Are There Aliens? Evidence, Theories and Scientific Search

Like many things on this planet, the inquiry into the existence of extraterrestrials has caused much debate and controversy through the course of history. Most cultures around the globe created their own underlying theories and even myths suggesting humans are not the only living beings on Earth. From ancient civilizations till scientific studies of the 21st century, people have always wondered and theorized the existence of life outside our planet. It’s safe to say that we still haven’t discovered undeniable proof of alien life, and we probably won’t anytime soon. But after considering our planet, the universe, and everything that is in it, we can make some educated conclusions. This article explores the possibility of alien life from historical, scientific, and philosophical perspectives.

The existence of over 200 billion galaxies that human beings still need to explore is one of the strongest arguments made by scientists regarding the existence of extraterrestrial beings. Using current technology estimates suggest that the observable universe is 93 million light-years wide. Within our own Milky Way galaxy there are close to about 400 billion stars, and each one of those has numerous planets rotating around it. It is quite presumable and has been non-eticulously proven that the likelihood of Earth being the only planet to beinhabitant is almost impossible.

In 1961, an American astrophysicist, Frank Drake, developed an equation to estimate how many civilizations in our galaxy might be capable of communication. The equation takes into consideration aspects such as:

– stars being produced in a year
– fraction of stars that have planets
– number of planets that may be habitable per star
– chances of life evolving
– fraction of civilizations that reach an advanced technological level

Even though there are no precise set values for these variables, a significant number of scientists argue that there is bound to be intelligent life somewhere in the Milky Way.

Microbial Life

The simplest, most probable, and least complex from of extraterrestrial life is microbial. If there is life on other planets, they are possibly similar to the archaea or bacteria that thrive in the extreme environments on Earth.

Intelligent Life

If higher forms of alien life exist, then it is plausible that they could have developed more advanced technologies for interstellar travel, communication, or perhaps even altering the course of human history as some conspiracy theory suggest.

Post biological and Artificial Life

There is speculation by some scientists that it is possible for advanced alien civilizations to have transitioned into life forms that are artificially intelligent and machine based, thus surpassing biological limitations.

Exoplanets in The Habitable Zone

To date, astronomers have located thousands of exoplanets within other solar systems. A proportion of them is within the boundaries of liquid water and viable life referred to as “the habitable zone.”

Proxima b

This exoplanet is located within the habitable zone of its host star, Proxima Centauri, the exoplanet’s closest neighbouring star to our solar system, making it, potentially, reachable for human habitability.

TRAPPIST-1 System

With at least seven earth-like planets revolving around it in the habitable zone, the TRAPPIST -1 system is, rather, a potential candidate for alien life.

Moons in Our Solar Syste

A few moons in our Solar System suggest evidence of having microbial life.

• Europa: A moon of Jupiter, Europa has a subsurface ocean, which lies below the icy crust, suggesting the possibility of life.
• Enceladus: A moon of Saturn, Enceladus has geysers erupting water vapour, indicating the existence of a warm ocean beneath the surface.
• Titan: Another moon of Saturn, Titan, contains large methane lakes, possibly hinting at life, though existing in a different form.

Evidence for Alien Life

Extremophile on Earth

Life on Earth exists in extreme conditions, such as deep sea vents, acidic lakes, and radioactive regions. This indicates the possibility of extraterrestrial life existing in zones previously regarded uninhabitable.

The Wow! Signal

In 1977, a strong radio signal from faraway space was received. This signal, which remains unexplained, is known as the Wow! Signal. It still hasn’t been replicated.

Oumuamua – A New Asteroid

In 2017, astronomers found a new cigar shaped asteroid in the Solar System, which they named Oumuamua. While most agree that it is an asteroid, some scientists, like Avi Loeb from Harvard, believe it might be an extraterrestrial probe.

UFO Sightings and Reports from Governments

Governments around the world including the US Pentagon have received numerous reports of unidentified floating objects that defy known aviation capabilities. Some reports attest that these phenomena have capabilities that are so advanced it could only be believed to be manufactured by extraterrestrial beings.

The Fermi Problem – Where Are They?

One of the biggest questions the Fermi Paradox raises is, if the universe has so many forms of life, why have we not detected aliens?

Possible Solutions

• Aliens Are Too Far Away – Traveling and communicating between stars is beyond the scope of human innovation making the chances of coming across extraterrestrial beings very slim.
• They Are Avoiding Us – Some theories go as far as asserting that aliens do exist, but for safety reasons can choose to remain inline with covert operations to avoid cultural contamination.
• We Are Not Advanced Enough – It is not out of the question that more advanced civilizations communicate in ways humanity doesn’t comprehensively grasp as yet.
• The Great Filter Hypothesis – Advancement toward achieving an interstellar civilization is difficult due to a self-destructive motivation, climate catastrophe, or any other critical challenge.

SETI (Search for Extraterrestrial Intelligence).

After millions of dollars were invested into the SETI project, it was able to develop powerful radio telescopes that were capable of picking signals from advanced civilizations. Sadly, no confirmed signals have been received. They have been searching for years but to no avail.

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