With all that in mind, let me proceed to discuss the matter at hand.
Are we alone in the universe? In all likelihood probably not. Chances are good the observable universe is teeming with life of one kind or another..Combining the billions of galaxies we can observe, there must be total of a trillion, if not more, star systems. Most of these stars, as we are beginning to learn, have planets orbiting around them. Many of those planets lie within the "habital" zone from their sun. The "sweet spot", if you will, of a planetary system. Yes the odds are in favor of life pretty much everywhere that can support it, though not necessarily as we know it. It probably also survives in places we did not previously know it could. Two prime examples are right here in our planetary neighborhood, so to speak. Europa and Enceladus, both moons, the former of Jupiter, the latter of Saturn. Both appear to have oceans of liquid water. On both the water is buried under miles of ice. Enceladus, in particular, appears to be an oceanic planet. Water completely encompasses the little moon although it lies beneath a shroud of ice 15 odd miles thick . Given the right circumstance life similar to the creatures found in extreme depths our own oceans might survive and thrive. Their ecosystem might be centered around active heat vents on the ocean floor.
The problem with the question "Are we alone" is that it pre-supooses intelligent life. Living on an unihabited island full of trees and animals may be quite nice. You are, however, still "alone" in the human sense. We can't exactly exchange ideas and technologies with microbes in the Martian rocks or the ocean of Enceladus. They are not very talkitive and tend to be somewhat boring. The possibility of only lower life forms existing elsewhere in our solar system is probably the reason most people lose interest in our space programs. To quote Peggy Lee, "Is that all there is?" People might begin to think "Aren't there supposed to be monsters and aliens and all kinds of exotic and undiscovered peoples, places and things? This is not as advertised. We are all going home to watch Star Trek reruns". To most of us our star system is pretty empty of life. Scientists may get excited about microbial life forms but the rest of us are using some sort of cleaner to keep them off our kitchen counter tops. We are looking for the kind of stuff we read about in Isaac Asimov's books.
We are disappointed, and rightly so. We were brought up on Star Trek, and Star Wars and a hundred other space operas. Look around you. There's nobody! No starships, no intergalactic battles, not even a stupid droid! Where are all those humanoids with funny looking foreheads or ears? There should be octopus like things plotting against us on Mars. The trouble is that the universe hasn't read or watched any of these things. It does not care how H.G. Wells, Gene Roddenberry or George Lucas think things should be.
One major obstacle we lonely humans face is the sheer enormity of the space. Our galaxy alone is about 100,000 light years across. In layman's reckoning that's an astronomical number of miles, no pun intended. Every light year is roughly the equivalent of 6 trillion miles. 100,000 light years is 600,000,000,000,000,000 miles. That's 600 QUADRILLION miles. You'd need some pretty slick tech to cover a distance like that in a "human friendly" span of time. Exploring the galaxy is a complete waste If we can't live long enough to make the trip.
Yet distance isn't the greatest issue. Communication is the overwhelming hurdle, perhaps an insurmountable one. The frame of reference on which alien thoughts and languages are based may be radically different from ours. Think of the problems we have here on Earth understanding each other. All sorts of indigenous peoples see things quite differently from citizens of "developed" countries. Philology aside, time is a greater obstacle. We and our alien counterparts must be contempories. Two intelligent species must exist within a similar span of time in order to meet.. The alien race would have to be alive and kicking at the same time we are. A communication signal from another planet a thousand light years away might be just an echo of a long dead society
The two races must also be at similar levels as far as technology is concerned. Some sort of long distance communication, such as radio, must exist before one will even know the other exists. It also matters how long that communications technology lasts. Our current broadcasting technology, for instance, has been available in one form or another for about 100 years. This means our earliest long wave communication has traveled 100 light years from Earth in every direction. There is, if you will, a kind of sphere of communication around our world. Anybody intelligent enough to hear us would have to be within that sphere. The distance also effects the information anyone listening will receive. If there were Martians, they would be watching our news within hours of us seeing the evening news. On a planet orbiting Alpha Proxima, which is four light years from here. any intelligent listener would be seeing programming we saw four years ago. So it goes. A hundred light years from here they might be listening to wireless telegraphy in the form of morse code..Beyond 100 light years or so it's highly unlikely anyone would have a clue we existed.
Technological changes on either planet could also have an effect. For the last few decades we have become dependent on forms of communication that are not broadcast hither and yon. The noise of our smart phones, the Internet, cable TV and such are all virtually invisible to an observer from another planet. The equipment that once broadcast a raucus noise is being replaced by a quieter infrastructure of micro waves and other technology. Unlike radio and television, these newer technologies tend to be relatively localized. We are falling virtually silent as fewer of our signals travel outward to the stars. Unless they had gone through a similar revolution in communications any listeners who had observed our previous communication might deduce we were gone, or had just lost interest in talking.
