Even though there were many news about extra-terrestrial life and UFOs this year, somehow these incidents failed to give any satisfactory answer about their existence. However, an MIT radio astronomer seems to have an answer. John A. Ball had come up with the "Zoo Theory", which might reveal why aliens have not made any contact with humans till now.

Before reaching to the main subject matter, it is important to let people know that in 1967, a group of astronomers from Cambridge had detected a strange artificial radio signal from the distant Vulpecula constellation.

"We had to face the possibility that the signals were, indeed, generated on a planet circling some distant star, and that they were artificial," said Anthony Hewish, who led the team for the discovery and later won a Nobel Prize, as told by MTI Technology Review.

Although the incident was one of the biggest discoveries by the scientists and understanding of the signals published in a paper The SETI Episode in the 1967 Discovery of Pulsars, the researchers are still trying to understand the reason behind the communication gap between humans aliens through the "Zoo Theory" , which was coined in 1973.

According to Science Alert, Ball claimed that there is a possibility of alien life existing in the universe, but they are avoiding to make contact because they don't want to interfere in our daily activity and want to monitor us like a zookeeper of a cosmic 'zoo'.

In the paper, Ball wrote, "ETI (extraterrestrial intelligence) may be discreetly and inconspicuously watching us but not dabbling."

Like the Zoo theory, there are several speculations on why aliens are avoiding humankind. Some of them even suggest that if there are alien lives out there, maybe they are not advanced enough to reach out to the neighbour planets.

On the other hand, the Pentagon conducted a secret Advanced Aviation Threat Identification Program for five years, as the US Government initiated this mission to find the real truth behind UFO sightings in the nation. According to Luis Elizondo, a former Pentagon worker who ran the program, the ET is real and the government also know that.

Thus the question arises: Why the authorities are keeping it as a secret? Also, have aliens already contacted us and the entire thing is suppressed by the US government.