Are we alone in the Universe?
This simple question has been asked by mankind for centuries. And, as we find that the universe is a vast and complex place, mankind ponders this question even more today than ever.
SETI set out to answer this age-old question by aiming its Green Bank Radio telescope at star systems that astronomers believe harbor the best chances of detecting life.
This directed search focuses on star systems with known exoplanets. Recently, the first directed search project has been completed and the results are in.
The SETI project used the Kepler space telescope to identify which star systems contained exoplanets within the stars’ “goldilocks zones”.
This zone is the area around a star, usually not too close and not too far, that allows for the possibility of liquid water. It is widely believed by many scientists that if a planet possesses liquid water, then chances of life are greatly increased.
However, SETI is not looking for just any type of life; the organization is focused on life capable of transmitting narrow-band (< 5 Hz) drifting sinusoidal radio emissions across the cosmos, i.e. intelligent life.
To narrow the search even further, project researchers confined the search to exoplanets not only in the habitable zone of the host star, but that also have four or more other exoplanets within the system, at least one of which is classified as a super-Earth.
At least one of the planets within the habitable zone must have an orbital period over 50 days. According to researchers, targeting planets that fit the criteria should give SETI the best chances of finding intelligent life capable of producing some sort of detectable signal.
Search the Star Systems
These parameters filtered the search down to 86 stars systems. Once these optimal candidates were selected, the Green Bank radio telescope began to listen to determine if these planets had anything noteworthy to say. The search was conducted for about three months and research team found . . . nothing.
Actually the team detected more than 50 signals; however, they were able to rule every single one of them out as being extraterrestrial.
The team determined that every signal detected by the Green Bank radio telescope was a result of Earthly interference. Andrew Siemion, of the University of California, Berkeley, admitted to the MIT Technology Review that “no signals of extraterrestrial origin were found.” (1)
So, Are We Alone or Not?
In a paper describing the study, the team wrote:
“In the simplest terms this result indicates that fewer than ~1% of transiting exoplanet systems are radio loud.” (2)
This does not raise the spirits of those hoping to listen to a radio program from E.T. However, the research does not just end with this one study.
The researchers contend that the Green Bank radio telescope is not the most sensitive piece of listening equipment that could be used.
In the paper, the team claims that the Square Kilometer Array is about 100 times more sensitive than the Green Bank radio telescope, which means that other studies similar to this one, using different technology, could have different results.
All in all, the study did not find anything to give a reason to believe that intelligent life is living in the Kepler telescope’s field of view.
However, this one study cannot be used as proof that we are alone in the universe. The study of the existence of extraterrestrial life is limited not only to the vastness of the universe, but also to the technology that researchers have at their disposal or even the technology that the extraterrestrial civilizations (if they exist) have at their disposal.