Space has long fuelled public imagination, inspiring many a budding writer in their creative pursuits, intriguing audiences worldwide and giving many the opportunity to put their heads above the clouds (literally) and dream of the infinite, perpetual possibilities out there.
For centuries, humanity has speculated the existence of life on other planets, continuously searching for any speck of evidence that humanity might not be alone in the universe, but this evidence has always been just out of humanity’s grasp.
Does life exist on some far-off planet that we may one day communicate with?
Life has an infinite number of problems, but only a finite number of solutions.
Most scientists agree that life on other planets will require the same conditions as us, namely Water, Oxygen, Nitrogen, Phosphorus, Hydrogen, and the right Temperature.
These essential factors can be detected by satellites in space such as the well-known Spitzer, Hubble and Kepler Space Telescope which can also determine the number of planets around a star and the distance they are from it, to deduce the possible presence of water and temperature.
Other factors such as the atmospheric composition can be deduced from the colour and orbit of a planet. Thousands of such suitable planets have been discovered by our telescopes.
What Is the Goldilocks Zone?
The habitable zone is the area around a star in which planets would have the right temperature for liquid water, which is often an important condition for life.
This zone is also called the Goldilocks zone because just like the fable, it is not too hot, not too cold, but is the right temperature.
Each star has its own habitable zone depending on the heat produced by the star, its intensity, the star’s fuel as well as its size. For example, a star smaller than the sun would have a much closer habitable zone than one that is larger than the sun.
Many exoplanets, or planets that orbit other stars have been found in these habitable zones.
So, Where Is Life? The Fermi Paradox
The Fermi Paradox, named after physicist Enrico Fermi, is the apparent contradiction between the lack of evidence of extra-terrestrial life and the high probability of extra-terrestrial life.
The paradox is as such: if there are so many stars in the universe, and there is a high chance of Earth-like planets orbiting some stars, these planets might develop intelligent life and eventually communicate with Earth. However, this high probability event has not happened.
The Great Filter
One possible solution to the Fermi Paradox and the general consensus is the existence of a “Great Filter” that “filters off” civilisations after a certain point in their existence.
However, scientists are unsure of what this Great Filter might be. It could be that Life is generally hard to come about. If so, the Great Filter is behind Humanity. However, it could also be ahead of humanity, an example being the not-so-farfetched event of Mutually Assured Destruction due to Nuclear Warfare, or a hostile takeover by Artificial Intelligence.
Just the thought of such catastrophic events would make one quiver. Fortunately for humanity, nobody knows what this Great Filter might be, although we know it definitely exists.
Either way, it is logical reasoning to assume that humanity can’t be alone in the universe. As social beings always in the pursuit for company, we as a race will never stop searching for the dimmest glimmer of hope.