The universe is an even bigger waste of space than we had imagined. Some scholars at Oxford reconsider the famous Drake Equation — an attempt at estimating the number of intelligent civilizations in our galaxy — and find that the number of civilizations in the Milky Way is likely no more than one (emphasis mine):
When we take account of realistic uncertainty, replacing point estimates by probability distributions that reflect current scientific understanding, we find no reason to be highly confident that the galaxy (or observable universe) contains other civilizations, and thus no longer find our observations in conflict with our prior probabilities. We found qualitatively similar results through two different methods: using the authors’ assessments of current scientific knowledge bearing on key parameters, and using the divergent estimates of these parameters in the astrobiology literature as a proxy for current scientific uncertainty.
When we update this prior in light of the Fermi observation, we find a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable.
Thus, the study suggests that we shouldn’t be terribly surprised if we fail to detect any signs of intelligent life in the universe. In a sense, this is reassuring. If the Drake Equation amply explains the cosmic silence, then we can worry a bit less about the hypothesis of a universal Exterminator that wipes out all life forms that get too smart for their own good.
On the other hand, the strong possibility that we are literally alone in the observable universe makes it all the more necessary for humanity to start pushing out into other neighborhoods. So says Musk:
· 25 Jun
This is why we must preserve the light of consciousness by becoming a spacefaring civilization & extending life to other planets https://twitter.com/worldandscience/status/1011081640158945280 …
It is unknown whether we are the only civilization currently alive in the observable universe, but any chance that we are is added impetus for extending life beyond Earth
10:15 AM – Jun 25, 2018
The USG will likely be too preoccupied with its own problems over the rest of the century to even think about interplanetary colonization. Can the private sector handle it? Or will the US pass the torch of space exploration to its global competitors?