When I was ten years old my parents took me and my brother on a family vacation to Virginia. With a six hour drive ahead of us, we stopped at a Kmart along the way to stock up on provisions for the trip. While my brother picked out an Etch-a-Sketch and some cassette tapes for his Walkman (this was the 1980s, after all), I headed to the book aisle and picked out the first paperback that caught my attention: Communion by Whitley Strieber. Something about those bulging black alien eyes on the cover fascinated me, and thus my lifelong fascination with UFOs and extraterrestrials began.
Decades later and hundreds of paperback and hardcover books along the way (plus an embarrassingly insane amount of hours spent listening to Art Bell and George Noory), I had the opportunity to observe my first UFO, in the form of an oddly-shaped pink superstructure sailing erratically through the daytime sky. It appeared to be about the size of a skyscraper and it's shape could not be described as round, oval or triangular; the best way I could describe it would be as if somebody randomly and haphazardly attached a bunch of Lego pieces together. The enormous pink craft hovered hundreds of feet above the highway, rotated, and then disappeared like a ghost. I was even fortunate enough to have a witness riding in my passenger seat. However, since the strange encounter startled her to the point of momentarily losing control of her bladder all over the car seat, I won't embarrass her by printing her name (although I'm sure she's probably reading this).
You'd think that after digesting millions of words about UFOs and witnessing one with my own eyes, I'd be a true "believer". And up until a few months ago, I was. But now, after a veritable lifetime of independent research, I am forced to conclude that Earth is the only planet in the universe capable of sustaining intelligent life. Yes, that's right-- once you analyze all the data, the evidence weighs heavily in favor of the unfortunate fact that we are utterly alone. And here is why I believe my opinion is true and correct.
1. The Fine Tuning of the Cosmos
Do you have any idea how mind-blowingly precise the conditions of the universe had to have been in order to sustain life? As far back as the 1950s, scientists became aware that carbon and oxygen are produced within stars in a certain, but predictable, ratio, and even the slightest change in the resonance state of carbon would nullify the development of life. Physicist Heinz Oberhummer discovered in 2000 that even a 1% change in the strong nuclear force (the force that binds neutrons and protons together) could have up to a one-thousandfold impact on the production of oxygen and carbon in stars.
Now let's talk about the range of natural forces, with gravity being the weakest and the strong nuclear force being the strongest (the strong nuclear force is ten thousand billion billion billion billion times stronger than gravity). All of Earth's forces are precisely calibrated to sustain life. Imagine a bank vault with a combination lock containing ten thousand billion billion billion billion possible numbers. In order to get inside the vault, you have to spin the dial and land on the exact number (and you've only got one shot to get it right). Even if you're off by just one click, the results would be disastrous. Animals and humans would either be crushed, torn asunder, or hurled through the universe at unfathomable speeds. In other words, when compared to the vast range of force strengths in nature, life is dependent on an incomprehensibly narrow range. Forget about finding a needle in a haystack; we're talking about finding a single grain of sand on a beach.
But gravity and carbon and oxygen production are just two "dials" that have to be precisely calibrated to sustain life. According to Stephen C. Meyer of the University of Cambridge, there are more than 30 unique physical and cosmological parameters that require ultra-precise calibration in order to produce an environment capable of sustaining life. To put this into perspective, in order to break into the bank vault of life, you now have to crack the combination to the locks on 30 different steel doors.
2. The Cosmological Constant
The cosmological constant (the value of the energy density of the vacuum of space) also has to be finely-tuned to support life. If the cosmological constant were too large and positive, it would be a repulsive force that would have prevented matter from forming after the Big Bang. Too large and negative, the cosmological constant would be an attractive force that would reverse the expansion of the universe. Do you know what that means? It means that the very universe would re-collapse. The cosmological constant would have to be just right.
And just how precise is this calibration? According to Professor Robin Collins of Messiah College in Grantham, Pennsylvania: "The fine-tuning has conservatively been estimated to be at least one part in a hundred million billion billion billion billion billion. That would be a ten followed by fifty-three zeroes. That's inconceivably precise."