But what of "them". In Star Trek, our world is crippled by a nuclear holocaust and our present society has come to an end. The citizens of the galaxy have no idea we exist. It's not until Ephraim Cochran turns on his warp drive that we catch their attention. In the Star Trek universe the disturbance caused by a warp field can be detected by other "warp capable" societies. The Vulcans, who are centuries ahead of us technologically, zoom down from the heavens and come to our rescue. Somehow, we humans manage to manipulate that happenstance into a Federation of races which is apparently centered on Earth. Oddly enough, most of the key members of this new society will be male, caucasion, Homo Sapiens. There will, however, still be a sprinkling of minorities thrown in for appearance sake. Many people believe something akin to this may happen, or is already unfolding. They are convinced that there is intelligent life "out there", or that some of them are already here. For varying reasons they have visited our planet, even populated it to some degree. They claim we are being visited by several alien species, that they have disguised themselves as humans and that they have even created "hybrid" alien/humans. Some think they are here to help us while others worry they are here to destroy us. It seems that some of them have yet to master the control of their strange craft and tend to crash these vessels in the most unlikely places. Strangely, most of the these incidents occur over the deserts of New Mexico. They must have overcome that issue somehow. Most of the crashes haven't occurred there for decades.
The trouble is that the alien race would be hamstrung by the same things we are. Distance, time, technology and other factors would work against them. While it is possible, I find it highly improbable that another race is presently living close enough to notice us. It is likely they do not possess the technology to reach out.and visit our little globe. As Douglas Adams wrote in Hitch Hikers Guide to the Galaxy, "Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." Just in our Milky Way it's estimated there are anywhere from 100 billion to 400 billion stars. That may mean there are at least the same number of planets. So many in fact that finding and visiting our Earth would be like pricking your finger on that proverbial needle in the haystack.
If there is an intelligent race near enough to us to matter, what if they are looking the other way? Earth lies at the outermost reaches of the galaxy. Slim pickin's if your searching for intelligent life. Their attention may be focused toward the center of the Milky Way. The star systems towards the center are closer together, making it easier to visit any number of them in a relatively short period. There would be no need to look our way. Even if they turn their attention toward us there is little to draw their immediate reaction. Interstellar distances would make it impossible to see any of our activities. Outside of our sun going supernova, there would be little to interest them. Interplanetary distances are just as isolating. While you may be able to detect our city lights from orbit, or even the moon. an observer on Mars would never see the launch of our booster rockets, the Pyramids of Egypt, the Great Wall, or perhaps even the explosions at Hiroshima and Nagasaki. From a few light minutes away we are as invisible as the micro-organisms in a drop of pond water.
In all the previous paragraphs I have discussed interplanetary and interstellar distances. These are relatively "short" in respect to the vast bulk of the known universe. Once we arrive at intergalactic measurements we find our decimal system starts to fail us. The nearest galaxy in our local group, Andromeda, is 2.5 million light years away. I am not even going to try converting that into miles. If you'd like to, just multiply 2.5 million times 6 trillion. If you do, you will understand why I scoff at folks who claim they are in contact with aliens in Andromeda, in real time, here and now. They receive little gems of wisdom on a regular basis. They say that the inhabitants of a planet somewhere in the vastness of the Andromeda galaxy are concerned for us. They are watching over our world. That is very altruistic of them. They must be really wonderful sensitive beings. I, however, rather doubt it.
The concept that anyone in one of that galaxy's several billion star systems would even guess at our existence is absolutely ludicrous. How could they possibly even know we existed, let alone know of our current situation. Any sort of message aimed our way by anyone or anything would have started on its way when mammoths and woolly rhinos were roaming the Earth. It's as if the folks in Andromeda decided to send a message to a race that barely existed yet. The species that actually survived several Ice Ages wasn't even be able to receive the message for 2500 millennia. The Andromedeans sent their personal greetings 25000 centuries before Marconi builds an instrument that can hear them. What foresight this race must have. I'm guessing they weren't hoping for an answer. Two way conversation just wouldn't work well. The folks on the other end would have to wait another 2.5 million years for the reply. I'm pretty sure that by then all evidence of their society, as well as our own, would be dust scattered to the four winds.
In summary...Yes. I do think there is and/or was intelligent life out there. The laws of chance favor that position. I do not, however, think any of them are kept frozen in the depths of Area 51. Nor are they standing in line at the convenience store. They are out there somewhere, probably looking up at the stars and asking themselves "Is there anyone out there?"
