Hey, You Out There - Wake Up!
I am sorry, but I'm a sceptic. 57 alien species sounds more like a kennel of mutts than the collected works of some deity with a warped sense of humor. We all know that by sheer statistical probability that lots more than 57 alien species do exist. This, however, does not mean that any of the 57 we've catalogued exist at all. It simply means that there is a greater chance for life out there than not.
If aliens have big heads with thought-telepathing brains inside, can we not just accept that they are not visiting here? Can we acknowledge the truth that aliens exist without falling prey to the notion that they have come to Earth? It seems to me that the science of aliens is much more intriguing that the science fiction of them. Life, under the right conditions, (read EARTH), can barely be stopped. Life on Earth is. Life on other rocks in the entire universe IS too. On Earth life is like a virus - actually in lots of cases life IS a virus. If the human body carries around with it 150-200 species of microbial life just on its hands everyday, then imagine how prolific and able life is around the galaxy. Of course with millions of galaxies holding sway over millions of solar systems with more planets than we can count, life -once sparked - seems to have its own way of ensuring that it keeps growing, mutating, and reproducing.
So, life can't help to have lots more than 57 catalogued alien species. Somewhere out there there must be an inventory of 57 to the ten-thousandth of live things. Imagine, if you will, the blinking eyes, all 6 of them, of some sand dwelling little urchin on the other side of "alpha faraway" poking its cylinder-like head out of the sand for the first time. Now wait 12 billion years, and you're going to have a billion other little or big things with eyes, without eyes, with brains and without, builders, collectors, species with intelligence, maybe wit, maybe even community. (Procreation works best when we can find another one like us - but not JUST like us.) Imagine that. Now multiply it by another billion or so, and wham, you got lots more than 57 alien species. You just ain't got them in your carpeting, on your highways, interstates, in your tires, or spattered against your windshield. You got them in your universe, which is your neighborhood to the 10 billionth squared.
So, even if the 57 catalogued alien species we think we have are conspirators, I am not worried. Besides, I not only have common sense to protect me and distance as a function of time as well as space, I have my own personal ultimate weapon.
I've seen a few flicks in my time and I know for a fact that MY cooties can kill their cooties, my atmosphere is pure poison for most of them, and even more importantly, I know the secret phrase to disarm at least some of them. Confronted by hostile aliens, I simply willl utter my sectret and willfull code. I'll say it aloud, only once, just loud enough to save the world. Memorize this, and save yourself: "Klaatu Barada Nikto". We all knows what happens next. Be safe, be very, very safe!