Study Explains Why Aliens Haven’t Reached Out to Earth... Yet

The author of the theory in question proposes that aliens may be more inclined to look for technosignatures rather than biosignatures while searching for intelligent life.

Despite mankind sending probes and radio signals into space for decades, it is yet to find any meaningful evidence of life existing somewhere beyond Earth, let alone stumble upon some advanced alien civilization.

While quite a few studies have since attempted to provide an answer to the so-called Fermi paradox – which essentially points at a discrepancy between the apparent likelihood of advanced life existing somewhere in space and the lack of evidence of its existence – new research offers a fresh take on this problem.

The author, astrophysicist Amri Wandel from The Hebrew University of Jerusalem, based his hypothesis on the premise that planets capable of sustaining life are fairly common in the universe.

In that case, Wander argued, a hypothetical alien civilization might opt to refrain from sending probes to planets with biosignatures - as such worlds may harbor life but not necessarily intelligent life – and opt to look for planets with technosignatures instead.

“The contact probability is defined as the chance to find a nearby civilization located close enough so that it could have detected the earliest radio emissions (the radiosphere) and sent a probe that would reach the Solar System at present,” the researcher explained. “It is found that the current contact probability for Earth is very low unless civilizations are extremely abundant.”

Defining the Contact Era as “the time (since the onset of radio transmissions) at which the contact probability becomes of order unity”, Wandel proposed that contact with alien civilizations via the arrival of their probes or through messages becomes “more likely”.

Finally, he noted that this Contact Era is likely “the order of a few hundred to a few thousand years," assuming that the number of alien civilizations out there is not particularly high.