Unimaginable vastness and size; that is our Universe. Its ever-expanding nature is filled with a nearly infinite supply of potential life-giving planets and moons leaves us with one question: Are we alone in the Universe?
Considering the size of the Universe, life could be abundant and humanity being the only intelligent life form is highly unlikely. Recently the Mars rover Curiosity discovered organic molecules in rocks on the red planet. This doesn’t necessarily mean there is life there, past or present, but it does indicate that some of the building blocks that created life on Earth are present.
The Drake Equation, proposed by astronomer Dr. Frank Drake in the 1960s, is used to figure out the number of civilizations in the Milky Way that seek to communicate with each other and estimate the probability of intelligent life. The equation is highly speculative as it uses hypotheses to try and calculate the number of civilizations:
The Drake Equation: N = R* x fp x ne x fl x fi x fc x L
N = The number of civilizations in the Milky Way Galaxy whose electromagnetic emissions are detectable.
R* = The rate of formation of stars suitable for the development of intelligent life.
fp = The fraction of those stars with planetary systems.
nhz = The number of planets, per solar system, with an environment suitable for life.
fl = The fraction of suitable planets on which life actually appears.
fi = The fraction of life bearing planets on which intelligent life emerges.
fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L = The length of time such civilizations release detectable signals into space.
Scientists cannot give a precise number on any of these, because we simply don’t know yet. At some point in the future we might, but at the moment we can rely on educated guesses using the data that we already have.
No matter if the lowest possible chance for advanced alien civilizations becomes true, providing it isn’t zero, there should be plenty of life in the vast Universe.
A November 2013 study using data from the Kepler Space Telescope suggested that one in five sun-like stars has an Earth-size planet orbiting in the habitable region of its star.
Astronomers estimated that there are about 100 thousand million stars in the Milky Way alone, with an estimate of 10 percent having planetary systems. With data from the Hubble Telescope, scientists have found that the observable Universe contains 10 times more galaxies than originally thought — the new estimation is that there are 2 trillion galaxies in the observable Universe.
This means that there could be trillions of habitable planets that could have life and millions that should have evolved intelligent life. With such a staggering number of possibilities, why have we not been visited by E.T.?
The Fermi Paradox
The Fermi Paradox is the apparent contradiction between the high probability of the existence of extraterrestrial civilizations and the lack of contact with such civilizations. It tries to answer the question of where are all the aliens and why we haven’t heard from them.
Thetheory states that we should have been visited by little green men already because the solar system and Earth are a fairly young compared to the age of the Universe and interstellar travel might be easy to achieve. The Universe is estimated to be 13.8 billion years old and the solar system is about4.6 billion years old. It is believed that modern humans evolved 200 thousand years ago and the earliest signs of civilization as we know it come from six thousand years ago.
Michael H. Hart wrote an explanation of the Fermi Paradox in the Royal Astronomical Society (RAS) Quarterly Journal in 1975.
“We observe that no intelligent beings from outer space are now present on Earth,” Hart wrote. “It is suggested that this fact can best be explained by the hypothesis that there are no other advanced civilizations in our galaxy.”
While Hart believes that humanity was the only advanced civilization in the galaxy — his argument was that in Earth’s history, somebody could have visited us already, unless they started their journey less than two million years ago — he outlined four arguments exploring the paradox.
The first is that aliens have never visited us because of a physical difficulty “that makes space travel infeasible,” which could be related to astronomy, biology or engineering. The second is that an advanced civilization decided never to come to Earth. Maybe they were disappointed that we are using the internet for memes?
It could also be that aliens have become advanced enough too recently to be able to reach us — the closest star system to our own is Proxima Centauri, which is about 270,000 Astronomical Units, or 4.25 light years away. For example,spacecraft Voyager 1, launched in 1977 and, travelling at 11 miles per second, is now 137 AU from the Sun. The last argument proposed by Hart is that aliens have visited the third planet from the sun in the past, but we have not observed them.
There is a perplexing scientific anomaly. Despite there being billions of stars in our home Milky Way galaxy we are yet to encounter any signs of an advanced alien civilization. Why is that?
This is a question that generations of scientists and philosophers have tackled since the Fermi Paradox first appeared decades ago. Some have suggested that something is preventing alien evolution to take place, others believe that life outside of our blue planet might be hibernating. It could also be like Hart states that aliens just choose not to associate with us.
