A recent study published by a team of international scientists analysed the Fermi Paradox and why we are seemingly alone in the universe.
The so-called Fermi Paradox addresses the imbalance between the probability of alien life in space and the lack of evidence for its existence.
And scientists now think there is a 30 percent chance we are alone in our home galaxy the Milky Way.
The study, titled “Dissolving the Fermi Paradox”, claims extraterrestrial life in space could be less advanced than on Earth or simply no longer exist.
Dr Anders Sandberg, Oxford University, told Universe Today: “One can answer the Fermi Paradox by saying intelligence is very rare, but then it needs to be tremendously rare.
“Another possibility is that intelligence doesn’t last very long, but it is enough that one civilisation survives for it to become visible.
“Attempts at explaining it by having all intelligence acting in the same way – staying quiet, avoiding contact with us, transcending – fail since they require every individual belonging to every society in every civilisation to behave in the same way, the strongest sociological claim ever.
“Claiming long-range settlement or communication are impossible requires assuming a surprisingly low technology ceiling.
“Whatever the answer is, it more or less has to be strange.”
The famous Drake Equation proposed by astronomer Frank Drake in the 1960s purports the sheer size of the cosmos should yield a great number of alien civilisations.
The mathematical equation factors in star formation rates, the number of hospitable planets and how far communicate signals need to travel through space among others things.
But Dr Sandberg and his colleagues Eric Drexler and Toby Ord broke the equation down to incorporate new elements, such as the chemical origins of life, which complicated the matter.
The scientists argued the equation is full of uncertainties and is “open to bias”.
Dr Sandberg said: “Many parameters are very uncertain given current knowledge.
“While we have learned a lot more about the astrophysical ones since Drake and Sagan in the 1960s, we are still very uncertain about the probability of life and intelligence.
“When people discuss the equation it is not uncommon to hear them say something like: ‘this parameter is uncertain, but let’s make a guess and remember that it is a guess’, finally reaching a result that they admit is based on guesses.
“But this result will be stated as single number, and that anchors us to an apparently exact estimate – when it should have a proper uncertainty range.”