Although humans have already traveled to space, no one has yet unraveled the enigmas of the cosmological horizon or the edge of the visible Universe. As the name says, the observable Universe is what we are able to see from Earth using the scientific instruments already developed.
As the tools have advanced over centuries, astronomers were able to discover that staring into space is a way to travel to the past. When you look at a star, which is, let’s say ten years away, you are seeing an image of it ten years ago, when the starlight coming into contact with your eyes left it. The farther a cosmic object is in space, the more distant in time it is as well.
Even so, the observable Universe that surrounds us is infinitesimal in comparison to the dimensions of the wider Universe, which, most definitely, is infinite.
Alien Life Could Exist Beyond the Observable Universe
There are restrictions on how far humans can ‘travel’ back in time because of the gaze of the cosmic microwave background (CMB), the oldest light in the Universe, which allegedly beamed by the time the Universe was around 400,000 years old.
There are also limits as to how far we can glance into space because of the cosmological horizon, an edge that severs the observable Universe from the unknown range beyond it. That said, astronomers are wondering what the unobservable Universe might hold, namely, new worlds, alien life forms, or new physics.
Basically, no one knows what is beyond the horizon. However, in theory, there is no reason to believe that the Universe past the horizon is dramatically different from what we already saw to be in it.
“From everything that you can do observationally, it’s exactly the same beyond the horizon as it is below the horizon,” explained Malcolm Fairbairn, a cosmologist at King’s College London “People have tried to look to see, for example, if things are gradually changing as we get closer to the horizon and as far as they can tell, there’s no evidence for that whatsoever.”
For years, researchers have tried to fair the theoretical hypothesis that alien life exists, although they did not, allegedly, had any observational evidence for this concept, which is known as the Fermi paradox.
A Theoretical Solution to the Fermi Paradox
Tomonori Totani, an astrophysicist at the University of Tokyo, suggested that the paradox could be fixed by enlarging the range of potential ‘abiogenesis’ events, which is the scientific term for the origins of life.
Rather than putting the emphasis on the occurrence of life within the observable Universe, he suggests the possibility of abiogenesis in ‘the whole inflationary Universe,’ including everything outside the cosmological horizon, as per a paper published in February in Scientific Reports.
“The origin of life is certainly the biggest question in science, and I wanted to think about it from a viewpoint of an astrophysicist,” Totani said. “It was rather natural for me to think about the abiogenesis probability beyond the observable Universe because all astrophysicists studying cosmology know that the real universe’s size is much bigger than the observable universe.”
Totani is not the only scientist to consider the idea that life could be rich in the unobservable Universe. For example, he mentions a 2007 study by Eugene Koonin, a senior investigator at the National Center for Biotechnology Information, that implies that an infinite Universe, which could have a multiverse of numerous Universes, would make the appearance of life inevitable.
“In contrast to the traditional cosmological models of a single, finite universe, this worldview provides for the origin of an infinite number of complex systems by chance, even as the probability of complexity emerging in any given region of the multiverse is extremely low,” Koonin said in the study. “This change in perspective has profound implications for the history of any phenomenon, and life on Earth cannot be an exception.”
