it. We could argue and discuss this until the day we die, both of us can be as much right as we can be wrong. In the end, it's all about faith in the human spirit and in the human ingenuity.
    That's all I had to say. :P
  7. Dec 31, 2011 #6


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    For my perspective see above. Even leaving aside man made or natural disasters standard biological evolution will ensure that Homo sapiens won't survive forever.
  8. Dec 31, 2011 #7
    Good question, and I have thought of this a little. My idea is that policies have been put in place to hinder certain development and genetic advancement. Those policies has then been followed with strict methods, in my book there is even a civil war going on between those who want to keep these policies and those who want to freely go about advancing technology and genetics unhindered.
    That is at least an undetailed idea, my concept is a bit more advanced, but I don't want to go into detail on it. Let's just say that I have thought about it, and have some things in place that might explain the lack of singularity.
  9. Dec 31, 2011 #8
    How can you be so sure? Standard biological evolution might be the thing that ensures we survive forever, or at least for a long while, and if not, don't you think we would have advanced a lot in genetic science to overcome extinction?
  10. Dec 31, 2011 #9


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    Over time species change, we accumulate mutations in our genome that we pass on to the next generation. Natural selection can either remove these mutations, encourage their proliferation or ignore them. Over a very long time i.e. millions of years our species will be completely different because of these changes, if there are groups that have low levels of interbreeding (as their definitely will be with intergalactic colonies) the different changes happening in each group will ensure that they speciate.

    As for your statement on tight political control of technological I don't think it is very likely one policy can be enforced upon millions of worlds for millions of years. At least some of them would just do it anyway (especially if they are founded by a group of colonists who keep their location a secret and act in isolation).

    Forgive me if I sound rude (I in no way mean to be) but do you realise how long a time you are suggesting?? Half a billion years???

    EDIT: Incidentally if you are interested in far (and I mean far) future science fiction you might want to pick up a copy of Alistair Reynolds "House of Suns." It's set 6 million years in the future and the galaxy is populated by millions of species all descended from Humans (either from natural evolution or artificial engineering). The main characters however are classically human because they spend most of their life travelling at close to the speed of light, don't reproduce and don't really partake in any body modification.
    Last edited: Dec 31, 2011
  11. Dec 31, 2011 #10
    True, been looking around a bit, Megafauna species are best documented and seem to last something like about 0.3 -1 million years, looking at mammoths, mastodons and rhinos. The earliest known Homo sapiens is about 200k years. So who is next? Homo Internetiens?
  12. Dec 31, 2011 #11
    I don't understand what you mean. Weeks are made of days. Anything that takes weeks takes days. What's more, the distance between galaxies is not a fixed quantity, some galaxies are relatively close to each other compared to others. I don't understand what you mean by randomness here either. You should write about things you know.
    You do the math.
    Last edited: Dec 31, 2011
  13. Dec 31, 2011 #12


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    Not only that but we are fairly different to those early humans. Hell we only evolved to drink milk beyond infancy ten thousand years ago!
  14. Dec 31, 2011 #13
    Well, there are multicellular animals that survived largely unchanged in the general range of time you're talking about such as the horseshoe crab (Limulus sp.). (It's actually an arachnid, not a crustacean). However, given the likelihood of extensive modification of living systems by intention and combinations of materials that make our present distinction between the biological and non-biological seem quaint, intelligence may be embedded in systems whose characteristics we can't even imagine. Better you should follow the suggestions here and keep things on a human scale: a few centuries at most and Star Trek type characters speaking English and listening to rock n roll. This is not realistic, even on this time scale, but your readers can relate to it. Sexless humans modified to live on airless worlds at 180 Kelvin who grow their young on farms might not be very appealing to readers.
    Last edited: Dec 31, 2011
  15. Dec 31, 2011 #14


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    True but species life time varies between class, insects on average last a lot longer than mammals for example.
    I agree with the augmentation stuff but hard-SF that writes about these settings can be very good. Far more enjoyable than reading about a world where everyone is some idealised version of Now and whose society seems to not be affected at all by the magic technology all around them.
  16. Dec 31, 2011 #15
    Like I said, I have some certain things in place that might explain why humans as we know them now might still be intact after 500 million years.
    But if it doesn't pan out, I could just apply the "Fantasy" tag and not worry at all :)

    Thank you! I am well aware that weeks are made up of days. What I meant was that it sometimes can take two or three weeks to cross and other times it may take just four to six days. The time depending on a certain feature I have imagined.

    And since I doubt we have invented such ways of travel, I doubt anyone actually knows much about it, and even if I'm sure you know all about traveling between galaxies, I'm sure a work of fiction won't be a threat to your reality. (Note the slight irony)

    Please, I just want to know if my numbers sound reasonable for a work of fiction, someone already answered that slightly and I thank you for that. But I would like some more opinions on the numbers.
    I guess that in order to get a straight answer from a human... never mind... what am I thinking?! :P
  17. Dec 31, 2011 #16


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    Considering you are proposing a number of magic plasters to cover your plot holes any number sounds reasonable. Literally any.

    But in the spirit of things let me help you...