Let me sketch that out for you:
After you crack the combination to the 30 locks guarding the vault, there's still one more task you have to complete before life can exist. You now have to place your bet on a single number and spin a giant roulette wheel. This wheel, by the way, contains:
And you only have one chance to get it right.
3. Why Life Probably Doesn't Exist on Other Planets
My first two points illustrate that life-- any life at all-- requires an absurdly incomprehensible level of calibration in order to exist anywhere in the universe. But what about scientists like Carl Sagan, who estimate that there may be up to one million advanced civilizations in our galaxy alone?
Well, first we have to look at the ingredients needed for life. Humans require 26 essential elements to exist. Bacteria, on the other hand, only need about 16. So even if microbial life exists on another planet, the planet in question would need to provide at least 16 different and unique elements. This alone rules out billions of planets in our universe.
And forget about silicon-based life forms. Any atmosphere containing oxygen would cause silicon to oxidize, thereby reducing it to inert dust and rocks. It would never have a chance to form large, complex molecules needed for life. So if you are a silicon-based life form, oxygen would pretty much be your enemy. Carbon would also be your enemy, as it would react with other abundant compounds (which is why life doesn't exist on the moon of Titan). And since carbon is pretty darn abundant in the universe, well, that doesn't bode well for silicon-based life.
MIT's Sara Seager believes that for life to exist on a planet with a hydrogen-based atmosphere, methyl chloride, dimethyl sulfide and nitrous oxide need to be present. But, much like Earth, these compunds would have to be present in precise amounts. So once again you're dealing with the issue of insanely improbable calibration.
4. But what about life that doesn't require oxygen?
Even Earth has organisms that can survice without oxygen, so why couldn't this be the case on other planets? Sure, there are some mico-organisms that "breathe" methane, but this wouldn't work with larger organisms because oxygen is required for metabolic regulation. And, as we all know, the production of oxygen on Earth is dependent on plant life and marine algae. And, again, the existence of plant life and marine algae depends on precise calibrations and fine-tuning.
Take plate tectonics, for example, which helps drive Earth's carbon dioxide-rock cycle which, in turn, regulates our environment, much like a thermostat. You need plate tectonics to create mountains and landscapes that help balance greenhouse gases and regulate climate and temperature. Greenhouse gases absorb infrared energy that would otherwise burn all life to a crisp. Plate tectonics "cycles" chunks of the planet's crust into the mantle, where the internal heat from the Earth's core releases carbon dioxide (which is later vented into the atmosphere by volcanoes). This elaborate process keeps our planet's surface temperature under control and makes it possible to oxygen-producing plants and algae to exist. And you can't have plate tectonics without water, since water is needed to lubricate and assist in the moving of the plates.
In fact, this is so damn important to life as we know it that paleontologist Peter Ward and astronomer Donald Brownlee, in their book Rare Earth, state: "It may be that plate tectonics is the central requirement for life on a planet". To date, scientists have only found one place where plate tectonics exist. And that place is Earth.
5. The Galactic Habitable Zone
A habitable planet is a rare thing. Some people say globular clusters may be a good place to find extraterrestrial life. Globular clusters (such as M13), which contain around a quarter of a million stars, have a low abundance of heavy elements (carbon, oxygen, carbon, iron, silicon, etc.) and an abundance of hydrogen and helium. So while these globular clustrers can have an abundance of stars, you probably won't find many solid planets. And this high concentration of stars is so great that it would make circular orbits all but impossible. The gravitational pull of the stars would make orbits elliptical, resulting in bat-shit crazy extremes in temperature that wouldn't exactly be conducive to life.
In 1974, Carl Sagan beamed a message to M13 looking for life. What a dumbass.
