DAMABO, on 06 June 2012 - 06:21 PM, said:
( //Quote shortened // ) ... anyhow, infinite timescale?
Also citing the forum message by DAMABO posted 03 June 2012 (quote shortened): "... given our lifespans may become high enough to not 'need' a replacement, underpopulation does not seem to be an issue."
An infinite timescale makes an estimated event easy enough to calculate. If you with your relatives, partners, fellows, etc., as a society would not 'need' replacements, then it looks like you are betting on lifespans that would be long enough to choose rejuvenation over children. Since it does not look too problematic to get a clue about a time when ancestors of procreative humans have arisen, but very hard to calculate the probability for the end of an evolution in which their descendants would be gone, it can be practical to choose an infinite time. That is not so different from what can be tried with the concept of immortality. When life in your society is about to go on for a long time without births and deaths, your society might eventually be called immortals.
Citing from the article about the project Mars One referred through by the URL (digitaltrends.com/cool-tech/mars-one-plans-human-colonization-of-mars-by-april-2023/) in the above posting: "let us know in the comments below if you’d be willing to leave the comforts of Earth to spend the rest of your life..." Since your society want their lifespans getting higher, they may not want the rest of their life being finished before a time when some very improved rejuvenation therapy could become available by any means of plausible estimations. Do you even want to calculate a fixed period of time for the rest of your life or leave it an open question? If it remains an open question, would we even know when a project of settlement on Mars has been successfully accomplished? Only realize, the success of the project has been described as, citation: " Private corporations like ... are racing to become the next household name that children will be talking about for generations..." Generations means new birth rates and not higher lifespans, that makes things more complicated.
As an example about an infinite timescale: http://ec.europa.eu/...ications_en.htm
is linking to the document "Guidance on the calculation, presentation and use of collective doses for routine discharges." It cites: "UNSCEAR (2000). Sources and effects of ionizing radiation". Volume 1: Sources. UN, New York (2000). According to the EU publication, estimates published in that volume needed an infinite timescale. For the European Commission, this source alone has not been sufficient for further studies. Considering it comes from the UN, would it not look very scientific for the public, at least within one decade or so?