    An average of between 1 and 100 billion per solar system (assuming these systems to be similar to our own) sounds reasonable. As we see here now between 1 and 10 billion on a planet is OK, extend that to every Moon and conceive of most available mass turned into O'Neill habitats and between 1-100 for an average system with higher systems even capable of trillions.

    In terms of fleet size it really depends on the technology available. If each ship masses a million tonnes and you are proposing an intergalactic industrial society then even if they just use all the mass of one solar system (similar to ours, disregarding the Sun) they could make 2.8e18 ships. That's 280 million trillion. In light of this your 10,000,000 ship proposal seems very underestimated.
  18. Dec 31, 2011 #17
    I changed "species" to "animal". Afaik, no multicellular animal species has survived for 400-500 My.

    The OP is just starting. It takes a master to pull off what you're talking about.
  19. Dec 31, 2011 #18
    Thank you! This is exactly the kind of answer I was looking for.
    So I think I will increase both ship numbers, size and manpower size for each fleet then, or just increase the fleet numbers.

    Let's say one fleet consists of a couple of moon sized or half-earth sized main ships, with many tens of thousands of smaller ships as support. And five billion or more in manpower spread out across that fleet. Does that sound better?
  20. Dec 31, 2011 #19

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    Actually, Limulus is fairly recent. The genus is 20 million years old. The species limulus polyphemus may be even younger. Yes, there were horseshoe crabs 400 million years ago, but they were not the same as modern ones.

    500 million years is only a little less time that it took to get from starfish-like creatures to humanity. The ballpark number of generations needed for speciation is about 10,000. For people, this is 1/2000 the time you are thinking about.

    Another way to think about it is that humans and chimpanzees split 4 million years ago. You are talking 125 times as much time.
  21. Dec 31, 2011 #20
    You can populate an entire galaxy with 100 billion people?
  22. Dec 31, 2011 #21


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    What mass are you making your ships? My advice for working it out is this; work out the mass for the ships you want, work out how much mass you want your society to budget (back of the envelope calculations tell me that the mass of the Solar system without the sun is ~2.8e27kg) and from that work out the number of ships you like. One tip would be to take the mass of the Moon then decide of how much of the internal volume would be hollowed out for space and use that to work out ship mass.

    Manpower depends on how much automation you want for your ships, they could just be highly sophisticated drones capable of teleoperation or being run by a skeleton crew or (a usual SF trope) just one pilot fused with the ship. When deciding on how many people to put on each ship decide what they are actually going to do.

    Two last points; 1) remember you have to figure out how these Massive ships are going to move, if you're going to throw in artificial gravity, inertial negation etc. 2) Whilst Moon sized ships sound impressive are they worth it? If you took that mass and made a vast fleet of smaller ships you would be able to cover more area at once and would have a much larger ship-surface:ship-volume ratio meaning that a fleet of smaller ships could have vastly more armament than a single Moon sized ship. Indeed all this fleet of smaller ships would need to do is to take advantage of the fact they vastly outgun the large ship and slag its surface so that it cannot fire or be entered etc.
  23. Dec 31, 2011 #22
    There is a problem with the numbers. I don't have time right now to give a full explaination, but it has to do with the make-up of the so-called Local Group. Here is an excerpt from the wiki page:
    wiki - and therefore unreliable
    Perhaps someone else will explain why this makes the numbers in the OP unlikely before I have a chance to come back and do it myself.
  24. Dec 31, 2011 #23
    Thank you, I think I got the basic idea.

    I understand what you are getting at, that one galaxy is not like any other, that they all come in different shapes and sizes. This will be handled in the book. A sidenote might be that this doesn't necessarily need to take place in our local galaxy cluster.
  25. Dec 31, 2011 #24
    Let me make some suggestions which, of course, you are free to ignore. There are some rules for writing good SF. 1)Do not blatantly violate any basic laws of physics as they are currently understood. 2) Develop characters that your (presumably) human readers can relate to.

    Forget FTL travel. It involves some nasty time paradoxes. Instead consider ALS travel (not the disease but Almost Light Speed). You can shorten the ship time to any point in the known universe to be as small as you please, but not zero.

    Energy: Presently cosmologists are considering the possibility of an infinite multiverse. Therefore there is infinite energy from which you can draw at ALS.

    For human characters, let me suggest a tongue in cheek scenario. The earth experiences a catastrophic something (nuclear exchange, epidemic, etc). This attracts the attention of advanced aliens who have been hanging around in the area for some time. They find that some retired baby boomers (BBs) living in Venice, California have somehow survived. Being very ethical beings, they take these BBs under their protection and restore their youth. They also greatly enhance their intelligence so that the BBs can understand and use the alien technology. Being very ethical beings who have not seen social violence for millions of years, they can't imagine that the enhanced BBs would attack them. But they do, and they take over the alien technology (which includes unlimited procreation capabilities) and launch off(at ALS)to bring sex, drugs and rock n roll to the entire universe (but not the entire multiverse).
    Last edited: Dec 31, 2011
  26. Dec 31, 2011 #25


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    If there is only 1-2 planets that can support life in a galaxy, sure, but I thought he said multiple galaxies, which would make more sense.
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