The Fermi Paradox asks why our galaxy hasn’t already been colonized by alien civilizations. The argument goes like this. A lot of stars in the Milky Way are like our Sun. Many of them are a lot older than the Sun. Many of these stars would have habitable planets like Earth. If intelligent life developed on some these planets, a few would have developed a technological civilization capable of space travel. Therefore, the galaxy should have already been colonized.
Clearly, however, the galaxy hasn’t been colonized by an alien civilizations. We would have noticed them. For that matter, they would be here by now unless they are deliberately choosing to hide themselves from us. So something must be wrong with the arguments. The often drawn conclusion is that life or at least intelligent life may be very rare. Some go as far to say that we on Earth may be the only intelligent life in our galaxy, perhaps in the universe.
While I believe it is true that many stars in our galaxy will have habitable planets, most of them may not have hospitable to life until much more recently.
The Big Bang occurred 13.796 billion years ago according to latest Planck satellite data. After the Big Bang, the universe went through several phases: a rapid inflation occurring in under a small fraction of a second where the universe expanded to an enormous size, the next 3 minutes that fixed the amount of hydrogen and helium in the universe, cooling with atoms forming 400,000 year later, a dark period until 400 million years, the first stars of hydrogen and helium, the first galaxies 1 billion years after the Big Bang, then 1-9 billion year after the Big Bang galaxies begin to form and eventually evolve into their familiar structures and shapes. Our Milky Way galaxy formed about 1 billion years after the Big Bang. Our solar system formed about 8 billion years later.
The real question for the Fermi Paradox is whether during that first 8 billion years of the Milky Way was it possible for life to have developed and thrived on Earth-like planets in our galaxy. It seems likely life should have arisen during that time unless life is very uncommon in the universe; however, the odds of life getting a hold in our galaxy were probably much reduced in our galaxy’s early history. During the first 8 billion years, our galaxy probably crashed into other galaxies and passed through a period of intense star formation. Recent analysis has shown that the peak of star formation in the universe was between 9 and 11 billion years ago. This would not have been easy period for life to develop or to survive for the extended time required to evolve intelligent life. Many large stars with relatively short lifespans were scattered throughout the galaxy. The death of these stars would result in enormous supernovas that would destroy life on any nearby star system. If life somehow came into being, it could have been destroyed quickly in the next galactic collision or by a gamma ray burst from a nearby exploding star.
One explanation for the Fermi Paradox is simply that the conditions for the first 8-9 billion years in our universe and our galaxy were not conducive to life. Conditions were too chaotic. If we assume that life requires about 4-5 billion years to reach intelligence and consciousness at our level, as was required on Earth, then intelligent life on other planets might be roughly at our level – some more advanced, some less so – but perhaps very few with an ability to colonize the galaxy. Of those with ability to colonize the galaxy, some (maybe even most) may have had little interest in it. At any rate, the extended period of time for any of these civilizations to have colonized the galaxy might not have existed.
Another explanation might be the mysterious dark energy that began accelerating the expansion of the universe. Dark energy is a hypothetical form of energy that cosmologists use to explain the apparent increasing rate of expansion of the universe. Before the observations were made that universe was expanding at an increasing rate, many scientists believed that gravitational pull would eventually cause the matter in the universe to collapse back on itself. Some had cyclic models in which the universe expanded, collapsed, and in a bounce expanded again endlessly.
The nature of dark energy is not in any way understood. It seems to be a force, much like dark matter, which is required to make our observations of the universe work out according to the other laws about which we feel confident. One of the mysteries of dark energy, however, is why did it become more dominant than gravity 5 billion years ago. If dark energy had predominated over gravity in the early universe, galaxies and star systems like ours could not have formed. Life would not exist and we would not be here. This is but another example of the apparent fine-tuning of the universe for life.
Could there be a connection between gravity, dark energy, life, and mind? We know the existence of life requires gravity in the early universe to form stars to create the carbon and other elements for life. Might life also require dark energy to change something fundamental in the nature of matter and space before it could come about?
If that is the case, the fact that our solar system and our Earth with an ability to form life came into existence around 4 billion years ago would not be a coincidence. Life could not have come into existence earlier.
David Layzer has speculated that potential entropy in the universe may be growing at a faster rate than actual entropy. In other words, we should see more disorder in the universe and less structure than we are seeing. The difference between potential and actual entropy allows for the growth of information. Verlinde’s controversial theory of entropic gravity derives gravity as an emergent property from the information associated with material bodies. Gravity and entropy may be connected to information accumulation in the universe. From gravity comes the large-scale structures of the universe. From stars and galaxies come carbon. Life can be thought of as information encoding itself in matter. And mind, of course, is yet another level of information encoding. We might think of all three as accumulation or concentration of information.
This could mean that life and mind are somehow encoded in the universe in the characteristics of space. Five billion years ago, space evolved to enable the development of life. The universe is unfolding in a manner that increases information. Life and mind as we know it may only be transitory states in the evolution of something even greater.