by Timur Ibragimov and Alexander Cernei
“We, this people, on a small and lonely planet
Traveling through casual space
Past aloof stars, across the way of indifferent suns
To a destination where all signs tell us
It is possible and imperative that we learn
A brave and startling truth.”
– Maya Angelou, A Brave and Startling Truth
How did the Earth become the way it is today? Surely it did not spontaneously appear. Like for all planets and moons, the answer lies in gravity and tremendous amounts of time. Four and a half billion years ago, a cloud of gas and dust coalesced to form our planet Earth (“History of,” 2014). After hundreds of millions of years, something remarkable developed in the depths of the ocean — living organisms (2014). These organisms developed into the two separate domains: bacteria and archaea, evolving into separate varieties of prokaryotic (cells lacking nucleus) organisms (2014). Around 2.1 billion years ago, eukaryotic (cells with a nucleus) organisms developed, and after 3 billion years of simple organisms, multicellular, complex life began to emerge (“History of,” 2014; Bennett, Donahue, Schneider, & Voit, 2013). 200 million years ago, the first mammals appeared, and only 40,000 years ago did the first intelligent organism evolve, known as Homo sapien sapiens – the modern human (Bennett, Donahue, Schneider, & Voit, 2013; Bryant, 2002). The existence of humans on the cosmic scale is thus only a speck of over 3 billion years of evolution!
Have you ever considered the size of the United States from coast to coast? How about the size of planet Earth around the equator (roughly from California to the Philippines)? What about the distance from Earth to the Moon? To Mars? To Jupiter? Have you ever looked up at the night sky, and pondered the number of stars beyond our scopes, beyond our myopic vision, beyond the Solar System, in the entire observable universe? And how about the planets and moons and the sizes of those bodies around these stars? In truth, our observable universe contains roughly as many stars as there are grains of sand on every beach of every shore of each coast around the world (Bennett, Donahue, Schneider, & Voit, 2013). But how can we not question whether our planet was the only planet in the universe to undergo these fortunate series of events that gave rise to life?
Fortunately, a group of scientists formed an organization known as SETI, or the Search for Extraterrestrial Intelligence, that delves deep into the universe’s mysteries in an attempt to solve this question (Pierson, n.d.). SETI was founded by cosmologist Carl Sagan and astrophysicist Frank Drake on November 20th, 1984, as a non-profit research organization (n.d.). Although Carl Sagan passed away decades ago, both scientists are widely known for their efforts in searching for extraterrestrial life and attempting to figure out the origins of life in the universe (n.d.). SETI looks for alien life using the radio interferometer called the Allen Telescope Array (ATA), a collection of radio telescopes working in tandem to produce a single image (Pierson, n.d.; “Radio,” n.d.). The ATA scans the sky for signals with frequencies between 1 GHz and 10 GHz (which astronomers believe are most optimal for radio-signal communication between civilizations) that is then processed and analyzed for patterns that could indicate the presence of intelligent life (“SETI,” n.d.).
SETI has made several attempts to contact extraterrestrial life in the last century. One prominent example occurred in 1974, when SETI received a grant to use the Puerto Rican Arecibo Radio Telescope, the largest radio telescope in the world (see Figure 1), to send a simple, pictorial signal, consisting of 1679 bits, to Messier 13, a globular cluster roughly 21,000 light years away from the Earth in the Milky Way (see Figures 2 and 3) (“Arecibo,” n.d.). One likely reason M13 was selected as a target was due to its significant age (over 11 billion years old), extreme density, and number of stars, making it a possible candidate for harboring old, advanced intergalactic civilizations (Plotner, 2016). The broadcast of Arecibo radio signal lasted only a few minutes, but this signal, in principle, can be detected by any radio telescope similar in size to the Arecibo (“Arecibo,” n.d.). Their message aimed to disperse detailed information about the presence and description of humans in, what they perceived as, a universally understandable form (n.d.).
Although these decisions by SETI are promising to space exploration, they face much criticism. For instance, theoretical physicist and cosmologist Stephen Hawking warned at a conference: “A civilization reading one of our messages could be billions of years ahead of us. If so, they will be vastly more powerful, and may not see us as any more valuable than we see bacteria” (Although we know how important bacteria are to us, Mr. Hawking!) (Cofield, 2015). This standpoint is not uncommon, as the Hollywood movies have done a great deal in creating a sinister portrayal of extraterrestrials, ever since works such as H.G. Wells’ War of the Worlds and Tim Burton’s Mars Attacks! Indeed, SETI often takes actions which represent and may affect all of humanity (including DNA and height) (see Figure 2), without the consent of all of humanity. Our convictions and preconceived visualizations of extraterrestrials are primarily what propel and inhibit our search for aliens.
In conjunction with founding SETI, Frank Drake also formulated an equation in 1961 designed to determine the number of possible civilizations in the Milky Way galaxy (see Figure 4) (“The Drake,” n.d.). The formula is meant to consider several germane factors to rule out the theoretical amount of intelligent civilizations.
Drake’s equation is a probabilistic approach of weighing in significant factors to guess the amount of civilizations in our galaxy. This formula does not have any definite solution, as the concepts involved are hypothetical in terms of value and validity (“The Drake,” n.d.). Though this formula does not encompass all aspects of extraterrestrial life, it is, by far, the most promising one. Try it out on your own, and see what your estimate for civilizations in the Milky Way is (see Figure 4 for equation):
N – number of civilizations in the Milky Way
R* –The rate of formation of stars in the Milky Way
Fp – the fraction of R* that have planets and moons
Ne – the number of planets per star which are suitable for life
fl – the fraction of Ne where life does emerge
fi – the fraction of fl that may have intelligent life
fc – the fraction of fi that can communicate via signals
L – the duration of existence of these communicating civilizations (n.d.).
A question that SETI often struggles with happens to be a famous paradox proposed by Enrico Fermi in 1950 (“Fermi,” n.d.). The problem states that if intelligent life could exist, and at least one of those civilizations developed the technology needed for space travel, then they should be able to explore the entirety of the Milky Way and conquer it (n.d.). If the process was so simple, why have we not found them? Perhaps they, whatever they are, are still exploring and have not yet encountered us? Perhaps they already know we are here and we are being monitored as we speak from distant Solar System bodies? Or perhaps they already have encountered us, and live amongst us, somewhere in the enormous planet Earth. Many scientists, however, proposed their own hypotheses for this paradox. Some say that the technology for interstellar travel is either too expensive or not feasible, or even that humanity is the most advanced life form in the galaxy and there are no more developed civilizations (n.d.). We may even be alone, pitted face to face against a colossal galaxy of isolation.