It would be impossible to believe that intelligent life could exist on Earth given the vastness of the universe.
John Ball, a researcher at the Massachusetts Institute of Technology, proposed a hypothesis in 1973.
He suggested that aliens might be watching us as if we were animals in a zoo.
Despite billions of stars around us, humanity has not been able to find any evidence of intelligent extraterrestrial life.
It would be almost impossible for intelligent life to exist on our planet due to its infinite size and age. So why are we still unable to contact other intelligent life?
Enrico Fermi, physicist, came up with the reason in 1950. This theory later became known as the Fermi Paradox.
Scientists believe intelligent extraterrestrial life could colonize entire galaxies. However, evidence has not been found to support the hypothesis.
It seems almost impossible that intelligent life exists on our planet, given the size and age of the universe. ESA/Hubble & NASA, A. Adamo et al.
It is possible that aliens are unable to communicate with us or too far away.
There are theories that we have missed each other over time and the theory that aliens aren't interested.
Messaging Extraterrestrial Intelligence, a San Francisco-based organization dedicated to education and research on the search for intelligent living things (METI), met in Paris to find out why we still live in isolation in space.
Some people believe that aliens are always around us and act as omnipresent observers.
One theory they came up with was that aliens might have recognized our existence and observed us.
They may have kept us away from them, however.
It was also suggested that a serious solution to the Fermi Paradox be found. This is not a new idea.
Participants said that it was possible that aliens have placed us in a "space quarantine" to prevent them from interfering with or destroying our biotope. NASA/ESA/H. Teplitz and M. Rafelski; A. Koekemoer; R. Windhorst; and Z. Levay
John Ball, a researcher at the Massachusetts Institute of Technology (MIT), proposed the theory that aliens could be "omnipresently" watching us like one might see animals in a zoo or reserve.
This "zoo hypothesis" suggests that extraterrestrial scientists may be studying our culture and environment, but don't wish to make contact. It would explain why we feel so isolated so far.
Also read: Scientists discovered two planets that are not in our solar system and could be home to extra-terrestrial life.
This notion was reintroduced at the Paris-based workshop. Participants speculated that aliens might be keeping us in a "space quarantine" to prevent us from interfering with or destroying our "habitat".
This theory assumes that intelligent life exists beyond our planet, and that it may be more advanced than us cognitively.
The theory is plausible if you consider the many sci-fi movies where humanity is overpowered by extraterrestrial life. They end up reacting with panic or aggression.