The similarities between the universe and a living being are surprising and amazing. Can subjects be more alive than we are? Analogies haunt us from early childhood: atoms resemble solar systems, large structures of the Universe are neurons in the human brain, and what is especially interesting is that the number of stars in a galaxy, galaxies in the Universe, atoms in a cell and cells in a living being is approximately equally huge (from 1011 to 1014). Could the universe itself be alive?
What if we are just brain cells of a giant creature that needs to acquire self-awareness? How do we know this? How to check?
Believe it or not, the idea that the sum of everything in the universe is a sentient being has been around for a long time and even became part of the Marvel universe: the character of Eternity.
Eternity Cosplay: Center
It is difficult to answer such a question, since we do not know 100% what consciousness and self-awareness are. But we do know a few physical things that could give us the best possible answer, namely:
- how old is the universe;
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- how long does it take for different objects to exchange signals;
- how big are the largest gravitationally bound structures;
- how many signals must be sent by connected and unrelated structures of various sizes in order to exchange information of any type.
If we do these calculations and then compare them with what happens in the simplest structure like the brain, we can at least approximately answer whether large structures on a cosmic scale in the Universe can be alive.
The universe has existed for 13.8 billion years since the Big Bang and has expanded at a very fast (albeit decreasing) rate since then. It is composed of 68% dark energy, 27% dark matter, 4.9% ordinary matter, 0.1% neutrinos, and about 0.01% photons. This percentage was once different when matter and radiation were more important. Since light always travels at the speed of light - through an expanding universe - we can determine how many "communication sessions" could have taken place between two objects that become connected during this expansion. If we define a "session" as the time it takes to send and receive information one way, this is what we get at 13.8 billion years:
1 communication session: up to 46 billion light years, the entire observable universe
10 communication sessions: up to 2 billion light years, about 0.001% of the Universe: the next 10 million galaxies
100 communications sessions: nearly 300 million light years, nearly the distance to the Coma cluster of about 100,000 galaxies
1000 communication sessions: 44 million light years, almost to the Virgo cluster, which contains about 400 galaxies
100,000 communications: 138,000 light-years across the Milky Way, but that's it
1 billion communications: 14 light-years, within 35 nearby stars and brown dwarfs this number changes as stars move through the galaxy
Our local group is gravitationally bound - it consists of us, Andromeda, the Triangulum galaxy, and possibly 50 other smaller dwarfs - and will eventually merge to form a single bound structure several hundred thousand light years across. Most groups and clusters will meet this fate: since all the associated galaxies in them merge together to form a giant elliptical galaxy several hundred thousand years old, and this structure will last for about 1015 years. After this time, 100,000 times the current age of the Universe, the last stars will burn out their fuel and sink into darkness, leaving only random collisions, flares and ignition, until these objects themselves decay gravitationally in 1017-1022 years.
But these separate large groups will scatter, thanks to dark energy, and therefore will never be able to collide with each other or communicate with each other for a very long time. For example, if we were to send signals today, from our place, at the speed of light, we could only communicate with 3% of the galaxies in our observable universe today; the rest would be forever out of our reach. Therefore, we can only count on small connected groups or clusters, small (containing about a trillion stars, 1012) and larger (like the future Coma cluster) containing about 1015 stars.
Meanwhile, if we need self-awareness, the best example we have would be the human brain, which has roughly 100 billion (1011) neurons and at least 100 trillion (1014) neural connections, and each neuron fires 200 times per second. Considering the average human lifespan of 2-3 billion seconds, many signals are sent during this time. It would take a network of trillions of stars, bounded by a space of a million light years and existing for 1015 years, to get something comparable to the number of neurons, neural connections and the number of transmitted signals in the human brain. However, in general, these numbers - for the brain and for large, fully formed galaxies - are quite comparable.
But the big difference is that neurons within the brain have a coherent, defined structure, while stars within a coherent galaxy or group move rapidly relative to each other, influenced by all other stars and masses within the galaxy.
We believe that this kind of randomization of sources and orientations prevents the formation of a consistent signaling structure of any kind, but this may not be the case. This assumption depends on what we know about the emergence of self-awareness, and, in our opinion, it is simply not enough one sequential back and forth movement between different objects to make it possible. But the total number of signals that can be transmitted on a galactic scale over the lifetime of stars is very interesting and impressive. Still, it's important to note that even if we put it all together, our galaxy will not be very bright - about like a child aged 6 hours. If there is a larger consciousness, it has not yet appeared.
In addition, the concept of "Eternity", which encompasses all the stars and galaxies in the Universe, is probably overkill given the existence of dark energy and what we know about the fate of the Universe. The only way to test this, unfortunately, is to turn to simulations (which have their own drawbacks) or sit and wait by the sea for the weather. Until the consciousness of the Universe tries to contact us, we can only wait.