First in, Last out
A new study by theoretical physicist Alexander Berezin from the National Research University of Electronic Technology in Russia proposes a new explanation. He calls this the “First in, last out” solution to the Fermi Paradox.
Berezin’s paper hasn’t been yet reviewed by other scientists, but it proposes a “trivial solution, requiring no controversial assumptions” that could prove “hard to accept, as it predicts a future for our own civilization that is even worse than extinction.”
Berezin writes, the problem with some of the solutions to the Fermi Paradox is that they define alien life too narrowly. Berezin writes that “the specific nature of civilizations arising to interstellar level should no matter. They might [be] biological organisms like ourselves, rogue AIs that rebelled against their creators, or distributed planet-scale minds like those described by Stanislaw Lem in Solaris.”
Even with such a wide definition we are still not seeing any evidence of these things in the Universe. For the purposes of solving the paradox, Berezin says the only parameter to define extraterrestrial life is the physical threshold at which we can observe its existence.
Berezin’s proposal is quite a grim scenario.
“What if the first life that reaches interstellar travel capability necessarily eradicates all competition to fuel its own expansion?” he hypotheses.
This doesn’t necessarily mean an advanced alien race would consciously wipe out other life forms, but “they simply won’t notice, the same way a construction crew demolishes an anthill to build real estate because they lack incentive to protect it.”
According to Berezin, we aren’t the ones that will have our civilization demolished by ignorant aliens. He believes that we are the future destroyers of the much sought after extraterrestrial life.
“We are the first to arrive at the [interstellar] stage. And, most likely, will be the last to leave,” Berezin writes.
Such an outcome won’t be designed or planned by us. It will be the outcome of a completely unrestricted system that is too vast for any individual to control.
Berezin gives the examples of free-market capitalism and the dangers of an artificial intelligence (AI) unrestrained on its accumulation of power.
“One rogue AI can potentially populate the entire supercluster with copies of itself, turning every solar system into a supercomputer, and there is no use asking why it would do that,” the paper states.
This is quite a terrifying look at the Fermi Paradox. We might be the winners of a survival race that we didn’t even know we were in.
“We are the paradox resolution made manifest,” writes Andrew Masterson, the news editor of Cosmos.
Even Berezin hopes he isn’t right about this.
Dissolving the Fermi Paradox
Another recent study, conducted by scholars from the Future of Humanity Institute at Oxford University, reevaluates the Fermi Paradox in such a way that makes it seem that humanity may be alone in the observable Universe.
The study is titled “Dissolving the Fermi Paradox” and was conducted by Anders Sandberg, a Research Fellow at the Future of Humanity Institute and a Martin Senior Fellow at Oxford University, Eric Drexler, an engineer who popularized the concept of nanotechnology and Toby Ord, an Australian moral philosopher at Oxford University.
They took a fresh look at the Drake Equation that is based on hypothetical values for multiple factors and has been traditionally used to show that even if the amount of life developing at any given place is small, the sheer size of possible sites in our Universe should yield a large number of observable civilizations.
As previously stated, the Drake Equation is highly speculative and it might be one of the reasons why the Fermi Paradox cannot be given a universally acceptable answer.
Sandberg, Drexler, and Ord reconsidered the parameters of the famous equation by incorporating models of chemical and genetic transitions on paths to the origin of life. From this, they showed that there is a large amount of scientific uncertainties that span multiple orders of magnitude.
The paper looked at the equation’s parameters as uncertainty ranges. The authors didn’t focus on what value they might have but instead looked at the largest and smallest possible values they could have based on existing knowledge.
Although some values have a very good estimation (number of planets in the Milky Way based on exoplanet studies and the number that exists within the habitable zone) others are far from certain. For example, it is impossible to have accurate estimations on the fraction of suitable planets on which life actually appears or the fraction of life-bearing planets on which intelligent life emerges. The team got a distribution by combining these uncertainties.
Because of the number of uncertainties involved, there is a broad spread. As the paper explains this, it provided them with an estimate of the likelihood that we are alone in the galaxy. Although the conclusions of Sandberg, Drexler, and Ord doesn’t mean that humans are alone, or that the probability of finding advanced civilizations is low, it provides us with a greater confidence that we are more likely than not alone in the Milky Way Galaxy at the moment with our current knowledge.
In the end, “Dissolving the Fermi Paradox” indicates that we still have much to learn before we can even attempt to determine how many technologically advanced civilizations are out there.
Although recent studies leave us gazing up at the stars wondering if we are destined to be alone in time and space, there is still much we don’t know.