I found a very interesting commentary by Nick Bostrom, about the existence of extraterrestrial life and the so-called Fermi Paradox.
The point Nick Bostrom presents is sensible: the current evidence is that life is apparently not very frequent in the Universe. Despite all efforts we did toward finding life, intelligent or not, we failed. Moreover, the human progression went from very low technology to space exploration in 10.000 years, a blink of an eye on the Universe time scale. There are pieces of our civilization travelling out there: the Pioneer 10, the two Voyager and much more. In two or three hundreds years, we could be able to manipulate matter so to create self-assembling space probes to scout the galaxy, the Von Neumann probes. If an intelligent civilization exists or existed in the galaxy, we would be surrounded by Von Neumann probes, or at least we would be able to receive some kind of signal, but this does not happen. Apparently, there has to be a filtering event that prevents human-intelligent life to reach a status where galaxy colonization could be started and self maintained without further intervention.
This filtering event could be before our time, or in front of us. If the filtering is before our time, it must act as a showstopper for the development of life forms, meaning that life is rare, potentially unique even on a universe scale.
However, if we happen to find extraterrestrial life, for example on Mars, it would mean that the conditions to form life are rather loose. Life formation is not at all uncommon, and we could expect to find it on any exoplanet with the right conditions, potentially a huge amount in the galaxy. Therefore, to address the experimental evidence of no space colonization despite the billion of years of time passed since the boot-up of the Universe, we are forced to theorize that in this case the filtering event is in front of us: mass extinctions already happened in the past. Could it happen for humanity as well? Under this perspective, Nick Bostrom states that finding no evidence of life on Mars is a good news, as this means that the Great Filter was behind of us, and there’s hope (not certainty) for a bright future, but what if we find something?
Are we the creators of the filter event we have in front of us? Very soon, we will be able to manipulate DNA in its small details, design and create nanomachines from scratch, or fully understand the processes governing our brain and body. Despite the groundbreaking nature of these discoveries, a single accident could wipe out our civilization entirely. It takes a match to start a fire.
Do we need, as Stephen Hawking says, to start colonizing other planetary systems right now, or face the consequences of the “all the eggs in one basket” situation we currently have? Should we accept the fact that our current technology, knowledge of closed biospheres and control of human psychology do not allow us to send a crew on Mars and bring them back? Should we just start sending people there with no chance of coming back? And in any case, once humanity gets there and a colony is started, how can people survive on a planet where water is apparently scarce and there is no breathable air?
