With galaxies ranging in the several trillions, it’s easy to speculate that we’re not the only intelligent species to exist in all of space. The idea of celestial beings living outside of our little planet dominates our movies, news, books, and even music, because we all want to know the truth: Is there life outside of Earth? Or are we loners in this vast, expansive universe?
Here are three reasons for and against life existing outside of Earth.
One in a billion
The conditions under which complex life on Earth was created are almost impossible to replicate. An emerging theory from Germany posits that life on Earth may have started from a meteorite impact – one that had to have been incredibly precise to generate the molecules that now make up our world. Other theories, while differing in the “how,” agree that the merging of cells responsible for Earth’s intelligent beings is extremely rare – most likely a one-time event. Merely having the potential to support life may not be enough; Mars, for example, once had potential to harbor life – yet we still haven’t seen any evidence of this life.
Italian physicist Enrico Fermi raised the following point, known as Fermi’s Paradox, in the ‘50’s: If the universe is indeed billions of years old, and it’s only taken humans a couple hundred thousand years to create technology advanced enough for space travel, then older species in the universe should have been able to colonize the galaxy by now. Human beings are a relatively “young” civilization, and our technology is already sophisticated enough to reach planets hundreds of light years from Earth. Alien civilizations older than ours should have far surpassed us in technological advancement. Yet, as far as we know, no galaxy-domination attempts have been made by the interstellar powers that be – because they probably don’t exist.
The Great Filter
Our lone existence in the universe can be explained by The Great Filter. The theory contends that before a civilization is able to reach the level of intelligence necessary for space colonization, it gets “filtered” by some external circumstance and ceases to exist. On Earth alone, there’s been evidence of at least five mass extinctions, and there are plenty of logical reasons this happens: disease outbreak, climate change, natural disaster – the list goes on. While humans may (or may not) have dodged this inevitable filter, it’s unlikely that our alien counterparts could have done the same. If they did – where are they?
We Share the Universe
The potential is there
Around a billion Earth-like planets are estimated to inhabit our galaxy, making the potential for life extremely high. Even within our own solar system there are several celestial bodies boasting the potential to support life. Jupiter’s icy moon, Europa, for example, contains both a source of radiation strong enough to lead to chemical reactions and evidence of an ocean similar to Earth’s. Similarly, the conditions of Saturn’s moon, Enceladus, could already support an Earth-born microbe (a microscopic organism that is too small to be seen with the naked eye), what with its liquid ocean and hydrothermal reactions. While many speculate that the life we uncover on these moons will likely be microbial, it would be the first step in learning how to search for more complex life forms within our galaxy.
As reported by the New York Times and the Washington Post, the Pentagon quietly allocated $22 million toward the investigation of various unidentified flying objects for a number of years. While much of what they saw is classified, video evidence from a US Navy Jet shows that our skies have indeed been permeated by the unknown. These UFO sightings have ranged from bizarre lights over the New Jersey Turnpike to aircrafts moving faster than sound and hovering around the coast of San Diego. Perhaps a lone UFO could have been explained away by human error, but enough sightings to open a five-year investigation? It seems that someone or something is flying those vehicles – and it’s not us.
We don’t know how to look
We may utilize different ways of communication than our extraterrestrial counterparts, which explains why we haven’t yet made contact with one another – our technologies may not have developed to be compatible with one another. Bacteria and neurons, for example, existed long before we had the means to acknowledge them; it just took a while for us to learn how to see them. Also, while radio signals have been our go-to method for reaching out into interstellar territory, we’ve only had access to this technology for a relatively short amount of time. Radio travels at light-year speed; meaning, if we’ve been sending out signals for 100 years, only planets within 100 light-years of us would have been able to receive said signals. Just because we don’t yet know how to make contact with species outside of our own doesn’t mean they don’t exist.
Bottom line: While there is exciting potential of life-supporting solar bodies in our galaxy, we’re still lacking the evidence – and odds – necessary to prove that life outside of Earth exists. What do you say? Is there a real-life ET out there somewhere for us to discover?