The Role of Fusion in The Future

Not as important as some people think

I received a useful comment on my post from A Flash in The Cosmic Pan from Serban Tanasa asking if nuclear fusion would dramatically alter the calculation I made there. The gist of the post was that the sizes of interstellar civilisations are ultimately limited by the fact exponential growth in energy demand outruns cubic growth in stellar energy availability, and this can help explain the Fermi paradox as well as giving insights into our own far future. Serban believes that being able to add fusion energy to meet this growing demand breaks this relationship and thus undermines the conclusion. As promised in my response, I am now going to lay out in more detail why I don’t think it will do so.

As an aside, this is precisely the sort of interaction I’d like to encourage here. I’m not aiming to make ex cathedra pronouncements to a passive audience - I am testing ideas by seeing what feedback they elicit. As I have mentioned elsewhere, I am writing a book and I would much rather discover…