From the beginning, humankind has been studying space, whether from a telescope on Earth or one in deep space. We have found planets in other solar systems “habitable zones” but still have numerous theories on whether extraterrestrial life could be possible. Many other theories go hand-in-hand while several others repel each other. 

If you go back even just 65 years ago when the Sputnik 1 satellite was launched, a significant amount of information would take years to read over and understand even though that era of exploration with the Space Race and getting humans to the moon was a huge accomplishment for the United States and the Soviet Union. The even bigger string of theories is if extraterrestrial life exists and if so where and how.

Extraterrestrial life is not limited to aliens in the form of ET and such, it could be bacteria that have the potential to evolve. Other lifeforms could also be more evolved and live in more advanced societies. One of the greatest theories for the existence of extraterrestrial life is the Great Filter or the Fermi Paradox. To summarize the main points of the Fermi Paradox, it is an event at some point in time that would have the potential to change the universe.  However, it could happen at any time in any form including the past 4.5 billion years, we would never know for sure. 

Furthermore, space is endless and the universe is ever expanding. Many scientists believe that there are multiple universes. This would explain many phenomena that happen, however, there is not enough evidence to prove there are actually multiple universes. 

As time goes on, scientists and researchers will find out more about our universe while also discovering new theories and possibly even different life forms. However, patience will be needed since space is vast and there are many parts of just one area that still hold the unknown.