Astronomers have typically used something known as the Drake Equation to calculate how many technically advanced alien civilisations there are in the Universe. In 1961, scientist Frank Drake came up with an equation outlining the variables and chances of advanced life in the universe.
It took into consideration factors such as the rate of formation of stars suitable for the development of life in surrounding planets and the number of planets per solar system.
However, as technology improves and understanding of the Universe grows, NASA and institutions such as the California Institute of Technology (Caltech) and Santiago High School, California, have updated how the chances are calculated.
The team has not provided a clear answer into what the chances are, but essentially added several factors to the Drake Equation.
One such factor which was not considered in 1961 is that species tend to find a way of killing themselves off.
For example, rats introduced to an island will consume all of the available food and then starve to death when there is nothing left.
Humans are not much better, pumping greenhouse gasses into the atmosphere knowing full well that they are contributing to the destruction of the planet.
The team suggests that when most civilisations arise, they will eventually go extinct, according to the research published in the online journal arXiv.
Another factor is the rate of abiogenesis throughout the cosmos.
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“We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life.”
The fact there has been no evidence of aliens is paradoxical, according to astronomers, and can be attributed to the Fermi Paradox.
In 1950, physicist Enrico Fermi – the creator of the world’s first nuclear reactor – came up with a paradox which says due to the age and size of the universe there is bound to be a civilisation much more advanced than ours, which begs the question: “Why is it just us?”
The solution, many scientists argue, is once a civilisation reaches a certain size, it eventually kills itself off, either through war with advanced weapons or natural disaster.