The Probability of Other Complex Life in Our Galaxy
Do UFOs Exist?
In order to determine the possibility that UFOs exist we must first explore the probability that a complex, alien life form like our own exists elsewhere in our galaxy. There are approximately 50 billion planets and several billion stars in our galaxy.
How then did complex multicelluar life-forms get started here on Earth? There are primarily two opposing, but similar views; panspermia and abiogenesis. Where they differ is on their view of how life first appeared on this planet before it evolved.
Panspermia is based on the premise that only life begets life. In order for that to have happened on Earth it must have been deposited here encased in meteors, asteroids, or comet debris. It also concludes that life was present somewhere in the cosmos and that many planets, including Earth, were seeded with this life. Panspermia doesn’t specifically state where life originated, but it suggests it may have been created in some nebula cloud in the cosmos; eventually finding its way here.
Abiogenesis is based on the premise that life on Earth came from non-life. Through a series of fortuitous accidents different chemicals combined together creating what is commonly known as the “primordial ooze.” From this ooze a single living organism was born. Proponents of each view point believe that evolution took root from there.
“The Rare Earth Hypothesis”
According to Peter Ward, a geologist and paleontologist, and Donald E. Brownlee, an astronomer and astrobiologist, the Rare Earth hypothesis argues that the emergence of complex multicellular life (metazoa) on Earth required an improbable combination of astrophysical and geological events and circumstances. In order for that to happen again favorable conditions must exist in some region of the galaxy.
Ward and Brownlee refer to this region as “The galactic habitable zone,” or GHZ. In an area lacking metals, such as the outer rim or spiral arms, or an area near the galactic center with high radiation, a planet would not be able to sustain life. The GHZ of a galaxy would be the area between the two.
As stars drift away from the galactic center several significant changes occur. The metallicity of stars declines, X-ray and gamma ray radiation become less intense; therefore less harmful to complex life. Also their gravitational influence on planets decreases, thus making it less likely that a large projectile, such as an asteroid, will hit it.
Provided a star system with planets enjoys a favorable location in the GHZ, the star system must also have a circular orbit around the galactic center. If the orbit is elliptical, or oval it will pass to close to the spiral arms and galactic center where harmful radiation exists.
If a star system falls into the GHZ the planets within that system must maintain an orbit in the stars habital zone. This zone is called the “circumstellar habitable zone,” and is where a planet can maintain water on its surface. Watery planets are good candidates for supporting carbon-based life forms. Carbon compounds dissolved in water are the basis of all life on Earth.
The basic laws of physics remain constant throughout the universe. If extraterrestrial
life-forms from another planet exist then their biological profile and the materials they use and consume will be much the same as those found on Earth. These extraterrestrial
life-forms will not be mystical, or ghost like in appearance. They will not float across gaping ravines, nor will they consist of some unknown elements or compounds. They will not be “Transformers,” constructed of metal skeletons, integrated circuits and have petroleum based fluids for blood. No, they will be carbon-based, biological organisms. They may have some different attributes, but they will consume organic materials, breathe some form of air and excrete waste.
Given the set of circumstances and variables that must be present in order for life to propagate, the odds are against complex, multicelluar life having evolved on other planets in this galaxy. It would be like you winning a million-dollar jackpot and then, in the same year, winning another million-dollar jackpot. It’s not impossible, but the odds would be astronomical.
Now in the event a UFO should land somewhere on the planet unannounced, you may find yourself consuming large quantities of fermented organic material, gasping for air and excreting waste into your draws. It will get ugly!
Earth is 25,000 light years from the galactic center. The GHZ is 6,000 light years in width. There are billions of star systems out there, but only a small percentage of them has the necessary components required for supporting complex, multicelluar life. The chances that we would ever encounter intelligent, alien life, given the vast distances separating us, are almost non-existent. Neither of us would know the other exists.
In conclusion: When I add up the conditions, circumstances and complex variables that need to come into play, in order for an intelligent, technologically advanced, alien civilization to have made its way here in a spaceship, I realized I stood a better chance of winning a million-dollar jackpot. So, I checked my pockets for some extra cash, found some, and headed for the nearest casino to see if I could win one of those million-dollar jackpots. Who knows, I just might spot a UFO along the way.