When engaging in an introductory level study of astrobiology, it’s difficult to avoid a serious consideration of the question, “are we alone in the universe?”
The grassroots of those who study UFO’s have long asserted that the earth has been visited by extraterrestrial aliens. Such assertions are echoed by xenobiologists like Robert Freistas in his book “Xenopsychology” and Kurt VonDaniken in his book “Ancient Astronauts”.
They, and others, hypothesize ancient astronauts are the source of gods and mega-minds of ancient history.
Conspiracy buffs like to add that alien visitations are kept secret by NASA and other government agencies who know better. There’s alleged abductions and encounters, and sightings of unconventional aerial and aquatic vehicles which are claimed as evidence that aliens are among us.
According to Alex Kingsbury of U.S. News and World Report, there are even NASA astronauts who offer their own unexplained experiences.
But is there any credibility to these assertions? Is there empirical evidence to support the hypothesis that we have been visited by advanced civilizations from an extra solar planet? Or is the whole idea of extraterrestrial aliens complete scientific nonsense?
The Starting Point
As opposed to the more historical “Rare Hypothesis”, more optimistic theories by astrobiologists about life in the universe offer more intriguing considerations. They begin with a hypothesis, based on the Drake Equation, that life and advanced civilizations exist in the galaxy.
The Drake Equation uses a series of hypothetical factors as variables in an equation which generates the probability of life and intelligent civilizations. These hypothetical variables are not facts, they are guestimates used to test the reasonableness of the Drake Equation using conditions necessary for the processes of life.
If we are looking for planets with proper conditions to foster life, the highest probability of life appears to be in region within galaxies in which well-spaced, main sequence stars reside.
Areas close to the center of the galaxy reside in a star crowded zone, filled with high frequency radiations which are unfriendly to life. Areas too far from the center lack the heavier elements for the formation of complex organic molecules.
Stars in the middle of these regions are spared the intense high frequency radiation, but possess non-hydrogen elements for the formation of the essentials molecules of life. This raises their probability for harboring life. This region is known as the galactic habitable zone.
The Follow-Up Reasoning
If there is life in the universe, even the simplest of life, then there is evolution. If there is evolution of life, then it’s reasonable to postulate intelligent life. Given the natural evolution of intelligent life, the emergence of star faring civilizations makes for a reasonable hypothesis.
Stars in our region of space are millions, even billions of years older than our own sun. If evolution moves on a time-line anything close to that of evolution on earth, then it is likely that intelligent life emerged about 4.5 billion years after the birth of these stars.
Because of the relative age of the stars in the galaxy’s habitable zone, it’s probable that life on a typical star of the galactic habitable zone had a 1.8 billion year head start.
If that’s true, then intelligent life could have developed into an advanced, space faring civilization with ancient astronauts, long before humans even walked on two legs.
Does this list of hypotheticals, “if-and-then statements”, and reasonable guestimates count as empirical evidence? Most scientists and academics would say that such chains of unsupported logic are simply speculation. Others consider it the stuff of science fiction, pseudo-histories and imagination.
Whether one engages in the speculation, or stays with the empirical facts when considering all these ideas, the greatest intrigue is that truth is greater than fiction, and that the truth is out there. It is the unraveling of truth’s mysteries which push us on into the unknown.
By Russell Vallimont