The fuel that ignites the sun which in turn blesses all living things with
its heat is not infinite.
The nearest star that enjoys the company of a planet that COULD support life is
too far away from our little rock that circles our (by now, only by now) generous Sun.
Therefore the sequence of our descendants could be very long, but finite, unless,
due to our habit of worrying ourselves for the lesser we forget the bigger problems
facing us:
our greed, our stupidity, the delusion that somebody has that
whenever mankind would face a global war there could be a winner,
or a winning nation. Everybody, every nation would lose in such a grim contest.
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Even in the case that 'the world will never stop' it will continue to change and hopefully to evolve, so what are you really worrying about is not clear at all.