I watched this excellent video by Eugene Khutoryansky - https://www.youtube.com/watch?v=GOrWy_yNBvY a while back explaining why life in the universe must end. I don't want to believe this but it seems inevitable since life needs energy and once you fuse matter all the way to Iron, its very hard to get more of that. Lets say there is a master civilization that has made extraordinary strides in technology and can easily perform tasks like creating stars, transporting matter quickly between two points, etc. Is there a plausible scenario where such a civilization could be immortal? Could they have some sort of cycle going that allows them to subsist not for a very long time, but indefinitely?

  • $\begingroup$ this civilization for ever ??? let's hope better for the universe :) $\endgroup$
    – igael
    Dec 20, 2015 at 0:06
  • $\begingroup$ Subsist or exist? $\endgroup$
    – Smoj
    Dec 20, 2015 at 6:31
  • 8
    $\begingroup$ INSUFFICIENT DATA FOR MEANINGFUL ANSWER. $\endgroup$
    – celtschk
    Dec 20, 2015 at 8:12

5 Answers 5


I'm no scientist, but it seems to me that any investigation of how to survive after we've lost our current supply of usable energy, should at least glance at the related question, "where did the energy come from in the first place?".

Your extremely advanced technical society could probably find the answer to that question and apply that answer to creating more energy from where-ever our current supply came from.

  • 3
    $\begingroup$ youtube.com/watch?v=Dc-m9dumEaw - Lisa, in ths house we obey the laws of thermodynamics $\endgroup$ Dec 20, 2015 at 10:38
  • 1
    $\begingroup$ @GaryWalker, +1 for a very funny and appropriate video! But as a layman/non-scientist/neophyte-to-the-worship-of-thermodynamics, let me ask... Where did the energy come from in the first place? What is the established doctrine within the scriptures of science for why we have energy here in the middle of time, when energy is absent both before the big-bang and after the heat death of the universe? "It was created during the big bang" is a great answer... but how was it created?" That is the question I think the OP's advanced society will be able to answer. $\endgroup$ Dec 20, 2015 at 16:46
  • $\begingroup$ @HenryTaylor Energy is conserved. Its only usable energy that's decreasing. $\endgroup$ Dec 20, 2015 at 23:10
  • $\begingroup$ @HenryTaylor - Where did the energy come from? There is no real scientific answer. There may never be. Reversing entropy is simply inconceivable at this time. Where did it all come from: no real scientific answer exists, though there are speculative answers like random vacuum flux, but where did the vacuum flux come from? Maybe a religious answer, God - not exactly something we could choose to reproduce. Some wonder where did God come from, others consider this a same/different type of question than where did the vacuum flux come from? You need something a lot better than WorldBuilding. $\endgroup$ Dec 21, 2015 at 0:14
  • $\begingroup$ @GaryWalker, Which is why I brought it up. To apply some perspective to the OP's question. Rohit is asking if creativity and the application of science can ever defeat entropy, restoring heat loss energy to a usable form. This is a fundamentally unanswerable question because we cannot predict how far science will advance from where we stand today. I'm an optomist at heart, so the other provided answers seemed to fatalistic for me, and given that the OP Question also involves extremely deep time, I think optomism is practically mandatory. $\endgroup$ Dec 21, 2015 at 2:54

The short answer is that all processes will produce heat losses which are unrecoverable. There would be no way to fuel a civilization indefinitely, because only part of the energy input comes back as useful energy output; the rest radiates off into space.


Almost ... maybe ... for a very limited definition of forever.

Frank Tipler wrote a book titled The Physics of Immortality: Modern Cosmology, God and the Resurrection of the Dead.

I read the book when it was first printed. Long book, lots of equations and some pretty wild assumptions.

The basic idea is that computers get fast, AI becomes real, and we simulate all of the possible universes in a computer. Since the computer is so fast, reality inside the simulation passes very quickly, as in trillions times faster than out meat based existence (maybe even faster as the book never gave a limit that I recall). Also, the computer uses less and less energy to the point it can run all of the situations with consuming too much energy.

Tipler then also assumes a big crunch and the energy levels will rise. With the higher energy levels computers compute faster and faster with the higher energy levels kick in, allow more and more simulation.

Tipler also talks abound surviving the big crunch and setting the initial conditions for the next cycle. And oh yeah, we eventually become God, not just any God, but an infinite, omnipotent, omniscient being very similar to the Christian God.

Book is a serious snoozer. Generally physicists were pretty brutal in their reviews. But if you are ok with a simulated civilization, you can approximate infinity.

Of course, others might prefer the Heavenly civilization with the real triune godhead running the show eternally. Not some 2nd rate simulation you know.


If you're talking real civilizations, I'd say there's still a lot of questions whether a civilization can last forever. It's actually a pretty long standing philosophy question, with some colorful commentaries such as Nietzsche's treatment of The Last Man in Thus Said Zarathustra. There, the Last Man was a pocket of civilization which strived for nothing but immortality. Nothing mattered except things which could extend their society forever.

Nietzsche had some strong words to say about that mentality.

Regardless, since this is world building, we can talk about some rather interesting contrived civilizations, and leave it to the physicists to fill in the details. I am aware of at least one interesting approach to lasting forever which is thermodynamically consistent. It doesn't reach up into the stars, however, trying desperately to find more and more energy. Instead, it reaches inward. Thermodynamics requires entropy to always increase in a closed system, but it does not specify how much it has to increase. If you can find a way to create a system which sustains itself using an amount of energy proportional to the remaining energy in the system, then you can continue to progress using exponentially less and less energy. You effectively need to concentrate the usable energy into smaller or more subtle structures as time progresses.

If you're looking at the ability to compute things, Laudauer's principle indicates that the cost of changing a single bit is proportional to temperature, so in theory, if the temperature of the universe were to cool towards absolute zero, you may be able to stretch out your computation forever.

If you try to develop structures which are capable of this, you start to find "self awareness" to be very important. Without it, it is remarkably hard to ration the amount of energy you spend properly. Every fiber of your being needs to act in concert with every other fiber.

A tall task, but hey. Welcome to world building!


Aparently ancient spiritual quantum knowledge says that what is always was. Meaning that if there is life, Life will always be and always was.

The Human mind is a bit limited in its scope and overstanding of existencial concepts based on misconceptions about life and death and therefore finds it perplexing to accept the eternalness of life and energy.

The answer is Yes. But as always we must define "Subsist" to be able to answer the question in detail. :)

  • $\begingroup$ Does this answer the question? $\endgroup$
    – bowlturner
    Feb 2, 2016 at 15:58

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .