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The normal distribution in which μ is the mean, and σ is the standard deviation. Most of the area under the curve falls in the two-sigma interval between ±2σ. (Via Wikimedia Commons.) |
• Impact by an asteroid or comet.NASA, for example has been taking asteroid tracking very seriously. We should start debating whether we should stop the technological singularity. Taking a plot line from Kurt Vonnegut's novel, "The Sirens of Titan," this singularity might be humanity's purpose. A more optimistic scenario for human existence has just been published on arXiv by scientists from Oxford University (Oxford, UK) and Tufts University (Medford, MA).[5] Instead of just focusing on humans, this study considered the fraction of civilizations in the universe which are long-lived. The "universal doomsday" argument argues that there should be very few since, we, ourselves, are not one of them. The study did a careful analysis of the universal doomsday argument, and the result was that longevity of a civilization is possible if the number of early existential threats is small.[5-6] Longevity is a relative term, since the study predicts just a small fractional chance (a few percent) that we will become a galaxy-colonizing civilization. The key is to devote technology to allay threats such as those listed by Rees, and to actually colonize the galaxy. A distributed population has a better chance for survival of at least some members.
• A particle accelerator might create an Earth-swallowing black hole.
• Global warming.
• Worldwide pandemic, perhaps caused by a virus created by a terrorist organization.
• Artificial intelligence is created, and we reach technological singularity, when humans become irrelavant.
• A gamma ray burst.
• Nuclear holocaust.
• Overpopulation; although there's a feedback mechanism, famine, that limits population.
![]() | The survival probability is graphed as a function of the ratio R = NL/NS, where NL and NS are the populations of long- and short-surviving civilization. The s values correspond to the number of threats (see reference).[5] (Fig. 6 of ref. 5, via ArXiv.) |