by Sam Andrews
The discussion of the possibility and the implications of the existence of extraterrestrial life are far too often relegated to the realms of science fiction. Specifically, arguments for belief in the existence of life outside of Earth have often been portrayed or treated as ridiculous, unfounded, or just plain nerdy. The first two of these descriptors could not be further from the truth (what can be said for the third, I’m unsure). While it is unlikely that all life outside of Earth is made up of short, green, bug-eyed men flying around in UFOs, or monstrous, jet-black xenomorphs that drool acid and birth out of human stomachs, according to basic probability as well as the findings of modern astrophysics, it is nearly guaranteed that aliens do exist.
In order to understand how probable it is that we are not alone in the universe, one must first comprehend exactly how large the universe is. Seeing as it may very well be impossible for the human mind to fathom the vastness of space, this must be represented mathematically. The observable universe, as far as we have been able to measure, is roughly 8.8x1023 kilometers from “edge” to “edge” (mind you, the observable universe is generally considered to be miniscule compared to the entirety of the universe). In more relative terms, roughly 880,000 Milky Ways, 2.2x1019 Earths, or 4.8x1026 of you could fit in a single file line across the observable universe. Seeing as the universe is a sphere, simple use of the equation V=(4/3)πr3shows that the observable universe could fit 3.57×10x17 Milky Way galaxies, 5.58×1057 Earths, or 5.79×1079 (five quinvigintillion, seven hundred ninety quattuorvigintillion) of you inside it. The point is that the universe is like, pretty big.
After one recognizes this, part of the Drake equation can be used to determine whether or not alien life exists. The Drake equation is: N = R* • fp • ne • fl • fi • fc • L. where N= the number of civilizations that we can potentially contact, R= the formation rate of stars in our galaxy at the current time, fp= the fraction of those stars with planets, ne = the fraction of those planets which develop a suitable environment for life, fl= the fraction of those planets that actually do develop life, fi= the fraction of those species that develop intelligence, fc= those intelligent species which develop interstellar communication, and L= the length of time that these societies exist on average. Of course, we do not know, fl, fi,fc, or L and so we set our own variable: in this case, we can assume one in a million regarding our fractions, and the length of time for which life has existed on Earth for the average length of time which life exists. For our galaxy specifically, according to stats taken from NASA, there are three stars formed in our galaxy yearly, seventeen percent of stars hold planets in orbit, and forty percent of those planets exist within the goldilocks zone. One can then make the following calculations:
This shows that if we consider ourselves to be one in a million (which is relatively self-centered), it is likely that at least 714 planets support alien life, and we can potentially communicate with none of them, currently. However, using our set variable for intelligent life that exists, the value we receive is less than one, when we know that at least one intelligent species exists in the Milky Way (humans), and thus, we can infer that the ratio of either planets that support life to total planets, or life that becomes intelligent to all life forms, is significantly higher (and thus more probable) than we assumed. When these calculations are applied to the total size of the universe, the calculated number of intelligent species with the capability of communication becomes unimaginably high. Essentially, not believing in alien life is a decision contrary to evidence.
As Carl Arthur C. Clarke once said, “Two possibilities exist: we are either alone in the Universe or we are not. Both are equally terrifying.”
While it is extremely probable that unknown life forms exist, there is not a 100% chance. There is always the possibility that we are alone. If we are not alone, then we stand to gain immeasurable quantities of knowledge through communication. If we are alone, then it is our duty to understand, explore, treasure, and love all that this life has to offer us—for if we don’t, no one else will.