Now let's look at spiral galaxies (like the Milky Way). Every part of a galaxy contains varying degrees of star formation. Parts of a galaxy where active star formation is taking place are extremely dangerous (what with all the exploding supernovae and giant molecular clouds). In spiral galaxies, these danger zones are in the spiral arms. The nucleus of a galaxy is also pretty dangerous, since these places more often than not contain enormous black holes. And then you've got the gamma rays to worry about. So that kinda rules out the possibility of habitable planets located there. As luck would have it, however, Earth is safely tucked away between the Sagittarius and Perseus spiral arms, in a very, very narrow "safe zone".
Elliptical galaxies? These low-mass galaxies, which make up the vast majority of galaxies in our universe, don't have enough heavy elements to create habitable planets. The stars in elliptical galaxies have erratic orbits, and when one of these wandering stars gets too close to a black hole, well there goes the neighborhood. Plus you've got the quasars and supernovas going off, so if there did happen to be a habitable planet somewhere in that galaxy, chances are, it wouldn't be habitable for long. It would be bombarded with gamma rays and X-rays.
So that leaves only one more place to look for life: irregular galaxies.
Sadly, there are no safe havens within an irregular galaxy. Once again, exploding supernovae and gamma radiation are the culprits.
6. The Uniqueness of Our Own Solar System
Our existence also depends on the orbits of other planets in our solar system. For instance, if Jupiter's orbit were just the teensiest bit more elliptical, it would distort Earth's nearly-circular orbit. The result would be drastic climate change that would produce an ice age so severe that it would make life as we know it extinct. So even if another Earth-like planet did exist somewhere in the cosmos, in order for it to contain life, it would also need another nearly-identical Mars-like planet, Mercury-like planet, Saturn-like planet, etc.
In 1994, a geophysicist named George Wetherill discovered that, without Jupiter, we would all be dead. Jupiter acts as a giant shield, protecting us from comets that would otherwise obliterate us. Saturn and Uranus, to a lesser extent, also serve as shields. You also have Mars (as well as the moon) protecting us from asteroids from the asteroid belt. If life were to develop on another planet, it too would require similar shields.
7. The Circumstellar Habitable Zone
The CHZ (as it is called by astrobiologists) is the region around a star where liquid water exists. This, of course, is determined by the amount of light provided by a host star. The further away you get from a host star, the more carbon dioxide you need in the atmosphere to trap in the sun's radiation and keep water from freezing. Unfortunately, you wouldn't have enough oxygen to have advanced life forms. For life to exist on other planets, the planet would need to meet all of the above criteria, and also be conveniently located within the CHZ.
8. Yellow Dwarfs and Red Dwarfs
Our sun is a G2 Spectral Type yellow dwarf, which make up about 9% of all stars in the universe. Red dwarfs, on the other hand, make up about 80%. This is important to consider because red dwarfs emit most of their radiation in the red part of the spectrum. This makes photosynthesis difficult, since photosynthesis requires both red and blue light.
Additionally, red dwarfs are prone to flaring. This isn't much of a problem on Earth, because we are 93 million miles away from the sun. But, since a planet would have to be much, much closer to a red dwarf in order to be habitable, the solar flares would render it uninhabitable.
As you decrease the size of a star, you also reduce its luminosity, so that rules out life on planets close to stars that are too small, since these planets would need to be positioned much closer to the sun in order to have liquid water. The problem with this is that being too close to the sun would increase tidal forces, causing the planet to spin downwards into a tidally locked state, with one side of the planet continually facing the sun. The sunny side would be unspeakably hot; the dark side would be damningly cold. Sure, that may not rule out extraterrestrial life, but it would certainly decrease property values.
Taking all of these things into consideration, it would seem that intelligent life could only exist in one place in the entire universe, and that place is Earth.
So what about all the UFO sightings? It very well may be that these strange objects, including the one I saw with my own eyes, are not piloted by being from another planet, but perhaps by beings from another dimension or another time. Personally, I lean toward the time traveler theory. Maybe aliens, with their spindly arms and enormous black eyes, are not inhabitants from another galaxy, but are inhabitants of Earth thousands or millions of years down the road.