It may be an old theory that was first proposed almost 45 years ago. But with SpaceX's recent rocket launch sending many Los Angeles residents into a frenzy due to what they thought was a UFO sighting, and reports claiming that the U.S. government was secretly involved for years in the study of such phenomena, the so-called "Zoo Theory" is again making headlines for its unusual explanation as to why there has yet to be a confirmed UFO or alien sighting to this day.
The Zoo Theory was first proposed in 1973, when Massachusetts Institute of Technology radio astronomer John A. Ball wrote that aliens behave in a similar way to zookeepers, avoiding actual contact with humans to allow them to function normally and perform their everyday tasks. As Newsweek explained, the theory suggests that aliens are quietly watching us behind the scenes, but not interfering with the evolution of humanity because we are "too unevolved and uncivilized" to pose a significant threat or distraction to extraterrestrial beings.
In a 2016 article, Science Alert opined that the Zoo Theory is plausible, as there is a chance that life on other planets, if it does exist, evolved at a much faster pace than life evolved on Earth. That could lead to some interesting hypotheses about how these highly-evolved, possibly older civilizations could be much more technologically advanced than humanity currently is.
"An OC [other civilization] that is, say, a century younger than we are might not be able to communicate over interstellar distances; a century ago we couldn't," Ball wrote.
"And an OC a millennium older than we are would probably be using a technology for interstellar communications, such as modulated gamma rays, that we humans haven't yet learned how to do."As further noted by Newsweek, the Zoo Theory is just one of many that explain why we have yet to confirm alien life on other planets, though other theories are leaning toward the possibility of non-intelligent life, as opposed to extraterrestrial beings that boast of advanced technology. Scientists have been exploring worlds such as Saturn's moon Enceladus, in hopes of confirming whether the necessary ingredients of life are present. But while there could be a chance Enceladus, which is notable for its subsurface ocean, is habitable, experts believe that the moon might only be able to support microbial forms of life.
Despite the best efforts of scientists to confirm the existence of extraterrestrial life, recent efforts have not come anywhere close to proving that we aren't the only form of intelligent life in the universe. Last month, a team of scientists conducted the first extensive search for radio signals from alien life, only to come up empty due to a lack of signals from distances of 50 parsecs (963 trillion miles) from Earth in all directions. According to Cosmos, the researchers concluded that the chances of signals from high-duty-cycle radio transmitters ever being detected within that 50-parsec distance are less than 0.1 percent.
Even with the Zoo Theory in place, as well as the continued lack of evidence to support the belief that other planets can support alien life, whether intelligent or non-intelligent, some researchers are still confident in the possibility of confirming extraterrestrial life in the foreseeable future. Earlier this year, Search for Extraterrestrial Intelligence (SETI) Institute senior astronomer Seth Shostak spoke to Futurism, quipping that he "bet everybody a cup of coffee" that scientists will be able to confirm intelligent alien life within the next 20 years.